ABSTRACTASSESSING THE EFFECT OF VARIED DESIGN ELEMENTS ON INFORMATION PROCESSING IN MEDICAL DEVICE LABELS By Do Chan SeoThe labeling of medical devices plays a very important role in communicating product information to healthcare providers so that the device is used safely and effectively. Cai (2012) identified various labeling issues as problematic in medical devices. Specifically: small font sizes, poor color contrasts, absence of latex status or sterility status, and varied locations for three pieces of critical information (latex status, sterility status and expiration dating). Research proposed herein is comprised of three experimental parts: (1) a benchmarking study to verify (or refute) Cai's findings, (2) a study investigating how design strategies impact early stages of information processing using a change detection methodology; this portion also evaluates symbol comprehension, and (3) a forced choice task which enumerates the effect of design elements on the correct selection of a device and time to select the same. The four design factors which were evaluated are: grouping of critical information, boxing of critical information, symbol presence/absence and color coding.The key findings from our benchmarking study support Cai's conclusion (2012) that the three pieces of critical information were scattered throughout medical device labels, and that their font sizes were relatively smaller than those of the product name. Legibility testing also bolstered Cai's findings: all three pieces of information deemed critical to the safe and effective use of a medical device were indicated to be significantly less legible (á=0.05) than product name and brand name when 20 commercial labels were tested by 99 participants. Attentive behaviors of participants were evaluated measuring the proportion of the sample that successfully detected changes to stimulus prior to time out (60 seconds) and time to successful change detection. Participants detected changes significantly faster when the three pieces of critical information were boxed than when they were unboxed, in both grouped (p=0.0086) and ungrouped (p<0.0001) formats. Color-coded designs enabled participants to detect changes significantly faster than non-color-coded design, in both grouped (p<0.0001) and ungrouped (p<0.0001) formats. In addition, the 3-way interaction term of Boxing x Symbol x Color was found to be significant (p=0.0323). Though grouping enhanced performance in treatments with colors, it slowed performance in the boxed conditions.When comprehension rates of symbols were evaluated, only 6 out of 38 symbols in the internationally recognized standard, AAMI/ANSI/ISO 15223: 2007 A1: 2008, were classified as successful. Three symbols from the same standard were categorized as "critically confusing" for participants: they were not only misunderstood, but, in fact, interpreted to have the opposite meaning of what was intended. When subjects were asked to identify a product with a particular feature (e.g. containing latex) as quickly as possible, three design effects, namely, Color (p<0.0001), Grouping (p=0.0104), and Symbol (p<0.0001) decreased time to selection. Grouping information in one location, the presence of symbols and color coding showed significantly higher probability rates and less time to correct device selection when compared with the two commercial labels (á=0.05). Our work indicates that medical device manufacturers should seriously consider employing these design elements to develop a standard labeling format for critical information. Further, policy changes regarding stand-alone graphical representation on medical device labels should be carefully considered prior to their implementation.
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