title: An Improved Equation for TBS and ADD: Establishing a Reliable Postmortem Interval Framework for Casework and Experimental Studies.
abstract: Megyesi et al.'s (J Forensic Sci, 2005, 50, 618) paper was important to forensic anthropology as it introduced a quantitative framework for estimating time since death in human cadavers, based upon physical appearance by way of scoring on a novel scale. However, errors concerning rounding, temperature scale, and incorrect use of a statistical regression model render their predictive formula unusable. Based upon only their more reliable data, a more appropriate regression model to predict accumulated degree days (ADD) from total body score (TBS) is presented. The new model is also a superior fit (r(2)  = 0.91) and produces markedly narrower confidence intervals than the original, which also allowed impossible, negative ADD values. Explanations of the shortcomings in the original analysis and calculations are presented, which it is hoped will help forensic scientists avoid making similar mistakes.
authors: School of Forensic and Applied Sciences, University of Central Lancashire, Preston, PR1 2HE, UK.|Department of Natural Science and Public Health, Zayed University, Dubai, Box 19282, UAE.
authors: Colin
authors: C
authors: Moffatt
authors: Department of Forensic Science, Virginia Commonwealth University, Richmond, VA, 23284, USA.
authors: Tal
authors: T
authors: Simmons
authors: School of Forensic and Applied Sciences, University of Central Lancashire, Preston, PR1 2HE, UK.
authors: Jeanne
authors: J
authors: Lynch-Aird
mesh_terms: D001344:Autopsy; D018732:Forensic Anthropology; D049429:Forensic Pathology; D006801:Humans; D011180:Postmortem Changes; D013696:Temperature
keywords: accumulated degree days; decomposition; forensic science; forensic taphonomy; inverse prediction; regression models; statistical models