‘ x , ll . \.-wl. ('9‘: .A‘ I I 13cc Ck:CXACDLrL(C$ bViESI.) RETURNING MATERIflggz Place in book drop to LJBRARJES remove this checkout from -__—_ your record. FINES will be charged if book is returned after the date stamped below. I («A-w " ’” I? “z /‘ . . x . A , "6531"”,9'lc“ A NEH MEASURE OF ATTITUDE TOUARDS RISK By Beverly Fleisher A DISSERTATION Sublitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Depart-ent of Agricultural Economics 1985 Copyright by BEVERLY FLEISHER 1985 In loving memory of my father, Oscar T. Fleisher, Jr. ACKNOWLEDGEMENTS Completion of a project such as this requires intellectual, financial and emotional support. I gratefully acknowledge the support I have received in all three areas. The Michigan Agricultural Experiment Station provided the research funds required for this project since its inception. Intellectual support and guidance came from the members of my disserta- tion and guidance committees and numerous colleagues at Michigan State University and elsewhere. Dr. Lindon Robison, who served not only as my dissertation supervisor but also as my thesis supervisor and major profes- sor during my Ph.D. program, has truely been a mentor extraordinaire, encouraging me to takle new areas of research and publish the results. The members of my dissertation committee each contributed to the completion of this project in invaluable ways. Dr. Lester Manderscheid provided thought- ful insights into many of the issues I confronted. Dr. Jack Mchwen's assistance was invaluable in the design and administration of the question- naire. His immediate response to questions was most appreciated. Dr. Jack Meyer provided helpful assistance in clarifying theoretical issues. My thanks also go to Dr. James Bonnen and Dr. Harold Riley who, as members of my guidance committee, helped steer my through my doctoral program, and to Dr. Glenn Johnson who has provided intellectual challenges throughOUt my graduate career. iii Technical assistance was also provided by Steve Koenig and Patricia Crowley Brown who served as my agricultural experts and responded to numerous questions about corn varieties, grain dryers and loan financing. Bruce Koenig made many house calls to coax my microcomputer to do things that, alas, I alone could not make it do. Sally Hittler, Harry Holzer, and Hillard Caldwell responded with buck- etloads of patience and encouragement during the many times when I was convinced that all hope was lost. Extra special thanks go to my mother, Ruth Fleisher, who has responded with empathy and levity to many a late night long distance call, and who helped finance my microcomputer, without which I would still be typing the first draft of Chapter 1. iv TABLE OF CONTENTS CHAPTER I: INTRODUCTION: HHY 00 NE NEED A NEH MEASURE OF ATTITUDE TOHARDS RISK? .................................... 1 Some Basic Concepts and Definitions .................... 2 Currently Used Measures of Attitude Towards Risk ........ 4 Objectives of this Study ................................ 12 Overview of the Dissertation ............................ 13 CHAPTER 2: HHY DOES THE ARROH-PRATT COEFFICIENT OF ABSOLUTE RISK AVERSION INDICATE UNSTABLE ATTITUDES TOHARDS RISK? ........ 15 ' Hhat Does the Utility Function Actually Represent? ...... 16 A Brief Digression into the Foundations of Utility ...... 18 The Importance of Heterogeneity of Preferences .......... 26 CHAPTER 3: THE CONCEPT OF INTRINSIC RISK ATTITUDE: SEPARATING PREFERENCE FOR RISKLESS OUTCOMES AND ATTITUDE TOHARDS RISK ........... 36 How Can He Measure Pure or Intrinsic Attitude Towards Risk? ................................ 37 Intrinsic Risk Aversion ................................. 38 Comparing Value and Utility Functions ................... 48 Testing the Hypothesis of Constant Intrinsic Risk Attitude ............................... 49 The Adequacy of the Present Theory of Intrinsic Risk Attitude ............................... 51 CHAPTER 4: A NEH MEASURE OF ATTITUDE TOHARDS RISK .......... A .......... 55 Independence Conditions for Additive and Multiplicative Value and Utility Functions ............ $6 Multiattribute Value and Utility Functions .............. 58 Reversals in Preference and Sign Conditions ............. 59 Economic Interpretation of Parameters k and w ........... 61 Allowable Transformations Between Value and Utility Functions ..................................... 64 Synthesizing and Applying the Results ................... 67 Appendix 4A ............................................. 80 Appendix 48 ............................................. 82 Appendix 4C ............................................. 84 Appendix 40 ............................................. 86 CHAPTER 5: EXAMINATION OF THE THEORY IN AN EMPIRICAL CONTEXT ........ 88 Holistic vs. Decomposed Assessment of Multiattribute Functions ............................. 68 Methods for Estimating Value and Utility Functions ..... 91 The Number of Attributes Used .......................... 94 Determining and Interpreting Scaling Factors ........... 95 The Respondents ........................................ 102 The Questionnaire ...................................... 102 Problems with the Questionnaire ........................ 105 Satisfaction of Independence Conditions ................ 107 The Issue of Consistency of Responses .................. 109 Appendix SA ............................................ 115 Appendix 58 ............................................ 146 CHAPTER 6: SUMMARY, CONCLUSIONS, AND ISSUES REQUIRING FURTHER RESEARCH ......................................... 148 Summary ............................................... 149 Placing the Research in Context ....................... 153 Issues Requiring Futher Research ...................... 159 Nhat Conclusions Can Be Drawn? ........................ 164 BIBLIOGRAPHY ............................................. 167 vi Figure 1: Figure 2: Figure 3: Figure 4: Figure 5: Figure 5: Figure 7: Figure 8: Figure 9: Figure 10: Figure 11: Figure 12: Figure 13: LIST OF FIGURES A von NeumanneMorgenstern Utility Function and the Rela- tionship between Arrow-Pratt, Risk Premium and Certainty Equivalent Measures of Atttitude Towards Risk ........... 10 The von Neumann-Morgenstern Utility Function as a Homomorphic Mapping ................................ 17 Value Functions of Two Individuals with Constant Marginal Value of Money ........................ 27 Value Functions of Two Individuals without Constant Marginal Value of Money ........................ 29 Value Functions and Indifference Curves of Two Individuals who Have Constant Marginal Value of Money and Homogeneous Preferences ....................... 31 Value Functions and Indifference Curves of Two Individuals who Have Constant Marginal Value of Money and Heterogeneous Preferences .................... 32 Value Functions and Indifference Curves of One Individual in Two Situations with Constant Marginal Value of Money and Heterogeneous Preferences ............ 34 Pure Risk Atttitude as a Function Transforming Value Functions to Utility Functions on the Real Line ......... 39 Value and Utility Functions for the Case of Intrinsic Risk Neutrality ............................... 42 Value and Utility Functions for the Case of Intrinsic Risk Aversion ................................. 46 Value and Utility Functions for the Case of Intrinsic Risk Pronenss ................................. 47 Indifference Curves for Two Attributes which Meet the Independence Conditions Required for Additivity ......... 53 Relationships Among Independence Concepts ................. 60 vii Figure 14: Figure 15: Figure 16: Figure 17: Figure 18: Figure 19: Using Lotteries to Interpret k in a Multiplicative Multiattribute Utility Function ......................... 62 v(x), u(x) and u(v) for an Intrinsically Risk Prone Individual when v(x) = E ln x ........................... 6B v(x), u(x) and u(v) for an Intrinsically Risk Prone Individualwhen v(x) = I x2 .............................. 71 v(x), u(x) and u(v) for an Intrinsically Risk Averse Individualwhen v(x) = I ln x ............................ 72 v(x), u(x) and u(v) for an Intrinsically Risk Averse Individualwhen v(x) = E x2 .............................. 74 v(x), u(x) and u(v) for an Intrinsically Risk Averse Individual when v(x) = fl ln x ........................... 77 viii Table Table Table Table Table LIST OF TABLES Methods for Estimating Value or Utility Functions ........ 92 Number of Individuals Nho Had Difficulty Answering Specific Types of Questions ............................ 107 Number of Responses Satisfying Independence Conditions ... 107 Frequency of Additive and Multiplicative Value and Utility Functions by Decision Context .................. 108 Frequency of Combinations of Different Types of Value and Utility Functions by Decision Context ........ 109 ix CHAPTER 1 INTROUJCTION: WY 00 NE NEED A NEH MEASURE OF ATTITUDE TOHARDS RISK? The concept of an attitude towards risk which is unique to the in- dividual is used both formally and informally by agricultural economists concerned with a wide variety of problem settings in which uncertainty is present. Attitudes towards risk are used formally in predictive models of agricultural sector participants' responses to changes in the economic, institutional or technological environments and in formulating extension reco-endations. Perhaps more commonly, the truism that "all farmers are risk averse“ is used by agricultural economists and policy makers in less formal analysis. Young, et. al. (1979) state that I'knowledge of risk preferences of individual agricultural producers is necessary for many useful private managerial and public policy analyses of decision making under risk.“ Agricultural economists have perceived the need to incorporate the effects of uncertainty into their analysis and have, over the past thirty years, engaged in numerous endeavors to quantify attitudes towards risk. Despite this accumulated body of research, the profession still has little consis- tent evidence supporting the assuqation of risk aversion on the part of agricultural sector participants. Nevertheless, this assumption continues to be the cornerstone of much of the disciplinary and problem solving research done today. Young, et. al. expressed their primary reservations with the elicita- tion and use of risk preferences as twofold: (1) the errors inherent in previously used measurement techniques, and (2) the possible temporal instability of preferences. It should also be noted that there is little evidence to support the common assumption that risk preferences elicited in one decision context can be generalized to other contexts, even at the same point in time. This dissertation focuses on the problem of the instability of at- titudes towards risk indicated by current measures. The research is motivated by the assumption that individuals‘ attitudes towards risk are stable, and that the perceived instability is due to the measures used. He begin with an examination of why currently used measures of attitudes towards risk result in the appearance of instability. A new measure of attitude towards risk is then developed which is hypothesized to be stable globally within one decision context, and also both across decision con- texts and intertemporally. Sggg,§g§15_Conggpts and Definitions The study of attitudes towards risk and their formal use in analysis is part of a broader field of inquiry known as decision theory or decision analysis. Although used extensively by economists and agricultural economists, decision theory finds its home in no one discipline. Develop- ments in decision theory are drawn from and used in many disciplines in- cluding economics, management science, mathematical psychology, finance, anthropology, sociology, statistics and systems science. Hhile this conflux of numerous, seemingly unrelated, disciplines often creates definitional problems (Robison and Fleisher, 1983), it, at the same time, provides a varied and fertile set of conceptual frameworks from which to draw. In fact, the foundations for much of the development of the new measure of attitude towards risk presented in this dissertation come not only from economics, but also from recent theoretical work in other disciplines including mathematical psychology, management science and systems science. An example of the definitional problems inherent in work in the field of decision theory is the term relative risk aversion; economists encoun- tering this term immediately think of the Arrow-Pratt coefficient of rela- tive risk aversion, described later in this chapter, while mathematical psychologists think of an entirely different concept, to be discussed in detail in Chapter 3. To avoid confusion, the mathematical psychologists concept of relative risk aversion is referred to as intrinsic risk aversion in this document. Hhile many terms will be defined as they are needed, several concepts used throughout the dissertation are defined here. Risk and uncertainty, two of the most commonly used terms in decision theory, are probably the most difficult to define. In fact, Stiglitz has commented that, “Risk is like love; we have a good idea of what it is, but we can't define it precisely“ (Roumasset, 1979, p. 4). Fleisher and Robison‘s definitions will be used here. They state (Fleisher and Robison, 1985, pp. 3-4): “Certain and uncertain are adjectives used to describe events. Events with only one possible outcome are defined as certain: the single outcome has a probability of one of occurring. Uncertain events are those with more than one possible outcome: each possible outcome has a probability between zero and one of occurring. Since events are either certain or uncertain, we cannot say that one event is more or less uncertain than another. Each event is either uncer- tain or certain. A, class of uncertain events which alter the gellrbeing of either a weTT'defifiEd class of decision makers 9;, a angle—decision gaker ag @le risRy events. Riskiness, because it depends on the decision makers‘ attitudes, likes and dislikes, cannot be made more precise without first defining whose well-being is used to give meaning to the concept. Once we define the class of decision makers, we may be able to make comparative statements like action choice A's outcomes are more or less risky than 8'3. The important point to remember is that an event's riskiness depends on the preference of an individual or a class of individual decision makers. Riskiness cannot and should not be used interchangeably with the word uncertainty. Riskiness should also not be confused with the dictionary definition of the noun 'risk.‘ Risk is defined in the dictionary as the pos- sibility a: loss or injury. Lg the context gfi decision anal sis wever, a risk event ma result in favorable or unfavorable cogggguénces _gg____,d§%ision mafier. ‘— Another distinction which needs to be made is between action choices, outcomes and attributes. Action choices are defined as the set of alterna- tives available to the decision maker, including the alternative of doing nothing. In a tractor purchase decision, a set of action choices might include buying brand A, buying brand 8, or not purchasing a tractor. An outcome can be thought of as the result or consequence of an action choice. In the case of a tractor purchase, the outcome may be buying brand A trac- tor and having it live up to the purchasers' expectations. An attribute, on the other hand, is a specific characteristic of an action choice or an outcome. In the case of the tractor purchase decision, attributes of each tractor could include fuel efficiency, PTO and draw bar power. Currently Used Measures gfi Attitude Towards Risk Models of decision making and their application are as diverse as decision theory's bases. Some models of decision making are descriptive, attempting to capture and explain the cognitive processes used in making actual decisions. Others are prescriptive and are used to help decision makers make l'better" decisions. The third group can be classified as predictive. These models make no attempt to formally model decision making processes. Instead, they treat the cognitive decision process as a black box; decision makers' preferred action choices are predicted as, if they followed a certain set of procedures without assuming that these are the procedures actually used. Although increasing use is being made of prescriptive models by agricultural economists working in farm management and related fields, economists, in general, tend to be primarily concerned with predictive models of decision making under uncertainty. The research presented here also falls into this category. Hhile there are numerous models which can be used to predict preferred action choices under uncertainty, Hey (1979) estimates that the expected utility hypothesis provides the basis for over 90$ of the disciplinary work (in economics) on individual or firm behavior under uncertainty. The ex- pected utility hypothesis was first formally deduced from a set of axioms by Ramsey (1931) and later developed more fully by von Neumann and Mor- genstern (1944). The expected utility hypothesis asserts that if a decision maker's preferences satisfy certain conditions of “rationality“, their utility function elicited over risky prospects can be used to predict their preferred action choices in other risky situations. Specifically, von Neumann and Morgenstern proved that their four basic axioms imply the existence of numerical utilities for outcomes such that the individuals' expectations for lotteries over these outcomes preserve their preference orderings, i.e. greater expected utility corresponds to higher preference. In von Neumann and Morgenstern's own words, they “practically defined numerical utility as being that thing for which a calculus of expectations is legitimate' (von Neumann and Morgenstern, from Schoemaker, 1982, p. 531). Because of their role in the formalization of the expected utility hypothesis, a utility function elicited over risky prospects is usually referred to as a von Neumann-Morgenstern utility function. The four axioms of 'rational behavior” which expected utility maxi- Inzers are assumed to follow are: 1. Ordering: If an individual confronts two risky prospective action choices, A and 8 each with more than one potential outcome or with a Egobabilitz distribution of outcomes, he will prefer one of t two ris y prospects or will be indif- ferent between them. 2. Transitivit : If the individual confronts three risky prospEEES,A, B and C and prefers A to B and B to C, then he will also prefer A to C. 3. Continuity: If an individual prefers A to 8 to C, then there exists a unique probability, p, such that he will be indif- ferent between B and a lottery of the form pA + (1 - p)C. 4. Independence: If action choice A is preferred to 8 and C is some 0 r ottery, then the individual will prefer a lot- tery of pA + (1-p)C to the lottery p8 + (1-p)C. The four axioms of rational behavior provide both the mathematical foundations for expected utility theory and the behavioral conditions that an individual's preferences must meet to be an expected utility maximizer. Satisfattion of the behavioral requirements can be viewed as a precondition for expected utility maximization. If a decision maker's preferences con- form to these axioms, a utility function u(x) can be formulated which reflects the preferences of the decision maker. A utility function u(x) derived for an expected utility maximizer has the following properties: 1. If x1 is preferred to x2 then u(xl) > u(xz). 2. The utility of a risky prospect is equal to the expected utility of its possible outcomes. 3. The scale on which utility is measured is arbitrary; utility functions are unique up to a positive linear transformation. In addition to the four formal conditions of “rational behavior“ listed above, many applications of the expected utility hypothesis implicitly assume that several other conditions are met. These include: 1. That outcomes can be denominated in terms of a common unit. 2. That there is homogeneity of preferences for attributes of riskless outcomesl. 3. That individuals can accurately educe their preferences. 4. That individuals subjective probabilities are the same as stated “objective” probabilities.2 5. That utility functions elicited usin hypothetical decision contexts are applicable to actual dec sions. Different variants exist within the general expected utility framework depending on what type of probability transformations are allowed, how the outcomes are measured and how utility is measured. Hhile the axiomatization of the expected utility hypothesis was a major step in the development of decision theory, a suitable numerical measure of attitude towards risk was needed to arrive at quantifiable theories and predictions of decision makers' behavior. The application of the expected utility hypothesis to empirical problems was given impetus when Pratt (1964) and Arrow (1965) set forth a means of characterizing individuals on the basis of a numerical measure of their attitude towards risk. Pratt 1 Homogeneity of preferences implies that, at equilibrium, each in- dividual values equally, or derives the same amount of utility from, the last unit of each commodity purchased and that this value or utility is identical with the value or utility received from an amount of money identical to the goods' price. This assumption ignores the existance of consumer surplus. 2 Several variants of the expected utility hypothesis, such as the sub- jective expected utility and subject ve y weighted utility models do not assume that this condition holds. Readers are referred to Schoemaker (1982) for an interesting exposition on different schools of probability theory related to assumption number four. showed that a numerical measure of risk aversion, based on the rate of bending of an individual's von Neumann-Morgenstern utility function, is unique and invariant under positive linear transformations of the utility function. The measure he proposed, now known as the Arrow-Pratt coefficient of absolute risk aversion, is defined as: (1.1) r(x) = -u'(x)/u'(x). where x is income or wealth. The ArrowbPratt coefficient of absolute risk aversion can be taken at any arbitrary point on an individual's utility function. Two other measures of attitude towards risk can be shown to be related to the Arrow-Pratt measure. A risk premium measure of attitudes towards risk can be derived from the same individual's utility function by asking “for a small gamble with variance 02 and mean xt, what risk premium, I, would the individual be willing to pay to eliminate the uncertainty?