How should forensic anthropologists correct national weather service temperature data for use in estimating the postmortem interval?

J Forensic Sci. 2015 May;60(3):581-7. doi: 10.1111/1556-4029.12724. Epub 2015 Feb 10.

Abstract

This study examines the correlation between site-specific and retrospectively collected temperature data from the National Weather Service (NWS) over an extended time period. Using iButtonLink thermochrons (model DS1921G), hourly temperature readings were collected at 15 sites (1 validation; 14 experimental) from December 2010 to January 2012. Comparison between the site-specific temperature data and data retrieved from an official reporter of NWS temperature data shows statistically significant differences between the two in 71.4% (10/14) of cases. The difference ranged between 0.04 and 2.81°C. Examination of both regression and simple adjustment of the mean difference over extended periods (1, 2, 3, 4, 5, 6, & 9 months) suggests that on the timescale typical in forensic anthropology cases neither method of correction is consistent or reliable and that forensic anthropologists would be better suited using uncorrected NWS temperature data when the postmortem interval is extended.

Keywords: F6 data; data validation; decomposition rate; forensic anthropology; forensic science; regression analysis; taphonomy.