Human Decomposition and Time Since Death: Persistent Challenges and Future Directions of Postmortem Interval Estimation in Forensic Anthropology.

Estimating the time since death, or the postmortem interval (PMI), is a significant component of forensic anthropological analysis when human remains are discovered. Despite decades of research, methods for providing an estimate of the PMI with known error rates are still absent from applied medicolegal forensic work, which prompts the necessity for a critical examination of the state of the field. This review details the history of how forensic anthropology emerged from the broader discipline of biological anthropology, with a specific focus on how forensic anthropologists came to be understood as suitable experts for estimating the PMI. We describe existing PMI estimation methods and enduring barriers in advancing our knowledge. We provide an overview of the formative PMI research, then focus on a systematic review of 30 years (1993-2023) of human decomposition literature. Results of our synthesis demonstrate the two prevailing ways to estimate the PMI involve (1) the use of quantitative biomarkers and (2) macromorphoscopic observations. Results also highlight that PMI research continues to be limited by small, highly variable samples and a lack of standardized definitions of decomposition, which impedes replicability and the advancement of methods for PMI estimation. Forensic anthropologists can address these longstanding issues by ensuring the principles of Open Science are adhered to during the research and dissemination process including data sharing and transparency. Intentional research design that integrates comprehensive geospatial data and improved modeling techniques can contribute to devising methods capable of providing PMI estimates within applied medicolegal and humanitarian contexts.