“ Pratt showed that the ap- proximate relationship between these two measures, when the ArrowePratt coefficient is taken at the mean of the gamble, is: (1.2) s = r(x*)63/2 or that the risk premium, I, is equal to the value of the coefficient of absolute risk aversion at the mean of the gamble times the variance of the action choice divided by two. The certainty equivalent, CE, of the same gamble can be found by replacing I, the risk premium, with x* - CE. This can be expressed as: (1.3) CE = x. - r(x*)01/2 = x* - m Pratt then inferred that the more risk averse the individual, the larger the risk premium he would require. Furthermore, he asserted that, at a point, or 'in the small,” individuals could be ordered according to their attitude towards risk measured in terms of a risk premium, a certainty equivalent, or the Arrow-Pratt coefficient of absolute risk aversion. A von 'Neumann-Morgenstern utility function and the three related measures of attitude towards risk are shown in Figure 1. Note that these are all local measures of attitude towards risk. If the attitude towards risk is constant over the range of outcomes associated with one decision, Pratt showed that the utility function must take one of the forms: u(x) is a positive linear transform of x if r(x) = 0 u(x) is a positive linear transform of -e‘°x if r(x) = c > 0 u(x) is a positive linear transform of e-cx if r(x) = c < 0 Pratt also defined a local measure of relative risk aversion defined (1.4) rr(x) = -(x * u'(x))/u'(x) This coefficient measures the elasticity of the marginal utility of wealth and is invariant not only with respect to changes in units of measurement of utility but also with respect to changes in units of wealth. Numerous empirical studies have measured farmers' attitudes towards risk using one of the three related measures discussed above. The measured attitudes towards risk have often been used to order farmers according to their risk attitude, predict preferred action choices, or attempt to estab~ lish correlations between socio-economic attributes of individuals and their risk attitudes. Readers interested in a review and discussion of this literature are referred to Fleisher and Robison (1985). Although the large body of literature on measurement of attitudes towards risk in agricultural settings will not be reviewed here, several of the points made by Fleisher and Robison must be noted because of their 10 u U(X) u(8)-8.3 // u(5)=6.4 .5u(8) +.5u(2) , -5.66 g ' I E I u(2)=2.8 } l Hi i : n l .I .I L 4' 2 4.1 5 8 x x* u(x) = 4 ln x CE = 4.1 r(xs) = 1/xs I = .9 Hhen presented with and equal chance lottery between 2 and 8, or 5 for sure, the individual selects 5, since: CE = x - r(xs) 01/2 = x* - m which, in this case yields: 4.1 = 5 - .2 * 9/2 = 5 — .9 Figure 1: A von Neumann-Morgenstern Utility Function and the Relationship between Arrow-Pra t, Risk Premium and Certainty Equivalent Measures of Attitudes Towards Risk. 11 direct bearing on the present study. The first is the caveat that measures of attitudes towards risk taken at a point on the individuals' utility function are local measures and cannot justifiably be used to order in- dividuals according to their attitudes towards risk "in the large“. The second is that when utility functions are elicited using hypothetical money gambles, they have not proven very useful in predicting preferred action choices in ''real world' situations. Third, when attitudes towards risk for the same individuals are taken at two different points in time, they are not stable (Halter and Mason, 1971: Hhittaker and Winter, 1980: Love and Robison, 1984; Mosteller and Nogee, 1951). In addition, Hildreth and Knowles (1982) cite several empirical studies of individuals‘ risk preferences that produced apparently risk neutral or risk loving responses in cases where the decision makers' true preferences would be expected to be risk averse. These factors support the contention that something other than attitude towards risk influence preference rankings. In addition, several studies have examined the conformance of decision makers' preferences with the behavioral conditions specified by the axioms of expected utility theory. Of particular concern is the independence axiom which assumes invariance of preference between certainty and uncertainty when other things are equal. According to Machina (1982, 1983), empirical/experimental research on the independence axiom has uncovered four types of systematic violations of the axiom: the common ratio effect, the common consequence effect, oversensitivity to changes in small 12 probabilities and the utility evaluation effect. Only one type of the common consequence effect will be discussed here.3 Kahneman and Tversky (1979) observed a certainty effect by which deci- sion makers viewed outcomes obtained with certainty as being dispropor- tionately larger than those which are uncertain. A related experiment on the effect of certainty versus uncertainty was performed by Ellsberg (1961) showing systematic violation of the independence axiom. Other authors (e.g. Masson, 1974) have shown that violations of the independence axiom create discontinuities in the utility function at certainty. Heiss (1984) has demonstrated that the certainty effect can be modeled by allowing decision makers to have 'two-rule' type measurable utility functions reflecting dichotomous behavior towards certainty and uncertainty. He also demonstrates (Heiss, unpublished) that predicted behavior under uncertainty when one allows for dichotomous behavior differs from the predictions made when this dichotomy is not allowed. Despite' these findings, most empirical applications of the expected utility hypothesis and other models of decision making under uncertainty which derive local measures of attitude towards risk treat them as true indicators of preferences and employ them in generalized conclusions about the risk attitudes of a population or the ordering of individuals within the population. 3 For a discussion of oversensitivity to changes in small probabilities, the reader is referred to Kuenreuther and Slovic (1978). A discussion of the utility evaluation effect may be found in McCord and de Neuf- ville (1983) and a discussion of the common consequence effect can be found in Raiffa (1961) and Slovic and Tversky (1974). 13 Objectives gfi,th1§_§tggy, This goal of this undertaking is to contribute to the improvement of the application of decision theory in agricultural teaching, research and extension by developing a new measure of attitude towards risk which separates the influence of preferences for attributes of outcomes under certainty from like or dislike of Uncertainty. The first step towards attainment of this goal is to show why the Arrow-Pratt coefficient of absolute risk aversion is not stable across decision contexts and therefore why agricultural economists can not continue to use coefficients derived in one decision context to predict preferred action choices in other decision contexts or at other points in time. The second step is to develop a new measure of attitude towards risk which is hypothesized to be stable and therefore can be used to generalize across decision contexts and compare individual's attitudes towards risk. The third step is to examine the new measure more closely through empirical application. Overview 9: the Dissertation This chapter has provided a brief introduction to the problem addressed in the dissertation. Chapter 2 examines the question of why risk attitudes appear to be unstable when measured using the Arrow-Pratt coefficient of absolute risk aversion. This includes a brief digression into the founda- tions of utility theory and some of the controversies, questions, an am- biguities in terminology which have arisen and often obscured our under- standing of utility functions and what they actually represent. Chapter 3 14 introduces the concept of intrinsic risk aversion4. These chapters provide the foundation for Chapter 4, in which a new measure of attitude towards risk is developed and discussed. Chapter 5 discusses the procedures used to empirically examine the new measure and presents the limited conclusions that can be drawn from this exercise. Chapter 6 contains a summary of the research and observations regarding application of the results as well as a discussion of issues requiring further research. The seasoned reader of dissertations will note that there is no chapter which is explicitly devoted to a review of the pertinent literature. Be- cause the literature/ which provides the background for this study is so diverse, ranging from measurement theory to management science, individual sources are cited in the text where they are most applicable. 4 This concept is referred to as relative risk aversion in the mathemati- cal psychology and much of the management science literature. Since this concept of relative risk aversion bears no relationship to the Arrow-Pratt coefficient of relative risk aversion confusion will be reduced by referring to this concept by a new, if less descriptively accurate, term. CHAPTER 2 HHY DOES THE ARROH-PRATT COEFFICIENT OF ABSOLUTE RISK AVERSION INDICATE UNSTABLE ATTITUDES TOHARDS RISK? Various authors have suggested that the instability in empirically measured Arrow-Pratt coefficients of absolute risk aversion is due to a wide variety of problems including measurement error, subjectively held probability estimates which differ from those given in the elicitation procedure, discontinuities in the utility function and ”other factors". Hhile it is recognized that all of these arguments may have validity, they will not be examined closely in this chapter. Instead, we will focus on what the von Neumann-Morgenstern utility function actually represents and how this affects what the Arrow-Pratt coefficient of absolute risk aversion derived from the utility function actually characterizes. He begin by using a measurement theoretic approach to examine what the utility function actually represents. This is followed by a brief digres- sion into the development of utility theory and the expected utility hypothesis' place in this context. Special attention will be paid to two assumptions: constancy of the marginal utility of money, and homogeneity of preferences. This discussion is then used to examine what effect the viola- tion of these assumptions has on the use of Arrow-Pratt coefficients as a numerical measure of attitudes towards risk. 15 16 Haas Q9g§,thg_Utility Function Actually Represent? Measurement theory starts with an observed or empirical relational system (e.g. someones likes or dislikes for outcomes), called the domain. A mapping to a numerical relational system (e.g. a utility function), called the range, is sought. This mapping preserves all of the relations and operations ( e.g. preferences) in the original observed or empirical sys- tem. Axioms of the expected utility hypothesis can be conceived of as the representation theorem which does the mapping. Hhile many questions raised in examining the axioms as a representation theorem are of concern to those interested in decision theory, they are not the major focus of this chap- ter. Instead, our present concern is with what the representation theorem is actually mapping. The expected utility hypothesis takes as its domain preferences over probability distributions over outcomes and maps this to a utility function whose range is the real line from which attitudes towards risk are derived. This mapping is shown in Figure 2. The conceptualization of the domain and range for the utility function under uncertainty results from von Neumann and Morgenstern's use of risky prospects in developing utility functions. This utility function differs from the utility function in standard consumer theory in that the latter involves only certain outcomes. These utility functions map from the domain of preferences over riskless outcomes to a range on the real line. This standard consumer theory preference function will be referred to as a value function to distinguish it from a von Neumann-Morgenstern utility function Cover risky prospects. 17 preferences over utility function whose over outcomes A X I probability distributions --- g ---> range is the real line S [domain] [representation theorem] [range] Figure 2: The von Neumann-Morgenstern Utility Function as a Homomorphic Mapping 18 Note that the expected utility hypothesis takes as its domain preferences over probability distributions over outcoggs. If the repre- sentation theorem provides a mapping which preserves all relations and orderings in the domain (a homomorphic mapping), the resultant utility function incorporates both preferences over probability distributions and preferences over outcomes. The former may be viewed as containing informa- tion about attitudes towards risk while the latter contains information about preferences for riskless outcomes. The obvious question, then, is if the utility function whose range is the real line incorporates information about both preference for riskless outcomes and attitude towards risk, can we use the rate of bending of the utility function [the Arrow-Pratt coefficient] as a measure of attitude towards risk? Before this question can be answered, we must have a better understanding of value and utility functions and the assumptions each embodies. A Brief Digression into the Foundations g§_Utility_ This digression into the foundations of utility is being made in the hope that it will clarify some of the confusion surrounding what the utility function actually represents. At the same time it will highlight the assumptions in the expected utility hypothesis which are a direct carryover from the earlier cardinalists and which give rise to the present concern over the use of the Arrow-Pratt coefficient of absolute risk aver- sion as a measure of pure attitude towards risk. Many attacks on the ex- pected utility hypothesis are based on earlier criticisms of cardinality as used by the material welfare school [Baumol, 1951: Majumdar, 1958]. mile some of these criticisms remain valid when examining the expected utility 19 hypothesis, many others ignore the important distinctions which can be made between the early and new cardinalists. Discussion of the historical foundations and concepts of utility are made more complex by the fact that the distinctions between what we shall call the early cardinalists, the ordinalists, and the new cardinalists cannot be made purely on the basis of debate over the l'measurability" of utility. Cardinalists and ordinalists also disagree among themselves and with each other as to whether utility is an introspective or a behavioral concept, on its importance in welfare economics, and its use in determining preference orderings among risky prospects. Early cardinalists viewed the fundamental natural operation in the measurement of utility as taking place within the mind of the subject: utility measurement was a process of introspectively weighing the amounts of satisfaction associated with different outcomes. Elicitation of utility was simply a matter of mapping these internal measures of satisfaction onto the real number line. It was argued that since individuals could not only order degrees of satisfaction but also judge their strength of preference for each outcome in a cardinal fashion (e.g. outcome A provides twice as much satisfaction as outcome 8), the utility function derived from the mapping process was cardinal. In other words, not only was the mathematical representation viewed as cardinal, but the extra-mathematical interpreta- tion was also cardinal in nature. Three important assumptions about the nature of utility are implied by the early cardinalists. First, an increment of utility is not only quan- tifiable in principal, but also is measurable in terms of money. Secondly, utility is a measure of worth to the individual and does not necessarily imply any preference ordering; it is simply a measure of the amount of 20 satisfaction an individual could obtain from a given outcome. Furthermore, this satisfaction refers directly to the meeting of physical needs, not the preference for more abstract desires. Third, utility is additive and inter- personally comparable. It was argued that if we look upon money as a measure of general pur- chasing power, then there can be no objection to regarding it as an in- dicator of alternative welfare-yielding situations. Therefore, the amount of sacrifice, in terms of money, which a person would make rather than go without a particular thing is a measure of his welfare derived from it. The difficulty with this conclusion rests with a further assumption. If money provides the measuring rod of utility then, as with all measuring rods, its unit must be invariant; it must measure the same amount of utility in all circumstances. The first dollar must mean the same to the individual as the hundredth or millionth. This means that one has to assume constant marginal utility of money. The importance of this assumption will be discussed below. Jevons was one of a group of economists who shifted the focus of utility from a purely individualistic approach to that of explaining be- havior and conditions of exchange in a market economy. Hhile Jevons still believed (albeit ambiguously) in the cardinality of utility, he did not view "total utility” for any good as being intrinsically measurable or interpersonally comparable. Instead, he hypothesized that interpersonal comparisons of welfare could be obtained through the use of the concept of marginal utility. He states in his second edition of The Ihggry_g§_flg]1tir gal Eggnggy (1879, from Stigler, 1950, p. 317) that 'It is from the quantitative effects of the feelings that we must estimate their comparative amounts. I never attempt to 21 estimate the whole pleasure gained by purchasing a com- modity; the theory merely expressed that, when a man has purchased enough, he would derive equal pleasure from the possession of a small quantity more as he would from the money price of it.‘ Jevons uses this to argue that, at equilibrium, welfare is maximized be- cause each individual's marginal utility is equal, and thus, all in- dividuals would obtain the same degree of satisfaction of needs from the last unit purchased. From this argument comes the assumption of homogeneity of preferences across individuals, implying that the last unit purchased by each individual is valued by each individual at the market price of that unit. Marshall extended Jevons' concept of utility to formulate a hypothesis of diminishing marginal utility for goods. Marshall argued that an incre- ment of utility (marginal utility) is quantifiable in principle and is actually measurable in terms of money. He also asserted the law of nega- tively sloping demand curves in all generality (Marshall, 1890, pp. 159- 160, from Stigler,1950, p. 326): “There is then one law and only one law that is common to all demand schedules, viz. tha the greater the amount to be sold, the lower will be the price at which it will find purchasers.“ It is important to note that the Marshallian demand theorem cannot be derived from the hypothesis of diminishing marginal utility except in a one commodity world without contradicting the assumption of constant marginal utility of money with respect to changes in prices and income. If this difficulty is avoided by giving up the assumption of constant marginal utility of money, then money can no longer provide the measuring rod for 22 utility and we can no longer express the marginal utility of a commodity in units of money. Hith the advent of an ordinal concept of utility, utility was no longer viewed as a psychological entity measurable in its own right. Instead, utility was viewed as a convenient label for the explicit value of a func- tion which described consumer behavior. Not all ordinalists argued that utility was not quantifiable in principle. Their fundamental argument centered on the fact that a basic understanding of the behavior of par- ticipants in an exchange economy did not depend on the assumption of car- dinally measured utility. Assumptions regarding cardinality in extra- mathematical interpretation were viewed as extraneous to the issues at hand; since equally strong results for price theory could be obtained without this assumption, there was no reason to suppose that anything more than ordinal utility was required. The move to an ordinal concept of utility was not necessarily a total rejection of the mathematical concept of measurable utility; its extra-mathematical interpretation was simply unnecessary. Hith the publication of von Neumann and Morgenstern's Ihgggy,gf_§a___ agg_Economic Behaylgg in 1944, the debate over the cardinality of utility was rekindled. From a measurement theoretic perspective, von Neumann- Morgenstern utility is cardinal because the utility scale has interval properties (it is unique up to a positive linear transformation) However, from a preference perspective, von Neumann-Morgenstern utility is ordinal in that it provides no more than ordinal rankings of lotteries. It differs from earlier cardinal utility in that utility is viewed not as I'measurable" in the sense that it is correlated with any significant economic quantity such as the quantity of feeling or satisfaction or intensity. It is 23 cardinally measurable only to the extent that the numerical operation of forming mathematical expectations on the basis of these numbers would be related to observable behavior, so as to be emprically meaningful. Von Neumann and Morgenstern's utility also differed from early car- dinalists in that they use risk choices to define utility differences, not to estimate introspectively ascertained differences. Therefore, von Neumann-Morgenstern utility should not be interpreted as cardinally measur- ing strength of preference for uncertain outcomes; as a preference measure it is strictly ordinal. The distinction between this new cardinality in the purely measurement theoretic sense, and the earlier cardinalists is made more confusing by the strong similarities in notation and methods used to determine the outcome which maximizes utility. Ellsberg (1954) illustrates the source of this confusion with an example. Suppose an individual who prefers A to B, B to C and A to C must choose between having a lottery ticket offering A with probability p or C with probability 1-p. Both early cardinalists and von Neumann and Morgenstern would assign a triplet of numbers, UA, U3, and Uc, to the three outcomes with the property that UA > U3 > Uc. This triplet is a utility index for the three outcomes since their order of magnitude reflects the order of preference. Next, both would form the expression: (2.1) U3 is greater than, less than, or equal to pUA + (1-p)Uc where p and l-p are the respective probabilities of A and C. In each case the individual would choose the prospect with the highest mathematical expectation of utility. Furthermore, for both the early car— dinalists and von Neumann and Morgenstern, utility would be said to be 24 measurable. The necessity of this assumption is seen if the expression is rewritten: (2.2) p(UA-UB) - (1-p)(U3-Uc) is less than, greater than, or equal to 0 The rewritten expression shows clearly that the rules rely on comparing differences in utility. In order to retain consistency in results, it is necessary to find some operation that gives meaning to differences in utility numbers, and hence to the numerical operations implied by the rule. A utility index which is ordinal in the measurement theoretic sense (unique up to a monotone transformation) would not satisfy this requirement. There- fore, a more restricted set of indices, which summarizes the results of the additional operations as well as preferences, must be used. This require- ment is satisfied by the set of indices which are invariant up to a posi- tive linear transformation, or, in measurement theoretical terms, cardinal. The similarity between von Neumann Morgenstern and early cardinalist indices is that both require a utility index determined up to a positive linear transformation. However, the differences between utility points could be different for the two indices. Moreover, the indices would, in general, but not always, be monotonic and not linear transformations of each other; preservation of orderings requires a positive linear transfor- mation of utility but only a positive monotonic transformation of expected utility. Therefore, predictions based on the rule of maximizing expected utility could differ for the two approaches. A more fundamental difference exists between the two approaches; early cardinalists would come to their conclusions regarding an individuals choice between the options, one of which is a risky prospect, without ever observing that individual's behavior in other risk situations. For von Neumann and Morgenstern, it would be necessary to observe the individual's 25 behavior in other risk situations, involving different outcomes or the same outcomes with different probabilities. Utility is defined by an individual's choices among risky prospects. Hhere early cardinalists postu- lated a type of consistency between individual's risk choices and their feelings of relative differences in desirability of the outcomes, von Neumann and Morgenstern hypothesize simply a consistency between risk choices and other risk choices. However, von Neumann and Morgenstern's break with the early car- dinalists is not as complete as it may seem from the discussion above. They state (von Neumann and Morgenstern, 1944, p. 8): '..He shall therefore assume that the aim of all par- ticipants in the economic system, consumers as well as entrepreneurs, is money, or equivalently, a single monetary commodity. This is supposed to be unrestrictedly dividible (sic) and substitutable, freely transferrable and identical, even in the quantitative sense with whatever 'satisfaction' or 'utility' is desired by each participant.