The Power of Exclusion using Automated Osteometric Sorting: Pair‐Matching,

Abstract

This study compares the original pair-matching osteometric sorting model (J Forensic Sci 2003;48:717) against two new models providing validation and performance testing across three samples. The samples include the Forensic Data Bank, USS Oklahoma, and the osteometric sorting reference used within the Defense POW/MIA Accounting Agency. A computer science solution to generating dynamic statistical models across a commingled assemblage is presented. The issue of normality is investigated showing the relative robustness against non-normality and a data transformation to control for normality. A case study is provided showing the relative exclusion power of all three models from an active commingled case within the Defense POW/MIA Accounting Agency. In total, 14,357,220 osteometric t-tests were conducted. The results indicate that osteometric sorting performs as expected despite reference samples deviating from normality. The two new models outperform the original, and one of those is recommended to supersede the original for future osteometric sorting work.

An Automated Two‐Dimensional Form Registration Method for Osteological Pair‐Matching

“…However, this procedure should not be applied to open populations as the results will vary due to the increased amount of variation. In such a situation, the distances calculated may need to be evaluated through statistical tests, such as calculating t‐ statistics to provide shortlists of nonexclusions following previous pair‐matching methods .…”

“…This is an important point to understand as there is no statistical guarantee the potential match is correct. The identification of whether or not a true‐pair exists ultimately comes down to forensic expertise through visual pair‐matching, which has been advocated in previous pair‐matching literature .…”

“…Traditional osteological pair‐matching methods rely on linear measurements to account for differences between paired elements . These methods have been shown to achieve high accuracy and exclusion rates .…”

Amelia Earhart and the Nikumaroro Bones: A 1941 Analysis versus Modern Quantitative Techniques

“…Sassouni (1960) achieved 100 percent matching of premortem cranial radiographs to postmortem candidates using eight cranial measurements. In an analogous situation, pair matching has proved effective in reassociating commingled remains (Lynch et al 2017). The fit of the Nikumaroro bones to Amelia Earhart was assessed using Mahalanobis distance (D) and considered in relation to all other individuals in the database.…”

Univariate and Linear Composite Asymmetry Statistics for the “Pair‐Matching” of Bone Antimeres

“…The “absolute value of sum difference” suggested by Vickers and co‐workers (:103) can then be shown to follow a folded exponential power distribution. For the “summed absolute value of differences” as described by Lynch and co‐workers (:2), it was necessary to fit a skew exponential power distribution . Rather than only assessing a single quantile, which in Vickers et al's case was at the 0.10 probability value, this paper uses complete quantile‐quantile plots to check the fit of the composite score to theoretical distributions.…”