This study evaluates the reliability of osteometric data commonly used in forensic case analyses, with specific reference to the measurements in Data Collection Procedures 2.0 (DCP 2.0). Four observers took a set of 99 measurements four times on a sample of 50 skeletons (each measurement was taken 200 times by each observer). Two-way mixed ANOVAs and repeated measures ANOVAs with pairwise comparisons were used to examine interobserver (between-subjects) and intraobserver (within-subjects) variability. Relative technical error of measurement (TEM) was calculated for measurements with significant ANOVA results to examine the error among a single observer repeating a measurement multiple times (e.g. repeatability or intraobserver error), as well as the variability between multiple observers (interobserver error). Two general trends emerged from these analyses: (1) maximum lengths and breadths have the lowest error across the board (TEM<0.5), and (2) maximum and minimum diameters at midshaft are more reliable than their positionally-dependent counterparts (i.e. sagittal, vertical, transverse, dorso-volar). Therefore, maxima and minima are specified for all midshaft measurements in DCP 2.0. Twenty-two measurements were flagged for excessive variability (either interobserver, intraobserver, or both); 15 of these measurements were part of the standard set of measurements in Data Collection Procedures for Forensic Skeletal Material, 3rd edition. Each measurement was examined carefully to determine the likely source of the error (e.g. data input, instrumentation, observer's method, or measurement definition). For several measurements (e.g. anterior sacral breadth, distal epiphyseal breadth of the tibia) only one observer differed significantly from the remaining observers, indicating a likely problem with the measurement definition as interpreted by that observer; these definitions were clarified in DCP 2.0 to eliminate this confusion. Other measurements were taken from landmarks that are difficult to locate consistently (e.g. pubis length, ischium length); these measurements were omitted from DCP 2.0. This manual is available for free download online (https://fac.utk.edu/wp-content/uploads/2016/03/DCP20_webversion.pdf), along with an accompanying instructional video (https://www.youtube.com/watch?v=BtkLFl3vim4).

Background: Accurate estimation of the pre-colonization interval (pre-CI), defined as the period between body deposition and initial insect oviposition, remains a challenge in postmortem interval estimation in forensic entomology. This study quantified the effects of environmental and contextual variables on blowfly oviposition timing using human cadavers. Methods: Daily photographic records from 203 donated cadavers placed at the University of Tennessee Anthropology Research Facility (March 2011–July 2014) were used to document the first observed oviposition of blowflies. Multivariable general linear models evaluated the effects of monthly temperature, black plastic coverage, and pre-placement soft tissue damage on calendar days to oviposition (IO_day) and accumulated degree days (IO_ADD). Results: Temperature was the dominant predictor, explaining substantial variation in pre-CI. Black plastic coverage significantly delayed oviposition and exhibited a temperature-dependent effect. Although soft tissue damage was associated with earlier oviposition in univariable analyses, it did not remain significant in multivariable models. Cold conditions were associated with prolonged and highly variable pre-CI. Conclusions: These findings demonstrate that temperature was the strongest predictor in this observational dataset, while contextual factors such as physical barriers modify colonization patterns. Together, they highlight the need to incorporate environmental and contextual variables into PMI estimation models and support more defensible interpretations of entomological evidence, particularly in cases involving delayed colonization or restricted insect access.