“ In addition, as Schoemaker (1982, p. 533) points out, '..(P)references among lotteries are determined by at least two separate factors: namely (1) strength of preference for the consequences under certainty, and (2) attitude towards risk. The NM utility function is a compound mixture of these two without direct resort to interval comparisons or strength of preference measures. As a preference theory, it is wholly ordinal. Nevertheless, it implicitly assumes that a neoclassical type of utility exists, otherwise it would not be possible psychologically to determine the certainty equivalence of a lottery." 26 [he Igpgrtance gfi_Heterogeneity of Preferences In describing the environment in which the expected utility hypothesis may be applied, von Neumann and Morgenstern employ a very restrictive set of initial conditions and auxiliary assumptions.l For money to serve as the measuring rod of "satisfaction'' or I'utility" each individual must have constant marginal value2 for money. For money as a measuring unit to be ”...unrestrictedly dividable and substitutable, freely transferrable and identical for whatever satisfaction..." (von Neumann and Morgenstern, 1944, p. 8) preferences and the utility function must be homogeneous. In other words, indifference curves for any two goods, or one good and money, must be straight lines with slope of -1 and each individual must value goods at their market price. . Unfortunately, empirical evidence does not lend credence to the use of these initial conditions and auxiliary assumptions. The following examples will demonstrate the importance of violation of these conditions and as- sumptions when the von Neumann-Morgenstern utility function and Arrow-Pratt coefficients of attitudes towards risk are used to predict preferred action choices in the real world. As a base for comparison, Figure 3 shows the value functions for two individuals who conform to von Neumann- Morgenstern's set of initial conditions and auxiliary assumptions. The reader will recall that the independence axiom of the expected utility 1 Giere (1979, pp.87-88) defines initial conditions as “...either the occurrence of a state of the system or a statement describing this occurrence.‘ and auxiliary assumptions as “...additional assumptions about the system being stud ed and about its immediate environmen .' 2 In the literature, this phenomenon is usually referred to as constant marginal utility for money. Since we are distinguishing between utility as preference for risky outcomes and value as preference for riskless outcomes, the term constant marginal value for money is used here. 27 v / " /’<$’ e 6 -— - P—-- - 2 z, 6 $ 2 4 6 5 (tractor v(tractor / services) 6" services) o~< \ _\___ I I I I I I I I 2 I i 2 —---- . I I I I' I I I I l I I I I I I _1 I I 4 6 2 4 6 tractor services tractor services 0 $1 per unit 0 $1 per unit $ $ tractor services tractor services 0 $1 per unit 0 $1 per unit Figure 5: Value Functions and Indifference Curves of Two Individuals Hho Have Constant Marginal Value of Money and Homogeneous Preferences 32 Individual A Individual 8 v($) V /($> 6 N I I I \\\\\\| N b b --- 6 $ 2 4 6 $ 8 'Iv(tractor v ////v(tractor services) 6 services) ‘////// 5 4 __ : I l I I I 3 F"" I i 2 I . I I . : I I I i 2 '4 6 2 4 6 . tractor services tractor services 0 $1 per unit 0 $1 per unit $ $ tractor services tractor services Q $1 per unit 8 $1 per unit Figure 6: Value Functions and Indifference Curves of Two Individuals Hho Have Constant Marginal Value of Money and Heterogeneous Preferences ‘ 33 primarily concerned with receiving tractor services and we present them with the standard choice between the gamble and the sure thing, individual A will be indifferent between the gamble and the sure thing while in- dividual B will choose the gamble since: (2.5) .5*v($2) + .5*v($6) .59v(2 units tractor services) + .S*v(6 units tractor services) .5*(3) + .s:(a) = 5.5 while the value of $4 of tractor services is 5. Therefore, the value of the lottery to the individual is greater than the value of the sure thing. Our current notions of attitude towards risk would indicate that individual 8 was risk prone relative to individual A. But again, if we examine in- dividual 8's preferences for riskless outcomes, we find that these explain apparently risk loving behavior when tractor services are the real concern of the individual. The value of the lottery to the individual is 5.5 while the value of the sure thing is only 5. The examples used to this point all concern comparisons of risk at- titudes of two individuals. Often, however, we use von Neumann-Morgenstern utility functions and coefficients of attitudes towards risk derived in one situation to predict the individuals preferred action choice in another situation. In other cases we determine attitudes towards risk in two dif- ferent situations, compare them, and, if they are different, assert that the individual has an unstable attitude towards risk. Figure 7 shows the case where we have one individual faced with two different decisions. In the first case it is receiving tractor services, in the second case it is receiving services from a car. Note that the individual has heterogeneous preferences; the transformation between car services and money is non— linear while the transformation between tractor services and money is v /v 6 __ 2 -....- :_____\\ $ 8 _ v I /v(tractor v(ear . . V serv1ces) | serv1ces) i I s --------, l 4 . I I I l I I I 3 ~-——- I -_---/ i I i I I I I l I I I I I l I - I I I I g I I 2 4 6 2 4 6 tractor services car services 0 $1 per unit @ $1 per unit $ $ tractor services car services @ $1 per unit @ $1 per unit Figure 7: Value Functions and Indifference Curves of One Individual in Two Situations with Constant Marginal Value of Money and Heterogeneous Preferences 35 linear. Hhen presenting the individual with the standard choice bwteen $4 for sure and an equal chance gamble between $2 and $6 when he is concerned with car services, we find that he prefers the gamble to the sure thing since the results of equation (2.5) hold; when presenting him with standard choice between $4 for sure and an equal chance gamble between $2 and $6 when he is concerned with tractor services we find that he is indifferent since the results of equation (2.3) hold. Does this mean that the individual‘s risk attitudes have changed? No, the "instability“ in risk attitude only reflects heterogeneity of preferences for riskless outcomes. More complex examples could be developed for combinations of the cases where the marginal value for money is not constant and individuals do not have heterogeneous preferences. However, these would serve only to make the same point as was made in the examples presented in Figures 3 through 7: for the Arrow-Pratt coefficient to measure only attitudes towards risk for outcomes having more than one attribute, the individual's preferences for riskless outcomes would have to conform to the initial conditions that (1) the marginal value of money is constant, (2) preferences for goods are homogeneous, and (3) there is a linear transformation between money and goods. In other words, we would have to be able to justify the assumption that the value functions were linear and of identical slope for each in- dividual across commodities and that they were, in addition, of identical slope for all individuals. Chapter 3 THE CONCEPT OF INTRINSIC RISK ATTITUDE: SEPARATING PREFERENCE FOR RISKLESS OUTCOMES AND ATTITUDE TOHARDS RISK Recent theoretical work by mathematical psychologists suggests, as we do, that the perceived instability of Arrow-Pratt coefficient of risk aversion is due to the fact that the von Neumann-Morgenstern utility func- tion is a confounding of attitudes towards risk and preferences under certainty. It has been hypothesized that if the two could be separated, we would find that individuals do have a stable pure or intrinsic attitude towards risk and that only preferences under certainty change across situa- tions because of non-linear transformations between the actual attributes of outcomes and money. Hhile a measure of pure attitude towards risk or a measure of strength of preference for certain outcomes cannot replace the expected utility hypothesis as a means of predicting preferred action choices under uncertainty, pure attitude towards risk, if stable, can provide a justifiable means of generalizing across situations or comparing individuals. Schoemaker (1982, pp. 534-535) cites five reasons to separate risk attitudes from strength of preference for certain outcomes, namely: 1. Emphasizing the point that there exist different types of cardinal utility, even within the categories of preferences for riskless and risky outcomes, that need only be related monotonically. 2. Providing a means for obtaining a measure of ”intrinsic risk attitude“. 36 37 3. If intrinsic risk attitude is stable, construction of u(x) can be simplified by building on v(x), strength of preference for riskless outcomes. 4. Group decision making can be simplified by aggregating individuals' v(x) function and transforming this to a von Neumann-Morgenstern utility function using a group measure of risk attitude. 5. Cardinal utility under uncertainty is useful for welfare economics. This chapter will review the work that has been done on developing a measure of pure or intrinsic attitudes towards risk by mathematical psychologists and management scientists. Several studies which have measured individuals' utility and value functions and shown them to be non- identical will also be briefly reviewed. Several items are important to note at the outset. First, although various authors have expressed the belief that instability in Arrow-Pratt coefficients is due to the confound- ing of strength of preference for riskless outcomes and attitudes towards risk, no exposition of this problem analogous to the one presented in Chapter 2 has been published. Secondly, studies which have ascertained that the utility and value functions are not identical have not attempted to develop a relationship between the utility and value function. Thirdly, of the few studies which have developed a theoretical relationship between value and utility functions, only one has actually empirically tested this relationship. Hgy,§ag,H§,Measure Pure 95 Intrinsic Attitude Igyaygg Risk? Unfortunately, pure or intrinsic attitude towards risk is not easy to measure. However, it can be obtained indirectly from knowledge of the decision makers' von Neumann-Morgenstern utility functions over risky prospects and their strength of preference or value functions over riskless 3B outcomes. From a measurement theoretic standpoint, pure or intrinsic at- titude towards risk can then be seen as the mapping from the value function over certain outcomes to the utility function for risky prospects as shown in Figure 8. This is essentially a two stage process. First a von Neumann- Morgenstern utility function is obtained using the representation theorem contained in the expected utility hypothesis. This maps preferences over probability distribution functions over prospects to a utility function whose range is the real number line. A value function for the same certain outcomes is also mapped to the real number line using one of several avail- able representation theorems. The second, and critical step, is to develop a transformation between the value function over certain outcomes to the von Neumann-Morgenstern utility function over risky prospects. This trans- formation encapsulates the individual's pure or intrinsic attitude towards risk, or the preference over probability distributions. Intrinsic Risk Aversion 1 Bell and Raiffa (1979) first introduced the concept of a pure measure of attitude towards risk by reference to lotteries whose outcomes had been specified in a particular manner. Specifically, the outcomes of the lot- teries were first transformed to eliminate what, in our terms, are the problems of non-constant marginal value for money and heterogeneity of preference. To do this, they transformed both money and the pertinent 1 To avoid confusion with the concept represented by the Arrow-Pratt coefficient of relative risk aversion, the term intrinsic risk aversion is used to represent the concept often referred to by mathematical psychologists and management scientists as relative risk aversion. ST 1 ----- A X preferences over I utility function whose probability distributions ---- O ----- > range is the real line over outcomes g A X preferences over -------- I ----- > value function whose riskless outcomes H range is the real line 5 [domains] [representation theorems] [ranges] 5T_ .2. value function whose utility function whose range is the real line > range is the real line transformation encapsulating pure attitude towards risk Figure 8: Pure Risk Attitude as a Function Transforming Value Functions to Utility Functions on the Real Line 41 attribute of the outcome to strength of preference scales. These scales were then further manipulated so that money and the attribute of concern have constant marginal values and a constant marginal rate of substitution. They hypothesized that the von Neumann-Morgenstern utility function measured over these transformed outcomes would always take the negative exponential form and that an individual's basic psychological attitude towards risk could be captured by the value of the negative exponent. Hhile Bell and Raiffa's work was an important step in the development of the concept of intrinsic risk aversion, the development of the theory must be attributed to Dyer and Sarin (1981). They propose a method by which preferences for risky alternatives can be determined relative to strength of preference for outcomes over the same range. The following is a summary of the most important aspects of their theory. It is assumed that both the measurable value function v(x) and the von Neumann-Morgenstern utility function u(x) are monotonically increasing in x and are continuous and twice differentiable. Using the ArrowePratt measure of absolute risk aversion, defined as r(x) = -u'(x)lu'(x), as a model, a local measure of the strength of preference of an individual for an asset at level x can be defined as m(x) = -v“(x)lv'(x). Just as r(x) >,=,< 0 respectively indicate 'risk aversion“, “risk neutrality“, or “risk preference", m(x) >,=,< 0 respectively indicate decreasing marginal value at x, constant marginal value at x, and increasing marginal value at x. If the individual's value function and utility function exhibit the same rate of bending at one level of the attribute, x, as shown in Figure 9, it can be argued that the riskiness of the lottery has no effect on their preferences. Notice that the ' risk premium“, which represents the curvature of the utility function, and incorporates information about both 42 u(x) I FTT— v(x) Pn——--—-—— x1 x x* n I‘D >4 N A = risk premium = x* - Xce B = satiation sacrifice = xa - xev C = risk premium due to only attitude towards risk = Xev'xce = 0 Figure 9: Value and Utility Functions for the Case of Intrinsic Risk Neutrality. 43 attitude towards risk and preferences for the outcomes under certainty, is identical to the satiation sacrifice, which represents the curvature of the value function sacrifice and incorporates information about preferences for the outcomes under certainty. Since the utility function incorporates information about preferences for outcomes under certainty and attitude towards risk, the curvature of the utility function which can be inter- preted as the ”risk premium“ is actually attributable to the individual's preferences for outcomes under certainty, not an aversion or proneness to risk taking. At any point x, m(x) = r(x) and the individual can be said to be intrinsically risk neutral. Note that at this point, x, both m(x) and r(x) could be >,=,< 0. The important point in the measurement of intrinsic risk aversion is that they are equal. Hhen v(x) is not equal to u(x), the relationship between m(x) and r(x) can be used to define a local measure of intrinsic risk aversion. An individual is said to be intrinsically risk averse if m(x)0 from the assumptions of monotonic increases in v(x) and continuity. Therefore, we are primarily concerned with the relationship between r(x) and m(x) in the signing of b(x). 2 It should be noted that the notation used in the literature to refer to the rate of bending of the function u(v) is rv(v) rather than b(x). It has been changed here to avoid confusion with the notation used for the Arrow-Pratt coefficient of absolute risk aversion, r(x). 45 If m(x)=r(x), indicating that both the value and utility functions bend at the same rate, r(x)-m(x)=0 and b(x)=0. This indicates that the rate of bending of the utility function over risky prospects is due solely to the non-linearity of the value function for the outcomes in riskless situa- tions. Similarly, if m(x)0. This implies that the rate of bending of the utility function is due, in part, to the non-linearity of the value function and, in part, to some other factor which is assumed to be attitude towards risk. Notice that we do not treat r(x) as attitude towards risk: instead, attitude towards risk is only that part of r(x) not attributable to m(x). This is illustrated in Figure 10. The case of intrinsic risk proneness, when r(x) 0 Figure 10: Value and Utility Functions for the Case of Intrinsic Risk Aversion 47 u(x) v(x) x x xce x* x2 X A = risk premium = x* - Xce B = satiation sacrifice = x* - xev C = risk premium due to only attitude towards risk = Xev’xce < 0 Figure 11: Value and Utility Functions for the Case of Intrinsic Risk Pronenss. 4B u(x) is a linear transform of -e‘bV(X) iff b(x) = b > 0 u(x) is a linear transform of v(x) iff b(x) = 0 u(x) is a linear transform of ebVIX) iff b(x) = b < 0. These can be viewed as the function that transforms the value function into the utility function. These three functional forms are nearly identi- cal to the forms of the utility function u(x) which Pratt proves are re- quired in the cases of constant absolute risk aversion, constant absolute risk neutrality and constant absolute risk proneness. However, these trans- formations are from v(x) to u(x) rather than from x to u(x). Qggpayigg_yalge,agg_Utility Functions Numerous studies can be found in the marketing and management litera- ture in which both utility and value functions are assessed over the same attribute and then compared. These studies have been concerned primarily with measurement techniques and have tested for differences between utility and value functions rather than trying to establish a relationship between the two. A very small sample of these studies is reviewed here to give a flavor of their results. Tversky (1967) assessed value and utility functions for eleven subjects and reported that risky and riskless preference functions are not linearly related, even for fairly trivial outcomes. Fischer (1977) used ten subjects to test assessment procedures for value and utility functions. In the context of a job selection problem, he found that for five out of the ten subjects, the hypothesis that u(x) is a linear transformation of v(x) was not supported. Although Fischer hypothesizes that there exists some monotonic transformation between value and utility functions where they are not the same, he does not develop this concept further. 