Bias research in forensic anthropology has focused primarily on the effects of cognitive bias on laboratory analyses. However, bias not only arises from contextual information at the scene, but can also occur during research endeavors, from design and data collection to analysis and interpretation. To date few studies have focused on potential sources of bias in documented skeletal collections, despite their pivotal role in the production of analytical methods in the United States. Therefore, the purpose of this research is to identify potential sources of sample and selection bias in forensic anthropological research using documented skeletal collections. The three goals of this project address different aspects of sample and selection bias that may be potentially encountered during research development, each addressed in a separate manuscript. The first manuscript uses both demographic and craniometric data from eight United States-based documented skeletal collections to investigate whether specific procurement strategies result in collection specific sample bias. Significant differences between collections were identified in both demographic and craniometric data, indicating the presence of collection-specific sample bias. However, collection-specific sample bias does not obscure patterns of normal human skeletal variation, including sex and population. Therefore, documented skeletal collections remain valid sources of sample data. The second manuscript investigates whether collection samples are representative of the population of interest in forensic anthropology by comparing craniometric data from eight documented skeletal collection to the craniometric data found in Fordisc 3.1.322. Collections were most representative of case populations well-reflected in their samples, such as European Americans who comprise the majority in every documented skeletal collection. Furthermore, inherent sample bias was identified in Fordisc, as nearly one quarter of individuals originate from the same data source; inclusion of those data largely impact model performance. Forensic anthropologists are encouraged to continue case submission to the Forensic Anthropology Data Bank to increase the diversity in Fordisc sample sources, bolster reference sample sizes, and increase the number and variety of the demographic populations represented. The third manuscript uses geostatistical and spatial analyses to investigate whether the physical layout, storage of individuals, and curator involvement at documented human skeletal collections introduce selection bias. Sampling frequency was analyzed using spatial variables, demographic information of individuals within each collection, and interview data, which addressed curator involvement. Selection bias was identified and is mainly attributable to the physical layouts of each collection, including cabinet location and shelf height. However, researcher practices—such as evaluating individuals in chronological order—also contribute to uneven sampling distributions. Researchers need to employ sampling strategies to specifically mitigate the effects of collection layout. Valid methods are required for expert court testimony and all attempts to mitigate bias are essential to upholding ethical standards in the criminal justice system. This dissertation demonstrates sample and selection biases exist within documented skeletal collections, but these collections remain invaluable resources for research in forensic anthropology. Additionally, this dissertation provides a foundation for future investigations into biases for the many documented skeletal collections not included in this dissertation
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