Assessing the Accuracy of Decomposition Scoring Methods in Arizona’s Sonoran Desert

As the humanitarian crisis at the U.S.–Mexico border continues to worsen, there is a growing need to identify migrants who die in attempts to cross. Part of the identification process includes establishing the postmortem interval (PMI): how much time passed between the individuals’ deaths and when their remains were found. This thesis assessed the accuracy of three PMI assessment methods using four pig models in the Sonoran Desert at Arizona’s border with Mexico during the summer. The scoring method as outlined by Megyesi and colleagues (2005), the pig-specific method by Keough and colleagues (2017), and the currently-developing Geographic Information Systems (GIS) method by Kenyhercz and colleagues (2015) were applied twice daily to all pigs. Two of the pigs were clothed to approximate the conditions in which migrant remains are found and to test whether clothing status affects the scoring methods’ performance. The data were analyzed through a series of linear regressions and a repeated measures analysis of variance (ANOVA). The results of this study suggest that only the GIS method accurately estimates the PMI in this environment, while the other two methods tend to drastically overestimate the PMI. Clothing status did not significantly affect the performance of any scoring method.