49 Allais (1979) reports utility and value functions for four subjects who took part in a large experiment on the assessment of subjective preferences conducted in 1952. u(x) was not equal to v(x) for any of the subjects. Currim and Sarin (1984) tested assessment procedures for riskless value and risky utility functions within the context of a job selection problem. They found that u(x) was not equal to v(x) for 30 of the 43 subjects involved in the study. Ig§51n3,§he_Hypgthesis 9f Constant Intrinsic Risk Attitude Krzysztofowicz (1983) presents the results of the only study which assesses u and v, tests the hypothesis of constant intrinsic risk attitude for all x e X, and compares the intrinsic risk attitudes of decision makers for two decisions. The experiment he conducted supplies two utility func- tions and one value function for the same subject, attribute and decision context, but for two different decisions. Krzysztofowicz elicited responses fromrsix water resource experts regarding announcement of the level of controlled releases from a multipurpose water reservoir given an uncertain supply of water. The individuals were presented with three scenarios. In the first scenario, the actual water supply was equal to the planned supply. Thus, no uncertainty was present. A value function was obtained to quantify the relative value of water through the strength of preference of the decision makers. The second scenario was termed the pessimistic deci- sion environment and the decision makers were instructed to determine the utility of increments of water received during the season if, at the begin- ning of the season, the predicted water supply was at a very low level and thus, the announced planned release was low. The third scenario was termed the optimistic decision environment and the decision makers were instructed 50 to determine the utility of increments of water received during the season if, at the beginning of the season, the predicted water supply was at a very high level and the announced planned release was high. The hypothesis of constant intrinsic risk attitude was supported for both the “pessimistic“ and “optimistic“ decision scenarios. However, only three of the six subjects had the same intrinsic risk attitude for both decisions. The remaining three subjects changed their intrinsic risk at- titudes from intrinsically risk averse to intrinsically risk seeking or vice versa. This result, although obtained from limited testing, points out the important distinction which must be made between constant intrinsic risk attitude for one decision (that the transformation between u(x) and v(x) is constant), and the idea of an intrinsic attitude towards risk which is constant across situations. The reversal of intrinsic risk attitudes between decisions in Krzysztofowicz's study may be due, in part, to the construction of his experiment. Kahneman and Tversky (1979) have observed that individuals are generally risk seeking in the domain of losses and risk averse in the domain of gains. They argue that the utilities elicited will be influenced by how the questions are framed. The two scenarios analyzed in Krzysztofowicz's experiment can be viewed as two framings of the same outcome space: any outcome above the extremely pessimistic decision could be viewed by the decision maker as a gain while any outcome below the extremely optimistic decision could be viewed as a loss. Slovic, Fischhoff, and Lichtenstein (1982) report that if an outcome representing a monetary loss is framed in terms of an insurance premium rather than a sure loss, a reversal in risk attitude is often observed. 51 Because of the limited nature of the experiment and the possible in- fluence of framing, Krzysztofowicz's results cannot be interpreted as conclusive evidence supporting or rejecting the hypothesis that risk at- titude is independent of the decision context. Therefore, we continue with our hypotheses that: (1) there is some transformation between u(x) and v(x) for a given decision, which encapsulates risk attitude and (2) intrinsic risk attitude is constant across situations and may be termed the individual's intrinsic attitude towards risk. The first hypothesis ad- dresses the question of whether the transformations between utility and value functions reflect actual preferences of decision makers. The second hypothesis addresses the question of whether individuals' intrinsic risk attitudes are independent of the attributes over which their preferences are assessed. This hypothesis seems intuitively plausible since any non- linear transformations between an actual attribute and the value of that attribute are incorporated in v(x) and, therefore, do not enter into the relationship between v(x) and h[v(x)]. [he_Agegyagy_gf the Present Theory 2: Intrinsic Risk Attitude Stiglitz (1969, pp. 664-666) has shown that for constant absolute risk attitudes to be exhibited, all indifference curves must be homothetic and all Engel curves must be straight lines through the origin. Dyer and Sarin, by explicitly separating the effect of non-linear value functions from attitude towards risk have obviated the need for homothetic indifference curves in the development of the concept of intrinsic risk attitude. However, Dyer and Sarin's development of constant intrinsic risk attitude implicitly contains another assumption which is equally troublesome. By using holistic preference judgements, Dyer and Sarin assume that one of the 52 following two conditions hold: (1) that all decision problems are simple value problems, i.e. that outcomes refer to only one attribute, or (2) that preferences for attributes in multiattributed outcomes are independent and additive. Extension agents, farm management specialists and others concerned with decision making in the food and fiber sector know that decision makers are often concerned with multiple attributes of any outcome. A farmer may be concerned not only with maximizing income, but also with his asset/debt ratio, quality of life, maintaining soil productivity, or implications of current decision outcomes for future flexibility in organization of the farm firm. Therefore, if our goal is to develop a measure of attitude towards risk which can be used in predicting preferred action choices for realistic decisions, we cannot assume that each possible outcome of a decision has only one attribute. To do this, we must reconsider the assumption that preferences for attributes in multiattributed outcomes are independent and hence, additive. The assumptions of independence required for additivity are quite strong and easily violated.3 Consider an outcome X with attributes (x1,x2). The assumption of strict independence of attributes required for additivity is, loosely speaking, that preferences for attribute x1 are not influenced at all by the level of attribute x2. The indifference map for this case is shown in Figure 12. Keeney and Raiffa (1976, pp.330-332) show that if preferences over an outcome space for three attributes are compatible with an additive value 3 The independence conditions required for additive and multiplicative value and utility functions will be discussed in detail in Chapter 4. 53 x2 x1 Figure 12: Indifference Curves for Two Attributes which Meet the Independence Conditions Required for Additivity. 54 function and conditions for a multiplicative utility function are met, then the utility function must have one of the following three forms: u(x) is a linear transform of -e'CVix), c > 0 u(x) is a linear transform of v(x) u(x) is a linear transform of eCVixl, c > 0 The second case, analogous to Dyer and Sarin's constant intrinsic risk neutrality, implies that both the value and utility functions are additive. The first and third cases, analogous to Dyer and Sarin's constant intrinsic risk aversion and constant intrinsic risk proneness, imply that the value function is additive and the utility function is multiplicative. Again, the case of a multiplicative value function is not addressed. Development of a more general set of transformations between value and utility functions which allow for cases of additivity or multiplicativity in both value and utility functions is the goal of Chapter 4. It will also be shown that the results obtained for the case when the value function is additive and the utility function is multiplicative are equivalent to those given by Dyer and Sarin and Keeney and Raiffa. CHAPTER 4 A NEH MEASURE OF ATTITUDE TOHARDS RISK Impetus for development of a new measure of attitude towards risk has come from the observations that marginal value of money is not constant, preferences are not homogeneous, and preferences for multiple attributes of outcomes do not necessarily meet the conditions required to assume ad- ditivity of the value or utility function. The first two observations are addressed by the concept of intrinsic risk attitude. The third must be addressed by the use of multi-attribute utility theory as a basis for a new measure of attitude towards risk. The chapter begins with an examination of the independence conditions which are required to be met in order to assume additivity or multi- plicativity of value and utility functions. This is followed by a brief exposition of the aspects of multiattribute utility theory which are per- tinent to the development of the measure of attitude towards risk. This discussion includes some special problems which arise in the current ap- plication and which necessitate the weakening of some of the conditions of independence. The allowable transformations between value and utility functions which form the basis for measuring attitude towards risk are then developed. These results are used in a sample application and then compared to those obtained by Dyer and Sarin in their development of the concept of constant intrinsic risk attitude. 55 56 Ingependence Conditions £2; Additive agg Multiplicative a ue a__ ilit'y Fufitions Using one of several representation theorems, value functions can be constructed which preserve orderings among multiattributed riskless out- comes. The form of the value function (additive or multiplicative) depends upon the degree to which preferences meet certain conditions of independ- ence. Both additive and multiplicative value functions require the condi- tion of mutual preferential independence. Eyeferential Inde ndence: Attribute Y, where Y e X is preierentially pe nt of its complement Y' if the preference order of consequences involving only changes in the levels in Y does not depend on the levels at which attributes in Y' are held fixed. This definition implies that the conditional indifference curves over Y do not depend on the attributes Y'. Mutual Preferential Inde ndence: Preferential independence must also h6ld for attriBuEes in Y' with respect to Y. For a value function to be multiplicative, it is required only that mutual preference independence and weak difference independence hold. Heak Difference Inde ndence: Y is weak difference independ- efit of €53 remaining attributes if the ordering of preferences on Y does not depend on the fixed level of the other attributes. For a value function to be additive, a stronger condition must be met. In addition to mutual preference independence, strong difference independ- ence must hold. 57 Stro Difference Inde ndence: Attribute Y is stron dif- erence IfidEiEfidEfit of ESE remaining attributes i the preference difference between two levels of Y is not af- ected by fixed levels of the other attributes. _ Similarly, additive and multiplicative utility functions can be distin- guished on the basis of the restrictiveness of the independence conditions which preferences meet. Both additive and multiplicative utility functions require that the condition of utility independence is met. Utilit Independence: Attribute Y where Y e X, is utilit ifidEpenden 0 ts complement Y' if the conditiona preference order for lotteries involving only changes in the levels of attributes in Y does not depend on the levels at which the attributes Y' are fixed. For a utility function to be multiplicative, only utility independence and mutual preference independence must h0ld. Additivity of a utility function requires that an additional condition, known as the marginality assumption, holds. Marginality Assu tion: Attributes Y where Y e X are addi- ve ndependen preferences over iotteries on Y depend only on their marginal probability distributions and not on their joint probability distributions. The marginality assumption is sometimes difficult to intuit, but can be made clearer using the following example. The marginality assumption re- quires that for any a 6 Y1 and b 6 Y2, the decision maker is indifferent between lotteries l1 and l2 shown below. /(a’b.) z ‘2 \ (8*,b‘“) (8*Ib) (8.b) /\ SB Multiettribute Velue egg geilley Functions If preferences meet the independence conditions required for additivity discussed above, an additive multiattribute value function is written as: (4.1) v(X) = {Vivmil where v1 is a single attribute value function and w1 is a scaling constant between zero and one.1 If preferences meet the independence conditions required for multi- plicativity, a multiplicative multiattribute value function is written as: (4.2) 1 + wv(x) = “[1 + ww1v1(x1)] where w is a constant reflecting the type and degree of non-additivity present.2 Similarly, if preferences meet the independence conditions required for additivity, an additive multiattribute utility function is written as: (4.3) u(x) = {kiu1(x1) where “i is a single attribute utility function and k1 is a scaling con- stant between zero and one. If preferences meet the independence conditions required for multi- plicativity, a multiplicative multiattribute utility function is written as: (4.4) 1 + ku(x) = fl[1 + kk1u1(x1)] where k is a constant reflecting the type and degree of non-additivity present and must meet the conditions specified for w in footnote 2. 1 Calculation of scaling constants is discussed in Chapter 5. 2 Calculation of w is also discussed in Chapter 5. w must be either -1Sw<0 or w>0 and solve the condition 1 + w = “(I + HHi). 59 Reversals ip_Preferences egg Sign Conditions . The multiplicative value and utility functions defined above do not allow for reversals in preferences over subsets of the attributes. In many situations, we would not expect reversals to occur in an individual's preferences. However, there are important cases where they do seem reasonable. For example, in an agricultural situation, one could expect that preferences for rain to increase or decrease depending on the level of sunshine available. If this occurs, the conditions of preference and utility independence required for multiplicative value and utility func- tions will be violated. It is impossible to have reversals in preference with the additive form of the value and utility functions. The violation of the independence conditions required for multiplicative functions can be avoided by weakening the independence conditions to those of generalized preference independence and generalized utility independence (Fishburn and Keeney, 1974, 1975) . Generalized Preference Indepengence: Y1 is generalized preferentially independent of Y2 if, given any two levels of y2, the two orderings of Y1 are either identical, reversals of each other, or indifference exists among the Y1. Generalized Utility Independence: Attribute Y1, is general- ized utility independent of attribute Y2 if the conditional preference order for lotteries involvin only changes in the evels of attributes in Y1, given any wo levels of y2, are either identical, reversals of each other, or indifference exists among the Y1. Generalized preference independence is also known as sign dependence (Krantz, et al, 1971, pp. 329-332) or the sign axiom (Roskies, 1965). The relationships among independence concepts is shown in Figure 13. 60 MARGINALITY ASSUMPTION UTILITY INDEPENDENCE / GENERALIZED UTILITY INDEPENDENCE PREFERENCE INDEPENDENCE GENERALIZED PREFERENCE INDEPENDENCE STRONG DIFFERENCE INDEPENDENCE I HEAK DIFFERENCE INDEPENDENCE 1. Given y,y',x,x'cX, x preferred to y and x' preferred to y' implies 2. Given X = X1 x X2 x..x Xn for some positive integer n, each X1 is a convex subset of a finite dimensional Euclidean space and: Za(x)u(x) > Xb(x)u(x) iff a is preferred to b for all a,beA holds for some u: X -> Re which is continuous in the rela- tive usual product topology for X. Figure 13: Relationships Among Independence Concepts3 3 Adapted from Fishburn and Keeney (1974, p. 300) 61 It has been noted that either w>0 or -1$w<0. If w is greater than zero and 1 + wv is a multiplicative value function with terms 1 + ww1v1(xi) then v' = a(1 + wv) where a>0 is also a multiplicative value function with terms a1(1 + ww1v1(x1)) where Ia] = a. But if -1Sw<0 and v is the original value function, 1 + wv produces an inverse ordering. However, -(1 + wv) = -fl(1 + wwIV1(Xi)). or: (4.2a) (sgn w)(1 + wv) = (sgn w)n(1 + ww1v1(x1)) Analogous results apply the the multiplicative utility functions so that: (4.4a) (sgn k)(1 + ku) = (sgn k)l( 1 + kk1u1(x1)) These results are used in the proofs of the transformations between value and utility functions. Reference to (4.2) and(4.4) in the following sec- tions will, unless otherwise stated, refer to the forms shown in (4.2a) and (4.4a). Economic Interpretation pf Parameters 5 egg 5 4 Consider the two equal probability lotteries and <8,D> shown in Figure 14 and assume that preferences are increasing in both Y and 2. It will be assumed that the individuals value functions are homogeneous. It can be shown that if is preferred to <8,D>, k)0 and Y and 2 can be viewed as complements, if is indifferent to <8,D>, k=0, indicating an additive utility function and that preferences for Y and Z are independent, while if (8,0) is preferred to , k<0 and Y and 2 can be viewed as substitutes. 4 gzgtg4lgr this section are adapted from Keeney and Raiffa (1976, pp. 62 Z I I I I I l I I I 22 -------- B C I I l 21 -------- A D I I Y1 Y2 Y Figure 14: Using Lotteries to Interpret k in a Multiplicative Multiattribute Utility Function. 63 The lotteries are structured so that for , the individual will either receive a high level of both Y and Z or a low level of both. For lottery <8,D), the individual will receive either a high level of Y or 2, but not a high level of both. If is preferred, it is as if the in- dividual needs an increase in Y to complement and increase in Z in going from A to C. Otherwise, the full worth of the increase in 2 could not be exploited. On the other hand, to prefer <8,D> implies that is important to receive a high level of at least one attribute and, given a high level of, say, Y, the increased preference due to an increase in 2 is not as much. Thus Y and 2 can be thought of as substitutes for each other. To illustrate a complementary case, consider a farm manager who is thinking of investing in the use of a new, pest sensitive, high yielding variety of grain and a new, more expensive pest manageaent system. At- tribute Y can be viewed as the productivity of the new variety on his field, given existing soil types, drainage, etc. Attribute 2 can be viewed as the successfulness of the new pest management system. If both the high yielding variety and the new pest management system are successful, the farm manager is very happy. However, if either fails (the HYV does not flourish on his soil type, or the pest management strategy does not keep away the targeted pests), the financial consequences may be as bad as if both had failed. To illustrate a case of substitution, consider a farm manager who is thinking of using a new variety of corn on two separate fields which have very different soil and drainage characteristics. Attribute Y, in this case, is the yield from one field while attribute Z is the yield from the other. Hhile the farm manager would like it if both fields flourished, achievement of attributes Y and 2 would, most likely, be substitutes. 54 Fischer (1976) sets forth another interpretation for k. He argues that a k>0 could be indicative of complementary attributes, or the simple fact that the individual is willing to give up a sure thing in either attribute for the chance of receiving something which is better with regard to both attributes, i.e. risk proneness. Similarly, a k<0 could indicate attributes which are substitutes or simply an aversion to high variance outcomes. These two interpretations of k are not necessarily contradictory: both can add insight into the formation of attitudes towards risk. If Keeney and Raiffa's interpretation of k is applied to the interpretation of w, then if w>0, the attributes can be said to be complements, and if w<0, the at- tributes can be said to be substitutes. Because a multiattribute utility function, like a von Neumann-Morgenstern utility function, incorporates both attitudes towards risk and information about the individual's value function, examination of k without information about w does not allow us to determine what portion of k is due to the complementarity or sub- stitutability of the attributes and what portion is due to attitude towards risk. Allowable [Lensfggeetions Between Value egg UELLLEy Functions Results which relate value and utility functions can be found scattered throughout the recent literature in measurement theory (e.g. Dyer and Sarin, 1979; Keeney and Raiffa, 1976; von Hinterfeldt, 1979). Further work is needed to exactly define the class of allowable transformations between utility and value functions. In this section we will present proofs of the relationships between measurable value and utility functions. A common way to relate v(x) and u(x) is through the uniqueness theorems of their respec— tive measurement theoretic representations. The proofs presented here 65 differ from many earlier proofs in that we will rely on the use of Cauchy's four fundamental functional equations: this greatly simplifies the proofs and allows us to depart from the standard assumptions about the additivity of the value function. Cauchy was not concerned with decision theory, utility functions, or value functions. Instead, he introduced the first systematic treatment of some basic functional equations to prove the powerful and practical nature of some rather abstract and original concepts he introduced such as the concept of limit and the concept of a continuous function. Cauchy's func- tional equations are applicable to the solution of many problems in economics (Gehrig, 1984). They are used here in a new application. He begin with the general functional equation: (4.5) F[x1,x2,...,xn] = h{G[x1,x2,...,xn]} This general functional equation can be rewritten for the specific cases of additive and multiplicative value and utility functions. For the case where the value and the utility function are additive, a general functional equation can be written as: (4-6) v(xl = luiIXi) = hIIViIXIII = h[VIXl] This is of the same form as the general Cauchy equation: (4-7) h(X) + bi!) = h(x + y) thich, if h is continuous, has the general solution: (4.8) h(r) = ar Similarly, for the case where the value function is additive and the utility function is multiplicative, the functional equation, Cauchy equa- tion, and general solution for the Cauchy equation can be written, respec- tively, as: 66 (4.9) 1 + ku(x) = fl( 1 + kk1u1(x1)) = h[2v1(x1)] = h[v(x)] (4.10) h(x)h(y) = h(x + y) (4.11) h(r) = car. If the utility function is additive and the value function is multi- plicative, the functional equation, Cauchy equation, and general solution to the Cauchy equation can be written, respectively, as: (4-12) "(XI = zIIIIXi) = h[II(1+ WIVIIXilll = h[1+ WOO] (4-13) h(X) + h(r) = h(XY) (4.14) h(r) = a In r If both the utility and value functions are multiplicative, the func- tional equation, Cauchy equation, and general solution to the Cauchy equa- tion can be written, respectively, as: (4.15) 1 + ku(x) = "(1 + kk1u1(x1)) = h[u(1 + ww1v1(xi))] = h[l + wv(x)] (4-16) h(XIhm = h(xv) (4.17) h(r) = r3. The Cauchy equations and their general solutions can be used to solve the general functional equations for the cases of additive and multiplica- tive value and utility functions. The solutions, which can be viewed as the transformation between the utility and value functions, provide the basis for a new measure of attitude towards risk. Each possible case and its solution are given below. Proofs are contained in appendices 4A, 4B, 4C and 4D. Qeee_;: If the value and utility functions are additive, then: (4A.1) u = v Ceee, 2: If the value function is additive and the utility function is multiplicative, then: (48.1) 1+ ku = (1 + k)V 67 Case 3: If the value function is multiplicative and the utility function is additive, then: (4C.1) u = (ln(1 + wv))/(ln(1 + w)) Case g; If the value and utility functions are multiplicative, then: (40.1) 1 + ku = (1+ wv)(I"(1+ k))/(In(1+ w)) Synthesizing end Applying ghe 31133131; It has been shown that there exists a specific set of allowable trans- formations between value functions and utility functions. To envision how these results can be applied in determining an individual's pure or intrin- sic attitude towards risk, consider the individual whose value and utility functions are shown in Figure 15. Assume that the individual's value func- tion is additive and that: (4.18) v1(x1) = ln x1 and that the individual's utility function is multiplicative and that: (4.19) "1(in = (x: -1)(1/ 0 u is a linear transform of v iff b(x) = 0 u is a linear transform of ebVIX) iff b(x) = b < 0 The second case, where b(x) = 0 follows directly from (4A.1). The first and third cases will be examined first for the situation where the value func- tion is additive and the utility function is multiplicative. From Appendix 48, this case can be written as: (48.1) 1 + ku = (1 + k)v or, before standardization, as: (48.7) (sgn k)(1 + ku) = e3(39n k)v 79 Hhen k < 0 and b(x) > 0, indicating risk aversion, (48.7) can be rewritten as: t (4.42) -(1 + ku) = e‘3V or (4.43) u = (-e'av - 1)lk which corresponds to Dyer and Sarin's hypothesis. Similarly, when k > 0 and b(x) < 0, indicating risk proneness, (48.7) can be rewritten as: (4.44) u = (eav - 1)/k which also conforms to Dyer and Sarin's hypothesis. Hhen the value function is multiplicative and the utility function is either additive or multiplicative, however, Dyer and Sarin's hypotheses regarding u are rejected. Therefore, we can conclude that Dyer and Sarin’s hypothesis of constant intrinsic risk aversion hold for the cases when the value function is additive, but not when it is multiplicative. APPENDICES TO CHAPTER 4 80 APPENDIX 4A geee_1: If the value and utility functions are additive, then: (4A.1) u = v Proof: Let Viviixi) = Vi' (Xi) kiUiIXi) = Ui'(Xi)- Assume that for the additive value function (4.1) and the additive utility function (4.3) there exists some continuous function h, such that, from (4.6): (44-2) {Ui'IXIl = hIZVI'IXIII Let x3 = x30 = 0 for all j not equal to i. (4A.2) is reduced to: (48-3) ui'(Xi) = h[Vi'IXii] Substituting the right hand side of (4A.3) into (4A.2) yields: (44 4) ZhIVi'IXill = h[EVi'Otil] Now let x) = x)” = 0 for all i = 3,4,...,n. (44.4) can now be written: (44-5) h[V1'IX1l] + h[V2'(X2)l = h[VI'IXII + v2'(X2)] which is Cauchy's fundamental functional equation from (4.7) with general solution: (4.8) h(r) = ar Substituting (4.8) into (4A.2) yields: (44.6) ZUi'IXI) = aXVI'IXI) Since Eu1'(x)) = u from (4.3) and Ev1'(xi) = v from (4.1), (4A.7) u = av This solution of the functional equation is unique up to the specifica- tion of one parameter, a. To make the solution unique, the free parameter 81 must be “used up“. To do this, choose elements x0, x1 c X such that x1>x0 and defining u(xo) = v(xo) = 0 and u(xl) = v(xl) = 1. x0 and x1 can be viewed, respectively, as the worst and best alternatives available. Solving for a in (4A.6) yields: (4A.8) a =1 Therefore, the standardized equation takes the form: (4A.1) u = v 82 APPENDIX 48 Case 2: If the value function is additive and the utility function is multiplicative, then: (48.1) 1 + ku = (1+k)V Proof: Let H1V1(X1) = V1'(X1) 1 + kkiUiIXi) = UI'IXI) Assume that for the additive value function (4.1) and the multiplicative utility function (4.4) there exists some continuous function h, such that, EI‘OI (4. 9): (48.2) (sgn kIIUI'IXII = h[(sgn k) {Vi'IXIII (48.2) is the compact form of the two functional equations u' = h[v'] for k>0 and -u' = h[-v'] for k<0. Let x5 = x30 = 0 for all j not equal to i. (48.2) is reduced to: (4B 3) (sgn k)Ui'IXI) = h[(sgn k) Vi'IXIil Substitution of the right hand side of (48.3) into (48.2) yields: (48-4) "h[(sgn k) vi'(Xi)] = h[(sgn k) VI'IXIIJ Now let x1 = x19 = 0 for all i = 3,4,...n. (48.4) can now be written: (48-5) h[(sgn k) V1'(X1)]h[(39n kl V2'(X2)] = h[(sgn k) v1'(x1) + (sgn k) v2'(x2)] which is Cauchy's fundamental functional equation from (4.10) with the general solution: (4.11) h(r) = ear 83 Substituting (4.11) into (48.2) yields: (48.6) (sgn k)lu('(x1) = e159" kIXV'IX) Since v1'(x() = v from (4.3) and (sgn k)nu('(x1) = (sgn k)(1 + ku) from (4.4), (45.7) (sgn k)(1 + ku) = e8 (89" kI v Using the standardization conventions adopted in the proof of case 1, and solving for a yields: (48.8) a = ln(1 + k) Therefore, the standardized equation can be written: (45.1) 1 + ku = (1 + k)V 84 APPENDIX 4C Case 3: If the value function is multiplicative and the utility function is additive, then: (4C.1) u = (ln(1 + wv))/(ln(1 + w)) PI‘OOF: Let 1 + ww1v1(x1) = v1'(x1) kiui(XI) = Ui'IXI) Assume that for the multiplicative value function (4.2) and the additive utility function (4.3) there exists some continuous function h, such that, from (4.12): (40-2) (89n V) XUi'IXi) = h[(sgn HIIVI'IXill (4C.2) is the compact form of the two functional equations u' = h[v'] for w>0 and -u' = h[-v'] for w<0. Let x1: x30 = 0 for all j not equal to i. (4C.2) is reduced to: (4c.3) (sgn w) ui'Ixi) = h[(sgn wivi'IxIII Substituting the right hand side of (4C.3) into (4C.2) yields: (40-4) {h[(sgn VIVI'IXIII = h[(sgn w)IIVi'(Xi)] Now let x, = x10 = o for all i = 3,4,...,n. (4c.4) can now be written: (40-5) h[(sgn w)V1'(XI)] + h[(sgn w)V2'(X2)I = h[(sgn w)(v1‘(x1))(69n w)(vz'(xziil which is Cauchy's fundamental functional equation from (4.13) with the general solution: (4.14) h(r) = a In r 85 Substituting (4.14) into (4C.2) yields: (4C.6) (sgn w) Eu1'(x1) = a ln((sgn w) flv1'(x1)) Since (sgn w)uv1'(x1) = (sgn w)(1 + wv) from (4.2) and 2u1'(x1) = u from (4.3), (4C.7) (sgn w) u = a ln((sgn w )(1 + wv)) Using the standardization conventions adopted in the proof of case 1, solving for a yields: (4C.8) a = 1/(ln(1 + w)) and the standardized equation takes the form: (4C.1) u = (ln(1 + wv))l(ln(1 + w)) 86 APPENDIX 40 Case 5: If the value function and utility function are multiplicative, then: (ma)1+m=(1+wHMU+kHMM(1+w) Proof: . Let 1 + wiVi(XII = vi'IXi) 1 + kkiUiIXi) = ui'(Xi) Assume that for the multiplicative value function (4.2) and multiplicative utility function (4.4) there exists some continuous function h, such that, from (4.15): (4D.2)(89n H)(ssn k) Ini'1 attributes at a time). InehRespondents For this preliminary examination of the theory, subjects were recruited from the agricultural technology program at Michigan State University. The agricultural technology program offers a certificate to students after two years of study in technical agriculture. All of the individuals participat- ing in the completion of the questionnaire had farm backgrounds and were enrolled in agricultural economics type courses within the agricultural technology program. This group was selected because of their familiarity with decision making in agricultural settings and the relative ease with which the ques- tionnaire could be administered. Fifty-nine students participated in the study. Ine,Qneetionnaire Participants were given two hours to complete a questionnaire designed to elicit preferences within the context of different agricultural 183 decisions. A total of three decision contexts were used; each participant responded to questions about two of the decisions. Each participant was presented with a booklet containing instructions, descriptions of each decision context and a questionnaire for each decision context. A copy of the complete questionnaire for one decision context, that of selecting a variety of feed corn, can be found in Appendix 5A. The format of the questionnaire has been changed slightly due to page width restrictions.3 The content is identical to that presented to the respon- dents. Descriptions of the other two decision contexts are contained in Appendix 58. The questions for these decision contexts are functionally equivalent to those contained in Appendix 5A. The questionnaire was designed to elicit several types of information including preference conformance with independence conditions, single attribute value and utility functions, and the scaling constants required to convert the single attribute functions into multiattribute functions. After reading the instructions, each student was presented with a description of their first decision context. The respondents were first asked to respond to a series of questions (ll-I4) designed to test whether preferences met the condition of general- ized preference independence required for either an additive or a multi- plicative value function. Preference for one variety over another In each case constitutes satisfaction of the condition of generalized preference independence. 3 Specifically, much of the text which was double spaced in the actual questionnaire is single spaced in the Appendix. In addition, scales used to elicit value functions In questions 12-14 have been compressed in the Appendix. 184 The next series of questions (IS-I7) checked for the presence of strong difference independence required for an additive value function. In each case, if the response for part (a) is identical to the response to part (c) and the response to part (b) is identical to the response to part (d), the individual is said to exhibit strong difference independence between the two attributes whose values change in the question. Since the existence of an additive or multiplicative value function does not necessarily imply that the utility function meets the same condi- tions, generalized utility independence and the additional condition for an additive utility function, known as the marginality condition must also be checked. Questions 8-10 check for the existence of generalized utility independ- ence. If the condition holds, responses to parts (b) and (c) are Ino“. Question 11 tests for satisfaction of the marginality condition required for an additive utility function. Respondents should be indifferent for (a), (b), and (c) if this condition holds. The next step is to elicit value functions for each of the attributes using a mid-value splitting technique. Because this technique may be dif- ficult to understand, these questions are prefaced with an example. In the example and the representative question, the first response yields v(x)=.5, where x is the attribute in question, the second response yields v(x)=.25 and the third response yields v(x)=.75. Questions 12—14 elicit the value functions for the individual attributes. Univariate value functions are only one of the two types of information needed to determine a multiattribute value function. The second type, information needed to determine scaling factors, is elicited using ques- tions 15(a), (b) and (c). The first question in each part elicits 185 information needed to determine the scaling constants using extreme values: the second question elicits the information needed to determine the scaling constants using non-extreme values. Univariate utility functions are then elicited for each attribute in questions 16-18. In each question, the first response yields u(x)=.5, the second response yields u(x)=.25, the third response yields u(x)=.75 and the fourth response is a consistency check for u(x)=.5. The final series of questions elicit the information needed to deter- mine the scaling factors to convert the univariate utility functions into a multiattribute utility function. Because this technique also may be dif- ficult to understand, the questions are prefaced with an example. As with the scaling constants for the value function, the first questions elicits probabilities using extreme values while the second question uses non- extreme values. After responding to a functionally equivalent set of questions for the second decision context, respondents are asked to indicate their agricul- tural background and experience in making decisions in contexts similar to those presented in the questionnaire. Most respondents took from one hour to one and a half hours to answer the set of questions for the first decision context and about one-half hour to answer the set of questions for the second decision context. Problems H1§n_tne_9nestionneire Decision theory has often be criticized by those interested in applied problem solving because of the cost, time and difficulties involved in obtaining reliable information with which to determine an individual's utility function. This study was not exempt from these difficulties. 186 Previous published studies which have obtained either an individual's multiattribute value or utility function for one decision have stressed the time involved to familiarize the respondent with the parameters of the decision and the techniques to be used in the elicitation of their utilities. Then the researcher or ”decision analyst“ works through the series of questions with the respondent, giving him or her constant feed- back on the consistency and implications of their responses. If mathemati— cal consistency is not obtained with their original responses, respondents are asked to reconsider and modify their responses until consistency is reached. For instance, when Keeney (1972) elicited the multiattribute utility function of a blood bank administrator for two attributes, shortage and outdating of supplies, he spent ”several afternoons" completing these steps. In contrast to these previous studies, the participants involved in this study were asked to complete a questionnaire which elicited informa- tion required to determine two multiattribute value functions and two multiattribute utility functions in only two hours. Although written and verbal explanations were given for the questions which were anticipated to present problems (the mid-value splitting technique for determining single attribute value functions and the probabilistic questions for determining scaling constants for multiattribute utility functions), they completed the questionnaires without feedback from the researcher. In addition, there were few formal or informal consistency checks. Table 2 shows that many of the individuals had difficulty understanding some of the questions and hence, their questionnaires were not usable for further analysis. 187 lable 2: Number of Individuals Hho Had Difficulty Answering Specific Types of Questions. I'Iype pf Question Number g£_Individuals I I I I Mid-Value Splitting 25 I l Certainty Equivalent 11 l I Certainty Scaling4 1 I I Probabilistic Scaling4 23 I l Satisfaction pf Independence Congjtions Although many of the responses were not usable for a complete analysis because of problems in responding to the questions noted in Table 2, almost all were usable to determine the degree to which independence conditions required for either additive or multiplicative multiattribute utility and value functions were met. The summary statistics for those individuals whose responses met the independence conditions are shown in Table 3. The statistics are compiled by decision context, not by individual. Since some individuals only completed the first half of the questionnaire, the same number of responses were not available for each decision context. Table 3: Number of Responses Satisfying Independence Conditions | Decision Context I Independence Condition Variety Dryer Loan I Generalized Preference Independence 39 39 34 I Strong Difference Independence 4 12 5 Generalized Utility Independence 18 17 17 Marginality Condition5 9 10 a i 4 The first part of these questions do not use responses to earlier questions. If these were answered reasonably, the individual was regarded to have understood the question. 5 Only those responses for which generalized preference independence was met are included in statistics for the marginality condition. 188 Those responses for which generalized utility independence was not met are not usable as this preference condition is required for either an additive or a multiplicative utility function. Several interesting points can be made by observing the frequency of additive or multiplicative value and utility functions in those decision context responses in which the condition of generalized utility independ- ence was met. Tables 4 and 5 contain the summary statistics for the usable responses where the condition of generalized utility independence was met. Again, these summary statistics are by decision context, not by numbers of individuals. The reader will recall that the use of Dyer and Sarin's transformations between value and utility functions implicitly requires, in all cases, that the value function is additive. The utility function may be either additive or multiplicative. It can be noted from Table 4 that only nine out of the fifty value functions examined meet this requirement. Table 4: Frequency of Additive and Multiplicative Value and Utility Functions by Decision Context. Decision Context Combination Rele, Variety Dryer Lgen Value Function Additive 2 4 3 Multiplicative 15 12 14 Utility Function I Additive 8 11 8 I Multiplicative 9 5 9 For intrinsic risk neutrality to hold within Dyer and Sarin's framework, both the value and utility functions must be additive. Table 5 shows that only four of the cases examined meet this requirement. Five of the cases meet Dyer and Sarin's implicit condition for intrinsic risk 189 proneness or aversion, that the value function is additive and the utility function is multiplicative. The remaining 41 cases can not be analyzed within Dyer and Sarin's framework. However, they should be capable of analysis using the transformations developed in Chapter 4. Table 5: Frequency of Combinations of Different Types of Value and Utility Functions by Decision Context. | Decision Context | Combination Variety Dryer Lgen Additive Value and Additive Utility 1 1 2 Additive Value and Multiplicative Utility 1 3 1 Multiplicative Value and Additive Utility 7 10 6 Multiplicative Value and | Multiplicative Utility 8 2 8 I l I Ine_Ieene,gfi Consistency g£_Respgnses The only formal consistency test conducted in the questionnaire was an additional indifference question for each single attribute utility function where the respondent was asked to specify u(x)=.5 as a function of the extreme levels of the attribute and as a function of the levels of the attribute where u(x')=.75 and u(x")=.25. If the responses to the two questions were identical, the respondent was assumed to be giving consis- tent responses to that utility function elicitation question. An additional, informal consistency test can be made by examining the responses to the two sets of questions used to determine each scaling constant. The reader will recall from the earlier discussion of the ques- tionnaire that each respondent was asked functionally equivalent sets of indifference questions using extreme values and then non-extreme values of the attributes. In none of the cases examined were the responses identical 118 for the extreme and non—extreme questions. This may be due, in part, to the aforementioned difficulty that individuals have in responding to extreme value type questions. However, the issue of consistency is not so easily dismissed. It is, in fact, quite important in reviewing the responses to the questionnaires. To determine the scaling constants needed to aggregate the single attribute value functions into an additive value function, an overidentified system of simultaneous equations was used. This system of equations can be writ- ten: (5.6) w1v1(x1') = wz (5.7) w2v2(x2') = w3 (5.8) wavaixa') = v: where x(' is the individuals response to the indifference question and vi(x1') can be determined from the individual's value function over at- tribute i. The fourth equation for an additive value function constrains the values of the wi's so that: (5.9) w1 + w2 + w3 = 1 For a solution to be found for the subsystem of equations (5.6), (5.7) and (5.8), the following must hold: (5.33) v1(x1') * v2(x2') * V3(X3') = 1 If this condition does not hold, a convergent solution for the system of equations can not be found. Analogous arguments hold for the systems of equations needed to find the scaling factors for multiplicative value functions and both additive and multiplicative utility functions. 111 For the cases examined, the value of equation (5.33) ranged from .125 to 1.225. No set of responses met the condition set forth in (5.33), that lvi(x(') = 1. The initial conclusion which can be reached from this finding is that the subjects responses are, in some way, 'inconsistent'. However, with the data available from the questionnaires it is not possible to determine the cause of this inconsistency. The central issue is whether the inconsis- tencies in responses are due to fuzzyness in human cognition, e.g. the inability of respondents to accurately educe their preferences, or whether the preference model used is not appropriate. If the apparent inconsistency is due to fuzzyness in human cognition, the problem can be remedied by continuous feedback from the researcher .to the respondent causing the respondent to modify their answers until mathe- matical consistency is obtained. An alternative approach would be to ask the same series of questions in numerous guises, determine the distribution of responses for each xi', and then take the mean as the 'true' value. Hith the data available from the questionnaire, it is impossible to determine the type of distribution of possible 'fuzzy' responses or whether the responses are even near the mean or in either the right or the left tail of the distribution. However, before this approach can be justified in another data collec- tion effort, several other questions must be answered. Perhaps most dis- turbing is the question of how far the researcher can go in forcing mathe- matical consistency and still reflect the true preferences of the respon- dent. Although respondents apparently met the independence conditions for additivity or multiplicativity of their multiattribute value and utility functions (determined through responses to questions 1-11), their 112 preferences may not, in fact, be accurately reflected by either. the addi- tive or multiplicative model. The problem of 'inconsistency' of responses has been discussed by several researchers. Interesting work has been done in this area by Kah- neman and Tversky (1979, 1982), who have demonstrated that apparent incon- sistencies in responses are due to violations of the behavioral content of the axioms of the expected utility hypothesis stemming from human cognitive processes. Perhaps the most well known of these factors is framing, the effects arising when the same alternatives are evaluated in relation to different points of reference. Ellsberg (1961), in a test of the Savage axioms of expected utility, asked several eminent decision theorists to answer a series of questions to determine whether their preferences vio- lated the axioms. He found that the respondents fell into three groups: those who were careful to calculate their responses in accordance with the axioms of the expected utility hypothesis and, thus, gave consistent responses; those who claim to be expected utility maximizers but whose responses were inconsistent, and: those who gleefully gave inconsistent responses. Ellsberg's report (1961, pp. 655-656) of their responses brings levity to this important issue: “...You might now pause to reconsider your replies. If you should repent of your violations -- if you should decide that your choices implying conflicts with the axioms were “mistakes“ and that your 'real' preferences, upon reflec- tion, involve no such inconsistencies - you confirm that the Savage postulates are, if not descriptive rules for you, your normative criteria in these situations. But this is by no means a universal reaction; on the contrary, it would be exceptional. Responses do vary. There are those who do not violate the axioms, or say they won't, even in these situations (e.g. G. Debreu, R. Schlaiffer, P. Samuelson); such subjects tend to a ply the axioms rather than their intuition, and when in dou t, to apply some form of the Principle of 113 Insufficient Reason. Some violate the axioms cheerfully, even with gusto (J. Marschak, N.Dalkey); others sadly but persistently, having looked into their hearts, found con- flicts with the axioms and decided, in Samuelson's phrase, to satisfy their preferences and let the axioms satisfy themselves. Still others (H. Raiffa) tend, intuitively, to violate the axioms but feel guilty about it and go back into further analysis. The Important finding is that, after rethinking all their 'offendinp' decisions in the light of the axioms a number of peop e who are not only sophisticated but reasonable decide that they with to persist in their choices. This includes people who previously felt a “first- order commitment“ to the axioms, many of them surprised and some dismayed to find that they wished, in these situations, to violate the Sure-thing principle. Since this group in- cluded L.J. Savage, when last tested by me (I have been m reluctant to try n again), it seems to deserve respectful consideration.“ Ellsberg goes on to state, in his conclusions (ibid., p. 669): "...Are they foolish? It is not the object of this paper to judge that. I have been concerned rather to advance the testable propositions : (1) certain information states can be meaningfully identified as highly ambiguous; (2) in these states, many reasonable people tend to violate the Savage axioms with respect to certain choices; (3) their behavior is deliberate and not readily reversed upon reflection: (4) certain patterns of 'violating' behavior can be distin- guished and described in terms of a specified decision rule.“ Hithout knowledge of the source of the apparent inconsistency in responses, a formal empirical test of the theory presented in Chapter 4 can not be completed. However, several points have been brought to light which can provide the basis for further research in this area. First is the finding that, although previous work on multiattribute value functions has assumed the existence of an additive value function, only nine of the fifty value functions examined meet this requirement. Second is the finding that, even though forty—nine of the fifty respondents have preferences which appear to satisfy the weaker independence conditions required for a 114 multiplicative multiattribute value function, none of the responses were able to be analyzed fully because of inconsistent responses to questions designed to provide the information necessary to determine scaling con- stants. Because consistency checks were not incorporated throughout the questionnaire, it is not possible, at this juncture, to determine whether the inconsistencies are due to the inability of respondents to accurately educe their preferences or whether the preference model used is not ap- propriate. Resolution of these issues must precede an empirical test of the theory. They are discussed in greater detail in Chapter 6. APPEMDICES TO CHAPTER 5 115 APPENDIX 5A INSTRUCTIONS As you know, agricultural economists are often called upon to make exten- sion recommendat ons, analyze the impact of farm policy and predict the impact of future events on the agricultural sector. One of the pieces of information which is often used in carrying out these tasks is some measure of peoples' attitudes towards risk. Unfortunately, the methods we now use to gather this information are not very good. Therefore, our analyses are often not as good as we would like the: to be. Hith better information, agricultural economists can do better wor . As part of the research project required for a Ph.D. in agricultural economics, I have developed a new measure of attitudes towards r sk which I think is better than the ones that are now used. But before I can convince anyone else that the new measure is better, I have to test it. By consent- ing to participate in this study by completing a questionnaire, you will help me in doing a pilot test of the new measure. In this questionnaire, you will be asked to answer the same series of questions about two different hypothetical decisions. In each case, you will first be given a description of the decision which you are being asked to make. This is followed by a series of questions relating to that deci- sion. Many of the questions may appear to be repetitive, but each is in- cluded for a specific reason. You will be able to answer some of the ques- tions without much thought, while others will be more difficult. This is not an exam, so take your time and think about the questions; there are no right or wrong answers. If there is something you do not understand, please ask me and I will try to explain. The questionnaire packet will take about two hours to complete. You will not be penalized in any way if you decide during the two hours that you cannot complete the entire questionnaire. If, before you start, you feel that you will not be able to complete the entire questionnaire because of the length of time involved, I would appreciate it if you would let me know. To test the theory, complete questionnaires are needed. To confirm that you freely consent to participate in the study, please sign you name on the line below. Your name will not be used in any part of the study. All of your answers will be treated with strictest confidence and you will remain-anonymous. 116 If you are curious as to what your responses indicate about your attitude towards risk, I would be happy to send you the information which results from your questionnaire packet. If you would like to receive this informa- tign, please write your address under your name below. This is purely op ona . I freely consent to participate in this study (please sign here) Thank you very much for agreeing to participate in this study. Beverly Fleisher For this decision situation, imagine that you have just been to talk with the local seed dealer about the variety of feed corn to plant this year. You have already decided that you want to use a 101-107 day long maturing variety. He has told you about several varieties which fit this require- ment, but differ with regard to three other important characteristics. Seed 117 SELECTING A VARIETY OF CORN for all of the varieties costs the same amount. 1. Potential Yield which, for the varieties you are consider- ing, ranges from 100 to 120 bushels per acre, depending on the variety selected. Field Losses which are due to pests (both insect and dis- ease) an nd Iod dging. For the varieties you are considering, field losses range from 0 to 20$ of potential yield, depend- ing on the variety selected. Nitrogen Reguirements which, in the form of anhydrous am- monia, range from 150 to 200 pounds per acre, depending on the variety selected. 118 Suppose you must make choices between two varieties at a time. The five varieties the seed dealer told you about have the characteristics shown below. Variety Variety Variety Variety Variety Characteristics 1 g g 4, § Potential Yield (in bushels/acre) 100 110 110 110 100 Field Losses (as I of yield) 51 51 15$ 15$ 15: Nitrogen Requirement (as lb./acre) 175 175 175 200 200 (1) In a choice between variety 1 and variety 2, would you (check one): ______ prefer variety 1 to variety 2? ______ prefer variety 2 to variety 1? ______ be indifferent between the two varieties? (2) In a choice between variety 2 and variety 3, would you (check one): _ ____ prefer variety 2 to variety 3? ______ prefer variety 3 to variety 2? ______ be indifferent between the two varieties? (3) In a choice between variety 3 and variety 4, would you (check one); ______ prefer variety 3 to variety 4? ,______ prefer variety 4 to variety 3? _______be indifferent between the two varieties? (4) In a choice between variety 4 and variety 5, would you (check one): ______ prefer variety 4 to variety 5? __*____prefer variety 5 to variety 4? be indifferent between the two varieties? 119 (5) Now suppose that you are aware of a variet with the characteristics shown under the heading variety 1 below and that here exists another group of varieties which have different potential yields and different percentage of field loss. In each of the four cases described below, please indicate theiegiegd loss you would accept to have the higher potential yield of var y . Characteristic Veeiety L Veglety a Potential Yield 100 110 Field Losses 5% ? Nitrogen Requirement 175 175 (a) I would accept a i field loss from variety 2. Characteristic Vegiety I Vegiety_g Potential Yield 100 110 Field Losses 10! ? Nitrogen Requirement 175 175 (b) I would accept a 1 field loss from variety 2. Characteristic !§21221.1 Vegleiy g Potential Yield 110 120 Field Losses 5% ? Nitrogen Requirement 175 175 (c) I would accept a 1 field loss from variety 2. Characteristic !§£1££!.L yeelegy g Potential Yield 110 120 Field Losses 10$ ? Nitrogen Requirement 175 175 (d) I would accept a : field loss from variety 2. 120 (6) Now suppose that you are aware of a variety with the characteristics shown under the heading variety 1 below and that there exists another group of varieties which have different percentage of field loss and different nitrogen requirements. In each of the four cases described below, please indicate the required nitrogen per acre you would accept to have the lower field loss of variety 2. Characteristic Vegiety L Veglety,g Potential Yield 110 110 Field Losses 15$ 5% Nitrogen Requirement 150 ? (a) I would accept a ___“_____lb/acre nitrogen requirement for variety 2. Characteristic 2m ;_ V_a_r;i_e_i_:y_ _2_ Potential Yield 110 110 Field Losses 15$ 5% Nitrogen Requirement 175 ? (b) I would accept a lblacre nitrogen requirement for variety 2. Characteristic yee1e31,1 Veeiety_2 Potential Yield 110 110 Field Losses 10$ 51 Nitrogen Requirement 150 ? (c) I would accept a lblacre nitrogen requirement for variety 2. Characteristic Vegiety_1 Vegiety g Potential Yield 110 110 Field Losses 10$ 5% Nitrogen Requirement 175 ? (d) I would accept a lblacre nitrogen requirement for variety 2. 121 (7) Now suppose that you are aware of a variety with the characteristics shown under the heading variety 1 below and that there exists another group of varieties which have different potential yield and different nitrogen requirements. In each of the four cases described below, please indicate the potential yield you would require to to have the increased nitrogen requirement of variety 2. Characteristic Veeiety,1 Vegiety g Potential Yield 100 ? Field Losses 10$ 10% Nitrogen Requirement 175 200 (a) I would need a bu/acre potential yield from variety 2. Characteristic Men 1 ' V_ai_1ei_:y_ g Potential Yield 110 ? Field Losses 10$ 10% Nitrogen Requirement 175 200 (b) I would need a bu/acre potential yield from variety 2. Characteristic EerieEy 1 Y§£1££1.Z Potential Yield 100 ? Field Losses 10$ 10% Nitrogen Requirement 150 175 (c) I would need a _____"__ bu/acre potential yield from variety 2. Charecteristic Veeiety_1 Veeieey_g Potential Yield 110 ? Field Losses 10% 101 Nitrogen Requirement 150 175 (d) I would need a bu/acre potential yield from variety 2. 122 (8) Now imagine that you are choosing between two varieties, but that you do not have complete information about them. You know the potential yield and field losses for variety 1, but you do not know its nitrogen require- ments. The seed dealer does not know the exact nitrogen requirements of variety 2, but can tell you that that it has a 50% chance of having the characteristics shown in the first column under variety 2, and a 50$ chance of having the characteristics shown in the second column under variety 2. Nhat level of nitrogen requirement for variety 1 would make you indifferent between the two varieties? Variety 1 Variety 2 Characteristiee 59} chance §§$ chance Potential Yield 110 110 110 Field Losses 10$ 10$ 10% Nitrogen Requirement ? 200 150 (a) A lblacre nitrogen requirement for variety 1 would make me indifferent between the two varieties. (b) Hould your answer change if you knew that the potential yield for both varieties was 120 bu/acre? no ______"__yes (c) Nould your answer change if you knew that the field losses for both varieties was 20%? no yes 123 (9) Now imagine that you are choosing between two varieties, but that you do not have complete information about them. You know the potential yield and nitrogen requirements for variety 1, but you do not know its field losses. The seed dealer does not know the exact field losses for variety 2, but can tell you that that it has a 50% chance of having the characteris- tics shown in the first column under variety 2, and a 50% chance of having the characteristics shown in the second column under variety 2. Hhat level of field losses from variety 1 would make you indifferent be- tween the two varieties? Variety 1 Variety 2 Characteristics §9§ chance 5e; chance Potential Yield 110 110 110 Field Losses ? 10$ 20% Nitrogen Requirement 175 175 175 (a) A i field loss from variety 1 would make me indifferent be- tween the two varieties. (b) Hould your answer change if you knew that the potential yield for both varieties was 120 bu/acre? no yes (c) Vould your answer change if you knew that the nitrogen requirement for both varieties was 200 lblacre? no yes 124 (10) Now imagine that you are choosing between two varieties, but that you do not have complete information about them. You know the nitrogen require- ments and field losses for variety 1, but you do not know its potential yield. The seed dealer does not know the exact potential yield requirements of variety 2, but can tell you that that it has a 50% chance of having the characteristics shown in the first column under variety 2, and a 501 chance of having the characteristics shown in the second column under variety 2. Nhat level of potential yield for variety 1 would make you indifferent between the two varieties? Variety 1 Variety 2 Characteristics SQ} chance §Qfi chance Potential Yield ? 100 120 Field Losses 101 ‘ 10$ 10% Nitrogen Requirement 175 175 175 (a) A bu/acre potential yield for variety 1.would make me indif- ferent between the two varieties. (b) Hould your answer change if you knew that the field losses for both varieties was 201? no yes (c) Vould your answer change if you knew that the nitrogen requirement for both varieties was 200 lblacre? no we--.— yes -“—--_ 125 (11) Now imagine that you are choosing between two varieties; you are not sure of the characteristics of each variety, but know that it has a 501 chance of having the characteristics listed in the first column under that variety, and a 501 chance of having the characteristics listed in the second column under that variety. For each of the three pairs of varieties below, you will indifferent between them. Variety 1 Characteristics §g$ chance §ex chance Potential Yield 120 100 Field Losses 20$ 10% Nitrogen Requirement 175 175 (a) Nould you (check one): prefer variety 1 to variety 2? prefer variety 2 to variety 1? be indifferent between the two varieties? Variety 1 Characteristics 59} chance 59} chance Potential Yield 110 110 Field Losses 20$ 10! Nitrogen Requirement 200 150 (b) Hould you (check one): prefer variety 1 to variety 2? ___.__ prefer variety 2 to variety 1? be indifferent between the two varieties? be asked if you prefer one to the other, or if you are Variety 2 §9$ chance, Se} chance 120 100 10$ 20% 175 175 Variety 2 §Qfi ehance §Qfi chance 110 110 10$ 20% 150 200 126 Variety 1 Variety 2 Qneeacteristics 59} chance 59? chance SQ} chance SQ} chance Potential Yield 120 100 120 100 Field Losses 10$ 10$ 10$ 10% Nitrogen Requirement 200 150 150 200 (c) Nould you (check one): prefer variety 1 to variety 2? prefer variety 2 to variety 1? be indifferent between the two varieties? 127 An Example to Help in Answering Questions 12, 13, and 14 Suppose I am to be given a fruit basket with bananas, apples and oranges. I know that the number of bananas in the basket is constant, but that there is some flexibility in the number of oranges and the number of apples in the basket. I am asked to specify a number of apples, A, such that I would give up the same number or amount of oranges to move from 0 apples to A apples as from A apples to 10 apples. 1 really like apples and am not too fond of oranges, although I occas- sionally like to eat them. I decide that I would give up alot of oranges, say 8 of them, to move from 0 apples to 4 apples and another 8 oranges to move from 4 apples to 10 apples. For me, then, A would be 4. I would mark this on the line below as: 0 1 2 3 4 5 6 7 8 9 10 I also put my answer, A, on the line below. Now, I am asked to specify another amount of apples, B, such that I would give up the same number of oranges to move from 0 apples to B apples as from B apples to A apples. I decide that I would give up 3 oranges to move from 0 apples to 3 apples and another 3 oranges to move from 3 apples to A, which is 4 apples. Note that the number of oranges I used in answering to the second question did not have to be the same I used in answering the first. I mark my answer on the line below as B. 128 Now I am asked to specify another amount of apples, C, such that I would give up the same number of oranges to move from A apples to C apples as from C apples to. 10 apples. I begin by marking my response, A, from the first question on the line below. I then decide that my response to this question is 8 apples. I also mark this on the line below. 0 1 2 3 4 5 6 7 B 9 10 I then record my answers at the bottom of the page in the space provided. (a) A = apples (b) B = ________ apples (c) C = apples Questions 12, 13, and 14 ask you to answer questions about the corn varieties that are like this question. Feel free to refer back to this example if you have trouble understanding how to answer. 129 (12) Suppose the nitrogen requirement is the same for all of the varieties you are considering. Please specify the potential yield (in bulacre), A, such that you would accept the same increases in field losses to move from 100 bulacre to A bulacre as from A bulacre to 120 bulacre. Please mark your response on all three of the lines below as A. 1?0 1?1 1?2 1?3 1?4 1?5 1?6....1}3 114 115 116 117 118 119 120 ___—___ _____________|_ POTENTIAL YIELD (in bulacre) Now please specify the potential yield, B, such that you would accept the same increases n field losses to move from 100 u/acre to B as from B bulacre to A bulacre (which you have marked on the line below). Mark your response to this question on the line below as B. 1?0 1?1 1?2 1?3 1?4 105 1?6....1}3 114 115 116 117 118 119 120 ___ ___ ___ ___ ___|___ .... ___ ___ ___ ___ ___ ___ ___ POTENTIAL YIELD (in bulacre) Check to make sure that your response, A, is also marked on the line below. Now, please specify the potential yield, C, such that you would accept the same increases in field losses to move from A bulacre (which you have marked on the line below) to C bulacre as from C bulacre to 120 bulacre. Hark your response to this question on the line below as C. 1?0 1?1 1?2 1?3 1?4 1?5 1?6....1}3 114 115 1:6 117 118 119 120 POTENTIAL YIELD (in bulacre) Please write your responses below: (a) A = bulacre potential yield. (b) B = bulacre potential yield. (c) C = bulacre potential yield. 130 (13) Now suppose that the field losses are the same for all of the varieties you are considering. Please specify the pounds of nitrogen per acre, 0, such that you would require the same increase in potential yield to move from applying 150 lblacre to applying D as you would to move from applying 0 lblacre to 200 lblacre. Please mark your response on all three of the lines below as D. 150 155 160 165 ..... 185 190 195 200 I___l___i___l___l___|___l ----- |___l___|___l___|___|___l NITROGEN REQUIREMENT (in lblacre) Now please specify the pounds of nitrogen per acre, E, such that you would require the same increase in potential yield to move from applying 150 lblacre to applying E as you would to move from applying E lblacre o D lblacre (which you have marked on the line below). Mark your response to this question on the line below as E. 150 155 160 165 ..... 185 190 195 200 l___l___l__.l___l___l__.l ----- l___|__Hl___|___l___I___I NITROGEN REQUIREMENT (in lblacre) Check to make sure that your response, 0, is also marked on the line below. Now, please specify the pounds of nitrogen per acre, F, such that you would require the same increase in potential yield to move from applying D lblacre (which you have marked on the line below) to F lblacre as to move from applying F lblacre to applying 200 lblacre. Mark your response to this question on the line below as F. 150 155 160 165 ..... 185 190 195 200 NITROGEN REQUIREMENT (in lblacre) Please write your responses below: (a) D = ____ lblacre nitrogen requirement. (b) E = lblacre nitrogen requirement. (c) F = _____lb/acre nitrogen requirement. 131 (14) Now suppose that all of the varieties you are considering require the same application of nitrogen per acre. Please specify the field losses, 6, such that you would require the same increase in potential yield to move from 0i field losses to 6% field losses as you would to move from 6! field losses to 20% field losses. Please mark your response on all three lines below as G. o 1 2 3 4 5 6....13141516171819 20 I_i__l__i_l_l_I-.-.l___l__l_l_l_l_l___l FIELD LOSSES (in 1) Now please specify the field losses, H, such that you would require the same increase in potential yield to move from 01 field losses go H! field losses as you would to move from Ht field losses to 61 field losses (which you have marked on the line below). Mark your response to this question on the line below as H. 0 1 2 3 4 5 6....13 14 15 16 17 18 19 20 |__|_|_|__|__|._._l---- |_|__l__l_|_l__.l__l FIELD LOSSES (in i) Check to make sure that your response, 6, is also marked on the line below. Now, please specify the field losses, I, such that you would require the same increase in potential yield to move from 61 field losses (which you have marked on the line below) to It field losses as you would to move from 1% field losses to 20$ field losses. Mark your response to this question on the line below as I. 0 1 2 3 4 5 6....13 14 15 16 17 18 19 20 |_I_I___|____i___l_l---- |__|___l___|_|___l_._l_._.l FIELD LOSSES (in 1) Please write your responses below: (a) G = ____"__, 1 field losses. (b) H (C) I 1 field losses. t field losses. 132 Some of your responses from questions 12, 13, and 14 will be needed to answer question 15. Please transfer them from the previous pages to the spaces provided below. B = potential yield C = potential yield E = _, nitrogen required F = _.__ nitrogen required H = 1 field losses I = 1 field losses (15a) Hhat level of potential yield for variety 1 would make you indif- ferent between variety 1 and variety 2 whose characteristics are shown below? Cheeecteristics Veeiety_1 Vegiegy,2 Potential Yield ? 100 Field Losses 201 01 Nitrogen Requirement 200 200 bulacre potential yield for variety 1 would make me indifferent between the two varieties. Please write your answers for B, H, and I in the appropriate spaces below. Then answer the question: what level of potential yield for variety 1 would make you indifferent between the varieties shown below? Characteristics Vegje§y_1 Vegiety,2 Potential Yield ? B = ______ Field Losses I = __1 H = ___1 Nitrogen Requirement 200 200 bulacre potential yield for variety 1 would make me indifferent between the two varieties. 133 (15b) Hhat level of nitrogen per acre required for variety 1 would make you indifferent between variety 1 and variety 2 whose characteristics are shown below? Characteristics Va_riei_:y_ 1_ V__a_r_i_et_y_ 2 Potential Yield 100 120 Field Losses 201 201 Nitrogen Requirement ? 200 lblacre nitrogen required for variety 1 would make me indifferent between the two varieties. Please write your answers for B, C, and F in the appropriate Spaces below. Then answer the question: what level of nitrogen per acre required for variety 1 would make me indifferent between the two varieties? Mastmeristics 1:21:11 1 11119.21 2. Potential Yield 8 = ____, C = ______ Field Losses 201 201 Nitrogen Requirement ? F = lblacre nitrogen required for variety 1 would make me indifferent between the two varieties. 134 (15c) Hhat level of field losses for variety 1 would make you indifferent between variety 1 and variety 2 whose characteristics are shown below? Characteristics VegieEy 1 Veeiety 2 Potential Yield 100 100 Field Losses ? 201 Nitrogen Requirement 200 150 1 field losses for variety 1 would make me indifferent between the two varieties. Please.write your responses for E, F, and I in the appropriate spaces below. Then answer the question: what level of field losses for variety 1 would make me indifferent between the two varieties? Characteristics Vegiety,1 Vegjety,2 Potential Yield 100 100 Field Losses ? I = _____1 Nitrogen Requirement F = E = _____ 1 field losses for variety 1 would make me indifferent between the two varieties. 135 In questions 16, 17, and 18, notice that variety 2 has a 501 chance of having the characteristics shown in column 1 and a 501 chance of having the characteristics shown in column 2 under the heading variety 2. (16a) Please specify the sure amount of field losses, J, for variety 1, that would make you indifferent between variety 1 and variety 2 with the characteristics shown below Characteristics Variety 1 591 QEQEEEFY 2 §e1 EhéflSQ. Potential Yield 100 100 100 Field Losses ? = J1 01 201 Nitrogen Requirement 200 200 200 J = , 1 field losses (16b) Please also fill in your answer for J in the table below. Then specify the sure amount of field losses, T, for variety 1, that would make you indifferent between variety 1 and variety 2 with the characteristics shown below. Variety 1 Variety 2 Characteristics 591 chance 591 chance Potential Yield 100 100 100 Field Losses ? = T1 01 J = Nitrogen Requirement 200 200 200 T = 1 field losses 136 (16c) Please fill in your answer for J in the table below. Then specify the sure amount of field losses, L, for variety 1, that would make you indif— ferent between variety 1 and variety 2 with the characteristics shown below. Variety 1 Variety 2 Characteristics 591 chance 591 chance Potential Yield 100 100 100 Field Losses ? = L1 201 J = _ Nitrogen Requirement 200 200 200 L = 1 field losses (16d) Please fill in your answers for T and L in the table below. Then specify the sure amount of field losses for variety 1 that would make you indifferent between variety 1 and variety 2 with the characteristics shown below. Variety 1 Variety 2 99eracteristics 591 ehance 591-chance Potential Yield 100 100 100 Field Losses ? T = 1 L = $ Nitrogen Requirement 200 200 200 ? = 1 field losses Please write your responses below. J = 1 field losses T = 1 field losses L = 1 field losses ? = 1 field losses 137 (17a) Please specify the potential yield, M, for variety 1, that would make you indifferent between variety 1 and variety 2 with the characteristics shown below. Characteristics Variety 1 591 egggegfy 2 591 QDQESQ Potential Yield M = ? 100 120 Field Losses 201 201 201 Nitrogen Requirement 200 200 200 M = bulacre potential yield (17b) Please also write your answer for M in the table below. Then specify the potential yield, N, for variety 1, that would make you indifferent between variety 1 and variety 2 with the characteristics shown below. Variety 1 Variety 2 Characteristics 591 chance 591 chance Potential Yield N = ? M = 100 Field Losses 201 201 201 Nitrogen Requirement 200 200 200 N = bulacre potential yield 138 (17c) Please write your answer for M in the table below. Then specify the potential yield, 0, for variety 1, that would make you indifferent between variety 1 and variety 2 with the characteristics shown below. Characteristice Variety l 591 QEEEEEFY 2 591 eeeeee Potential Yield 0 = ? M = __”_,__ 120 Field Losses 201 201 201 Nitrogen Requirement 200 200 200 O = bulacre potential yield (17d) Please write your answers for N and O in the table below. Then specify the potential yield for variety 1 that would make you indifferent between variety 1 and variety 2 with the characteristics shown below. Variety 1 Variety 2 gheracteristics 591 egeeee, 591 eneeee_ Potential Yield ? N = O = _______ Field Losses 201 201 201 Nitrogen Requirement 200 200 200 ? = bulacre potential yield Please write your responses below. M = bulacre potential yield N = bulacre potential yield 0 = bulacre potential yield ? = bulacre potential yield 139 (18a) Please Specify the nitrogen requirement, P, for variety 1, that would make you indifferent between variety 1 and variety 2 with the characteris- tics shown below. Variety 1 Variety 2 Characteristiee 591 eflegee, 591 eneeee Potential Yield 100 100 100 Field Losses 201 201 201 Nitrogen Requirement ? = P 150 200 P = lblacre nitrogen requirement (18b) Please write your answer for P in the table below. Then specify the nitrogen requirement, Q, for variety 1, that would make you indifferent between variety 1 and variety 2 with the characteristics shown below. Variety 1 Variety 2 Characteristics 591 chance 591 chance Potential Yield 100 100 100 Field Losses 201 201 201 Nitrogen Requirement ? = Q P = 150 Q = lblacre nitrogen requirement 140 (18c) Please write your answer for P in the table below. Then specify the nitrogen requirement, R, for variety 1, that would make you indifferent between variety 1 and variety 2 with the characteristics shown below. Variety 1 Variety 2 Characteristics 591 chance 591 ehance Potential Yield 100 100 100 Field Losses 201 201 201 Nitrogen Requirement ? = R P = 200 lblacre nitrogen requirement (18d) Please write your answers for Q and R in the table below. Then specify the nitrogen requirement for variety 1 that would make you indif- ferent between variety 1 and variety 2 with the characteristics shown be] ow. Variety 1 Variety 2 Characteristics 591 EDQEQQ. 591 egeeee Potential Yield 100 100 100 Field Losses 201 201 201 Nitrogen Requirement ? Q = R = lblacre nitrogen requirement Please write your responses below. p = Q = ._______ R: ? lblacre nitrogen requirement lblacre nitrogen requirement lblacre nitrogen requirement “.... ,lb/acre nitrogen requirement 141 An Example to Help in Answering Question 19 (19) Suppose you are considering two varieties. You know, for certain, that variety 1 has the the characteristics shown under variety 1. You also know that variety two has some probability of having the characteristics shown in the first column under variety 2 and some probability of having the characteristics shown in the second column under variety 2. What probabil- ity, p, of variety two having the characteristics in column 1 under variety two and probability (l-p) of variety two having the characteristics in column 2 under variety 2 would make you indifferent between the two varieties? To answer these questions, it may be easier to think of variety 1 as a sure thing, and variety 2 as a gamble between the two columns. Since the prob~ abilities on the two columns must add up to one, the probability for the second column occurring is just one minus the probability of the second column occurring. You do not need to specify the probability for the second co umn. The following example might help to explain how to answer the questions: Let's say I am presented with a choice between two fruit baskets, the contents of which are shown below. Fruit Basket 1 Fruit Basket 2 Characteristics 2 ehance (153) chance Apples 10 10 2 Oranges 5 15 5 Bananas 0 0 0 = .7 would make me indifferent between the two fruit baskets. This says that I am indifferent between receiving 10 apples, 5 oranges and no bananas and playing a gamble in which I have a 7 out of 10 chance of getting 10 apples, 15 oranges and no bananas and a 3 out of 10 chance of getting only 2 apples, 5 oranges and no bananas. 142 Some of your responses from questions 16, 17, and 18 will be needed to answer question 19. Please transfer them from the previous pages to the spaces provided below. 1 field losses L 1 field losses potential yield 0 R potential yield 0 z -i II = nitrogen required = nitrogen required (a) Hhat p would make you indifferent between variety 1 and variety 2 shown below? Variety 1 Variety 2 Characteristics a_ehegee, (1—2) engage Potential Yield 120 120 100 Field Losses 201 01 201 Nitrogen Requirement 200 150 200 p = _______ would make me indifferent between variety 1 and variety 2. (b) Please write your responses for L, N, O, and T in the appropriate spaces below. Then answer the question: what p would make you indifferent between variety 1 and variety 2 shown below? Variety 1 Variety 2 Characteristics 9 chance (172) engage Potential Yield 0 = O = N = _____ Field Losses L = _____ T = L = Nitrogen Requirement 200 200 200 p = would make me indifferent between variety 1 and variety 2. 143 (c) Hhat p would make you indifferent between variety 1 and variety 2 shown below? Variety 1 Variety 2 Characteristics 9 eneeee, (172) eeeeee Potential Yield 100 120 100 Field Losses 201 01 201 Nitrogen Requirement 150 150 200 p = ________would make me indifferent between variety 1 and variety 2. (d) Please write your answers for N, O, Q, and R in the appropriate spaces below. Then answer the question: what p would make you indifferent between variety 1 and variety 2 shown below? Variety 1 Variety 2 Characteristics 2 chance (172) chance Potential Yield N = 0 = N = Field Losses 201 201 201 Nitrogen Requirement Q = Q = R = p = would make me indifferent between variety 1 and variety 2. 144 (e) Hhat p would make you indifferent between variety 1 and variety 2 shown below? Variety 1 Variety 2 gamma; 2 change (1:2) 91111122 Potential Yield 100 120 100 Field Losses 01 01 201 Nitrogen Requirement 200 150 200 p = _______ would make me indifferent between variety 1 and variety 2. (f) Please write your answers for L, R, Q, and T in the appropriate spaces below. Then answer the question: what p would make you indifferent between variety 1 and variety 2 shown below? Variety 1 Variety 2 Characteristics 2 chance (179) chance Potential Yield 100 100 100 Field Losses T = T = __““_ L = Nitrogen Requirement R = Q = R = p = would make me indifferent between variety 1 and variety 2. 145 Thank you very much for participating in this study and completing the questionnaire. You have been a big help to me! If you are curious as to what your responses indicate about your attitudes towards risk, please be sure to write your address on the second page of the instructions. I an- ticipate having the results in about a month and would be happy to send them you. By this time, you are probably tired of answering questions. But I have one last one for you. would you take a moment and briefly tell me what your background in farming is. For example, do your parents farm or do you anticipate farming or working in an agricultural industry when you graduate? In addition, I would like to know if you have been involved in making decisions similar to the ones you answered questions about here. THANKS AGAIN !!! For this decision situation, dried at the elevator. You normally harvest corn at 251 moisture content and want to dry it down to 151 (grade 2). You have made a trip to the farm machinery dealer to discuss dryers, but have not yet decided which one to purchase. automatic batch dryers and some which are continuous flow. The dryers which 146 APPENDIX 58 PURCHASING A CORN DRYER The dealer has told you about several dryers, some which are you are considering vary with respect to: 1. 9519; Ca acit which, for the dryers you are considering, ranges rom 150 to 200 bushels per hour, depending on the dryer selected. gee; of Drying E ui ment which, for the dryers you are considErTfig, ranges rom $10,000 t0 $20,000. Operating Cost which is comprised mainly of the cost of electricity or LP to run the dryer and, for the dryers your are considering, ranges from 9 to 13 cents per bushel. imagine that you own a 40,000 bushel corn operation and have decided to buy a grain dryer rather than have your grain 147 FINANCING A COMBINE For this decision situation, imagine that you have decided to purchase a new combine. The self propelled combine, with headers, is going to cost you $75,000. You have been shopping around for a loan to finance the combine. Several sources are willing to loan you the money, with at least the com- bine as collateral, but the loans differ with regard to: 1. Interest Rate which ranges from 111 to 151 2. Years tg,Eey_Back 59e_Lgee, also known as years to amortize the loan, which range from 7 to 10 years 3. Collateral Reguireg which, in addition to the combine it- self, ranges from none to an additional $20,000 worth of machinery and equipment. CHAPTER 6 SUMMARY, CONCLUSIONS, AND ISSUES REQUIRING FURTHER RESEARCH The research presented in this dissertation was motivated by the ap- parent instability of the ArrowbPratt coefficient of absolute risk aversion across situations. Despite this perceived instability, the Arrow-Pratt coefficient has continued to be one of the major measures used to describe individuals' attitudes towards risk, order individuals according to their attitude towards risk, and generalize their responses to risky events across situations. Recent work by mathematical psychologists suggests the need to separate an individuals attitude towards risk from their strength of preference for riskless outcomes in order to examine the stability of each component across situations and over time. In essence, this approach calls for a re—examination of the behavioral assumptions underlying ex- pected utility theory. In the dissertation, particular attention was given to three behavioral assumptions and the implications of their violation on the stability of the Arrow-Pratt coefficient of absolute risk aversion. The three assumptions are: 1. Individuals have constant marginal value for money. 2. Preferences are homogeneous. 3. Preferences remain invariant between certainty and uncer- tainty, other things being equal. 148 149 In response to evidence of consistent violation of these three assump— tions, a new measure of attitudes towards risk was developed whose assump- tions are believed to more accurately reflect individual's behavior. This chapter briefly summarizes the research conducted, explores in further depth the methodological questions which have arisen, discusses issues requiring further research and examines what can be concluded at this juncture. m: Chapter 2 begins with a brief review of the historical development of utility theory in order to discover the source of the three assumptions listed above. It was found that the assumption of constant marginal value for money stems from the early cardinalists' argument that money could be used as a measuring rod for utility and, as such, must have constant units of value just as each inch on a standard ruler must represent the same unit of measure. The assumption of homogeneity of preferences stems from Jevons and Marshallian demand theory which argues that the last unit of a good purchased by any individual gives him equal value or satisfaction as the monetary equivalent of that unit of good. Since, in a perfectly competitive market at equilibrium, each individual faces identical prices, it is argued that individuals' marginal utility is equal. Thus, all individuals would obtain the same degree of satisfaction of needs from the last unit pur- chased which is, in turn, the same degree of satisfaction they would obtain from having an amount of money equivalent to the price of that good. This assumption ignores the concept of consumer surplus. If an individual's preferences meet the conditions implied by these two assumptions, their indifference curves for any two goods, or any one good 158 and money, are straight lines with a slope of negative one. Indifference curves of this type can be obtained when an individual's value and utility functions over multiattributed outcomes are additive. If both the utility and value functions meet these conditions, the utility function must be a positive linear transformation of the value function. This positive linear transformation mathematically ensures that preferences are invariant under certainty and uncertainty. The implications of violations of the assumptions of constant marginal value for money and homogeneous preferences for our ability to measure and compare attitudes towards risk using the Arrow-Pratt coefficient of ab- solute risk aversion were demonstrated graphically. Specifically, it was shown that, even if an individual actually has stable attitudes towards risk, if his preferences for riskless outcomes do not conform to these assumptions, his risk attitude, measured using the Arrow-Pratt coefficient, will appear unstable. Chapter 3 begins with the conceptualization of a means whereby intrin- sic attitudes towards risk can be determined by separating the effect of attitude towards risk on a von Neumann-Morgenstern utility function from the effect of preferences for riskless outcomes. Recent work on intrinsic risk attitude by Dyer and Sarin (1981) is discussed and illustrated graphi- cally. (Note that what is referred to as intrinsic risk attitude is called relative risk attitude by Dyer and Sarin and others in the mathematical psychology and management science literature. The terminology was modified by this author to avoid confusion with an entirely different concept, the Arrow-Pratt coefficient of relative risk aversion.) It was shown that Dyer and Sarin's local measure of intrinsic risk attitude effectively compen- sates for violations of the assumptions of constant marginal value for 151 money and homogeneous preferences. However, the global measures of intrin- sic risk attitude developed by Dyer and Sarin place severe restrictions on the form which the individual's value function and utility function may take. Their measures require that one of the following two conditions hold: 1. All problems are simple value problems, i.e., that outcomes refer to only one attribute, or 2. Preferences for attributes in multiattributed outcomes are independent and additive. The first condition does not allow for cases where, for example, a farmer is concerned with not only profits, but also his asset/debt ratio, quality of life, soil productivity, or implications of current decision outcomes for future flexibility in the organization of the farm firm. The second condition allows for consideration of several attributes, but requires that value of attainment of any level of one attribute is completely independent of the initial levels or changes in the levels of other attributes. In other words, the individual's multiattribute value function must be addi- tive. In Chapter 4, a new measure of attitude towards risk was developed which builds upon the work done by Dyer and Sarin. It begins with a closer examination of the independence conditions which preferences for attributes in a multiattributed outcome must meet in order to assume their additive or multiplicative combination. The new method of separating attitudes towards risk from preferences for riskless outcomes is more general than previously developed methods because it allows for consideration of a larger class of value functions. Specifically, while previous work requires that preferences meet strong independence conditions required for additive combination of preferences for different attributes of an outcome, the new theory only requires that preferences meet the weaker conditions of 152 independence required for their multiplicative combination. The need for this generalization was confirmed by the finding that fifty out of fifty- nine respondents to a questionnaire administered by the researcher had preferences which met the conditions for multiplicativity while only nine respondents had preferences which also met the stricter conditions for additivity. The new measure of intrinsic attitude towards risk was developed using Cauchy's four fundamental functional equations to ascertain the transforma- tions between additive or multiplicative multiattribute value and utility functions. These transformations are then to determine intrinsic attitudes towards risk. These transformations allow one to do three things: 1. Given a utility function, u(x), and a value function, v(x), determine u(v), the utility for the riskiness of outcomes. 2. If u(v) is stable across situations, determine v(x) from u(x) or vice versa. 3. In modeling behavior, separate the influence of strength of prizerence for riskless outcomes from attitudes towards Use of the new measure is illustrated with hypothetical additive and multiplicative value and utility functions. It is shown that, while Dyer and Sarin‘s local measure of intrinsic attitude towards risk holds when the value function is either additive or multiplicative, the new, more general measure which allows for multiplicative value functions is needed for a global measure of intrinsic risk attitude. The procedures used to collect data to examine the empirical validity of the new measure and the and the stability of intrinsic attitude towards risk across situations are discussed in the beginning of Chapter 5. This includes a description of the basic methods used in multiattribute utility theory as well as discussion of some of the current debate over certain 153 aspects of these methods. The questionnaire used in this study is then described and discussed. ’ Attempts to use the data collected with the described instrument to examine the theory were beset by difficulties; the data could not be used to clearly support or refute the new measure's predictive power because of mathematical inconsistencies in the responses. The question which remains to be answered is whether these (lnconsistencies reflect 'fuzzyness' in human cognition which prevents individual's from accurately educing their preferences or whether these inconsistencies reflect the fact that in- dividuals preferences do not conform to the behavioral assumptions underly- ing the methods used. This issue is discussed in the sections below. Eleeleg,§9e_Research 19 Qgeeege This research has been primarily concerned with re-examining a subset of the behavioral assumptions of expected utility theory and their implica- tions for measures of attitudes towards risk such as the Arrow-Pratt coef- ficient of absolute risk aversion. The reader will recall that the expected utility hypothesis assumes, among other things, invariance of preferences between certainty and uncertainty when other things are equal, homogeneity of preferences and constant marginal value of money. It has been argued that because these behavioral assumptions diverge from actual preferences, the Arrow-Pratt coefficient of absolute risk aversion does not reflect a decision makers' true attitude towards risk. Therefore, our methods of determining attitudes towards risk must be modified to more accurately reflect decision makers' behavior. The test of a hypothesis is usually preceded by the formalization of an if, then statement such as, if the global measure of intrinsic risk 154 attitude accurately reflects decision maker's preferences, then a utility function indirectly obtained using the individual's multiattribute value function and the appropriate transformation described by (4A.1), (48.1), (4C.1) or (40.1) will be a positive linear transformation of the individual's directly elicited von Neumann-Morgenstern utility function. In a discussion of the basic elements of a good test of a hypothesis, Giere (1979, pp. 86-94) argues that this simple if, then statement is not sufficient; one needs to specify not only the hypothesis, H, and the prediction, P, but also the initial conditions, IC, and auxiliary assump- tions, AA, which are expected to hold, such that the following two condi- tions are true. Condition 1: If [H and IC and AA], then P Condition 2: If [not H and IC and AA], then very probably, not P Note that the if statement contains not only the hypothesis, but also the initial conditions and auxiliary assumptions. It must be remembered that only a few behavioral assumptions of the axioms of expected utility theory were examined: the remaining content of the theory was assumed to reflect accurately decision maker behavior. (For summaries of recent research done on the behavioral and mathematical con- tent of the independence and other axioms of expected utility theory, the reader is referred to Schoemaker (1982) and Machina (1983).) This strong assumption created somewhat of a methodological paradox in the collection and analysis of data in a study designed to test the new measure of at- titudes towards risk: while the behavioral content of expected utility theory was being examined, the representation theorem underlying expected utility theory, including the independence axiom, was needed to collect the 155 data. Several aspects of these assumptions are relevant in light of the inconsistencies pervading the collected data. More formally stated, the initial conditions used in the study dis— cussed in Chapter 5 were that all of the assumptions underlying the axioms of expected utility theory and multiattribute utility theory except the assumptions of constant marginal value of money, homogeneity of preferences and invariance of preferences between certainty and uncertainty are mathe- matically correct and accurately reflect decision maker behavior. The auxiliary assumptions employed relate to the methods used for measurement and include the assumptions that individuals can accurately educe their preferences and that individuals can understand and effectively work with probability concepts. Assuming, for the purpose of argument, that the inability to complete the analysis implies an incorrect prediction, we might reason through a test of the hypothesis using the following logic: First Premise: If [H and IC and AA], then P Second Premise: Not P Preliminary Conclusion: Not [H and IC and AA] Preliminary Conclusion: Not H or not IC or not AA At this point, we must make explicit our commitments to the truth of both the initial conditions and auxiliary assumptions. The emphasis above on the fact that only a few of the assumptions underlying the expected utility hypothesis were examined has alluded to the lack of commitment to the truth of the remaining assumptions. The remainder of this section and the ones following bring to light more issues which prevent us from con- tinuing with the deduction that: 156 Additional Premise: IC and AA (are true) Conclusion: Not H Instead, we are left with the second preliminary conclusion: Preliminary Conclusion: Not H or not IC or not AA Most axiomatizations in measurement theory try to capture an important property of real numbers called the Archimedian property. Roberts (1979, p. 123) defines this property as follows: ”If a and b are real numbers and a > 0, then there is a positive integer n such that na > b. That is, no matter how small a might be or how large b might be, if a is positive, then sufficiently many copies of a will turn out to be larger than b.” This property of the real number system is what makes measurement of any type, including utility, possible by making it possible to roughly compare the relative magnitudes of any two quantities by seeing how many copies of the first quantity are needed to exceed the second, larger quantity. This condition is necessary to achieve a homomorphic mapping from an abstract relational system, such as preferences, to the real line, yielding a utility function. The Archimedian property is embodied in the continuity axiom of expected utility theory which states that if an individual prefers A to B to C, then there exists an unique probability, p, such that he will be indifferent between B and a lottery of the form pA + (1-p)C. Note that this is the exact form of the questions used in the questionnaire to elicit information needed to determine the scaling factors for multiattribute utility functions. It may be argued that the Archimedian axiom requires standards of accuracy which are unrealistic. For the interpolations involved in decision analysis to be valid, decision makers must not only have a good 157 understanding of probability, but their responses must also be accurate and precise. However, the decision makers responses may often vary because of the inability to accurately educe preferences, changes in preferences over time, changes due to introspection about preferences evoked by closer examination, or in response to feedback about mathematical inconsistencies which may cause the decision maker to alter responses to the extent that they may or may not reflect true preferences. Another set of assumptions which come into play in extending expected utility theory to multiattribute utility and value theory are mutual preference and mutual utility independence. These conditions require that the weight that the individual gives to each attribute will not vary with changes in the levels of other attributes. Mutual independence only holds if the weight given to one attribute when other attributes are at a specified level does not change when the attributes are at another level. Evidence of failure of preferences to meet this condition can be found if the individual has weights which are not constant. Hhile generalized preference and utility independence allow for symmetric reversals in preferences to occur when moving from the domain of gains to the domain of losses, or vice versa, generalized independence does not allow for asym- metrical reversals in preferences. Violation of generalized independence can easily occur if the individual attaches a different weight to improving the level of an attribute than he does to maintaining or preventing a decrease in the level of the attribute. In the questionnaire, generalized independence was only checked over one domain (either gains or losses) rather than over both. Therefore, the apparent satisfaction of the condi- tions of generalized independence may be misleading. 158 Kahneman and Tversky (1979) describe this reversal of preferences about the status quo as the reflection effect and argue that preferences in the domain of losses are a mirror image of (symmetric with) preferences in the domain of gains. However, Friedman and Savage (1948) argue that preferences in the domain of losses are not symmetric with those in the domain of gains. Instead, they argue that the utility function in the domain of losses is much “steeper" than that in the domain of gains. They support this argument with the observation that individuals will, given the chance at significant gains, participate in unfair odds and, for the prevention of much smaller losses, accept equally unfair odds to preserve the resources which they hold. Although there is much disagreement with the specifics of the 'everymans‘ utility function“ Friedman and Savage developed in response to this observation, the observation has been reconfirmed by subsequent studies. It is important to remember that the axioms of utility theory not only define ”rational behavior“ but go much further and define behavior which must be described both precisely and with mathematical consistency. This presents a dilemma to both the decision analyst and the decision maker: if the decision makers' preferences meet the conditions set forth in the axioms, the theory may be interpreted as a good descriptor of behavior and used to predict behavior while if the decision makers' preferences do not meet conditions set forth, the theory becomes prescriptive. In the latter case, the decision analyst may appeal to the apparent reasonableness of the axioms and the rationality of the decision maker in asking him to revise his responses. But a decision maker can be reasonable and have sound reasons for particular preference structures without conceding to the axioms: in this case, the decision analyst must reflect on how far they can 159 push for mathematical consistency and still accurately reflect the preferences of the decision makers. Efstanthiou (1984, p. 310), in a dis- cussion of this issue, argues that: "..in obtaining utility curves for single attributes and imposing the ax oms of multiattribute utility theory, a dangerous mixture of descriptive and normative procedures will be produced. " Ieegee_8egglgigg Further Reseegen The myriad issues which require further research can be classified into three major areas: mathematical content of the axioms, behavioral content of the axioms and the educement of preferences. The third area, although formally a subset of the behavioral content of the axioms, has enormous impact on the issue of mathematical consistency. Currently, research is being done in all three areas by researchers from many different dis- ciplines. Three particularly promising areas of research directly related to the problems discussed above are described briefly below. The issue of 'fuzzyness' in human cognition has plagued decision analysis since its inception. In contrast to the uncertainty due to random- ness of events external to the decision maker, this fuzzyness results from a form of uncertainty due to vagueness and imprecision internal to the decision maker. According to the proponents of fuzzy set theory, these distinct qualities must be modeled in different ways, the former using probability theory and the latter using fuzzy set theory. Fuzzy set theory provides a means of quantifying the degree of imprecision associated with any input into the decision process through the use of membership func- tions. Hatson, Heiss and Donnell (1979) argue that probabilities and utilities can inherently only be represented by somewhat rough sets of 160 numbers. Their “fuzzy decision analysis“ method is motivated by the need to handle the imprecision accompanying the judgemental inputs into decision analysis in a systematic and consistent manner. Zadeh (1965), one of the first to argue for a new fuzzy approach to systems analysis and decision making under uncertainty, holds that fuzzy set theory is not an alternative to probability theory and expected utility theory but is, instead, a parallel calculus to be used to handle the im- precision inherent in human cognitive processes. The central concept in fuzzy set theory is the membership function which numerically represents the degree to which an element belongs to a set. The function is valued between zero and one and is assessed subjectively with small values repre- senting a low degree of membership in the set and high values representing a high degree of membership. For example, the statement “it will probably rain tomorrow“ would have a higher degree of membership in a set regarding likelihood of rain than the statement ”it might rain tomorrow". In applica- tions of fuzzy set theory, the values used to represent degrees of member- ship are not elicited directly. Instead, they are taken from curves drawn by individuals to represent their degrees of belief that an event will occur. The calculus of fuzzy sets is based on three propositions to which numbers indicating membership should conform. These propositions are analogous to those used in conventional set theory and include: 1. The degree to which X belongs to set A and set 8 is equal to the smaller of the individual degrees of membership. 2. The degree to which X belongs to either set A or set 8 is equal to the larger of the individual degrees of membership. 3. The degree to which X belongs to (not A) is one minus the degree to which X belongs to A. 161 The calculations involved in the decision analysis can be considered to be a functional relationship between the inputs regarding probabilities and utilities and the output of the analysis in the form of the expected utility of an action choice. The three relationships cited above are used to deduce the 'fuzz' on the output given the fuzzyness of the inputs.1 As with conventional utility analysis, probability distributions may be gener- ated which characterize the range of possible outcomes for each action choice. Hhereas the distributions obtained from conventional analysis are taken to be the true distributions, in fuzzy set theory the extent to which the distribution of inputs, probabilities and utilities implies a preferred action choice is only as large as the least level of implication for each set. Unless one distribution clearly dominates another, it cannot be said to indicate the preferred action choice. To determine the preferred action choice when two sets overlap, one must determine the extent to which one set is preferred over the other through the use of Zadeh's fuzzy calculus. There remain questions regarding the axiomatization of a fuzzy set calculus which can be used to elicit membership functions. Experimental evidence does show, however, that individuals are able to draw curves or probability distributions to represent their perceived imprecision regard~ ing degrees of belief such as "better than ever”, “pretty likely", or ”about X1". The precise shapes of these distributions are somewhat ar- bitrary, but this fact does not affect the inferences which can be drawn from fuzzy set analysis as it is the general shape of the distributions that matter. 1 For particulars of the mathematical methods used, see Hatson, Weiss and Donnell (1979) and Zimmermann, Zadeh and Gaines (1984). 162 Machina (1982), in examining the mathematical content of the independ- ence axiom of expected utility theory starts with the observation from elementary calculus that for a function to be differentiable, it must be locally linearly approximable. The independence axiom is like a linearity assumption for utility functions; it implies that the utility function may be represented as the expectation with respect to the given distribution of a fixed function defined over the set of possible outcomes. In other words, the utility function is constrained to be a linear function over the set of distributions of outcomes or, as commonly phrased, "linear in the probabilities”. However, empirically determined utility functions do not always conform to the linearity condition because of the certainty effect or other phenomena. Machina argues that, despite these violations, the basic concepts, tools and results of expected utility analysis are still applicable because they are not dependent upon the independence axiom. They can also be derived from a weaker assumption of local smoothness of preferences over alternative probability distributions. Machina shows that if you can assume that preference orderings underlying the utility function in a region are a differentiable functional, then the utility function is locally linear. Hence, the utility function is differentiable and the results of expected utility theory hold, at least locally since, at each point, a locally linear utility function can be obtained. Hith his generalized utility analysis, Machina elegantly proves that the assumption of smoothness of preferences and consistency in the shape of the utility function in a given region, in essence, rescues the independence axiom. Machina does not prove the local applicability of the other axioms of expected utility theory. 163 Hhile Machina examines the mathematical content of the independence axiom, Heiss (1983, 1984), with equal mathematical rigor, examines the behavioral content of the axioms. Neiss begins with the observation that lotteries, which can be expressed as cumulative distribution functions, can take several forms including degenerate lotteries, where the probability of the outcome occurring is one, and continuous lotteries, where the probabil- ities of outcomes sums to one. Degenerate lotteries coincide with the case of certainty while continuous lotteries coincide with the case of uncer- tainty. In Heiss' approach, decision makers compare lotteries according to their measurable utility and are allowed to use a “two-rule“ measurable utility function which allows, but does not require, them to use one preference rule for choosing between degenerate lotteries and another for choosing between continuous lotteries. In a model of producer response to price uncertainty, Heiss finds that, when a decision maker is allowed to use a “two-rule“ measurable utility function, he generally will choose a utility maximizing output level different from the one he would choose if he followed a more restrictive expected utility maximizing approach. In particular, if his marginal utility of money is greater under certainty than under uncertainty and both the expected utility and measurable utility models have interior solutions, then the latter model will generate a lower optimal production level than the former. Furthermore, it will prove pos- sible to have a zero production level and a positive production level being simultaneously optimal (Weiss, 1983, p. 16). A particular pricing situation to which his analysis applies is that of random price that is truncated below the mean through the introduction of a support price. 164 These three examples illustrate the breadth of possibilities which can be explored by researchers in decision theory, all of which are useful in moving towards resolution of the common problems encountered in this dis- sertation. The first priority of this researcher is to obtain the mathe- matically consistent responses required to complete a test of the new measure of attitudes towards risk. This will 'require careful, lengthy procedures to elicit the multiattribute value and utility functions for actual decisions faced by a small group of decision makers. Particular attention needs to be paid to the issue of how far responses can be altered to meet the consistency required for analysis and still reflect decision makers' preferences. In the longer run, Neiss' suggestion (personal com- munication) that localized behavioral theorems based on preference order- ings, analogous to the work done by Machina on the mathematical content of the axioms of expected utility theory, be developed seems promising and in keeping with the concerns which originally motivated this dissertation research. There is strong evidence to refute many of the behavioral assumptions underlying the axioms of expected utility theory. It has been demonstrated that if decision makers' preferences violate any ohne of the assumptions of constant marginal utility of money, homogeneity, or invariance of preferences between certainty and uncertainty when other things are equal, the Arrow-Pratt coefficient of absolute risk aversion is a confounding of information about attitude towards risk and preferences for the attributes of outcomes under certainty. Conformance of decision makers' preferences 165 with each of the three assumptions is necessary, but not sufficient, for the Arrow-Pratt coefficient to measure only attitude towards risk. It has been shown that, when any one of these assumptions is violated, measurement of attitude towards risk requires consideration of the individual's value function as well as his von Neumann-Morgenstern utility function. Dyer and Sarin's measure of intrinsic risk attitude (known in the mathematical psychology and management science literature as relative risk attitude) introduces a useful approach to this problem. However, it was demonstrated that their method unduely constrains analysis to those cases where individuals' preferences for the attributes of outcomes under cer- tainty are completely independent and additive. A new measure of attitude towards risk that is more general than Dyer and Sarin's measure has been developed. This new measure is applicable to individuals whose preferences for attributes of outcomes under certainty or uncertainty are either additive or multiplicative. It was found that determining individual's multiattribute value and utility functions without forcing mathematical consistency results in data that does not meet the level of consistency required to determine scaling factors for either the additive or multiplicative multiattribute models. At this Juncture, it can not be determined whether the inconsistencies in responses to the survey instrument are due to problems with the new measure of intrinsic risk attitude, fuzzyness in human cognition, mis-specification of initial conditions and auxiliary assumptions, or poor design of the survey instrument. The issue of mathematical consistency is particularly important for this new measure of attitudes towards risk. Hhile many of the studies of multiattribute utility or value theory are concerned with either an 166 individual's value function or their utility function, the new measure of attitudes towards risk is concerned with the relationship between the individual's value and utility functions. Therefore, both functions must be measured accurately and shown to reflect decision makers’ preferences before the new measure of intrinsic attitude towards risk can be tested. Resolution of this question requires that other assumptions of expected utility theory and multiattribute utility theory undergo scrutiny similar to that received by the assumptions examined in this dissertation. 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