Accuracy Rates of Sex Estimation by Forensic Anthropologists through Comparison with DNA Typing Results in Forensic Casework

Abstract

A common task in forensic anthropology involves the estimation of the biological sex of a decedent by exploiting the sexual dimorphism between males and females. Estimation methods are often based on analysis of skeletal collections of known sex and most include a research-based accuracy rate. However, the accuracy rates of sex estimation methods in actual forensic casework have rarely been studied. This article uses sex determinations based on DNA results from 360 forensic cases to develop accuracy rates for sex estimations conducted by forensic anthropologists. The overall rate of correct sex estimation from these cases is 94.7% with increasing accuracy rates as more skeletal material is available for analysis and as the education level and certification of the examiner increases. Nine of 19 incorrect assessments resulted from cases in which one skeletal element was available, suggesting that the use of an "undetermined" result may be more appropriate for these cases.

Accuracy Rates of Ancestry Estimation by Forensic Anthropologists Using Identified Forensic Cases

“…Previous research by these authors examined the accuracy of sex estimation from skeletal remains in real‐world forensic cases. In a similar effort, to address the paucity of examinations of the accuracy of ancestry estimation rates in confirmed operational forensic casework, this research uses cases of identified remains to specifically (i) determine the empirical accuracy rate of anthropological ancestry assessment for a sample of contemporary forensic casework with identified‐person ancestry and (ii) investigate any differences in empirical accuracy rates based on practitioner education and certification level, demographic cohort, and date of analysis.…”

Forensic anthropology casework performance: Assessing accuracy and trends for biological profile estimates on a comprehensive sample of identified decedent cases

“…Third, depending on the practitioner's context, they may not be aware that identification of their cases has occurred, as this can require agencies to follow up with the practitioner. Because of these limitations, only recently have samples for assessing field-wide accuracy rates begun to accumulate, with various levels of completeness and accessibility [3][4][5][6]. FADAMA is one such repository and was developed to create a community-accessible resource with which forensic anthropologists can ask, analyze, and answer questions of casework and method performance on a community-wide scale [3].…”

“…However, it is important to note that these data sources are limited in their ability to speak to the holistic performance of forensic anthropology casework because they inherently exclude a large subset of caseworkunidentified cases. Thomas et al were one of the first to report a field-wide estimate of accuracy for sex [5] and ancestry [6], using FBI cases (identified and unidentified) derived from a diverse set of U.S. practitioners' casework. The authors concluded that casework's cumulative method outcomes were above 90% for both ancestry and sex.…”

Evaluating macroscopic sex estimation methods using genetically sexed archaeological material: The medieval skeletal collection from St John's Divinity School, Cambridge

“…Furthermore, in many societies biological sex is important in gender construction which is often a key aspect of social organization (Sofaer, ). While macroscopic methods currently used to estimate sex in archaeological remains are accurate when tested on postmedieval (1485–1800) and modern (1800 onwards) known‐sex individuals (e.g., Đuric, Rakočević, & Đonic, ; Lewis, Heather, & Gavin, ; Listi & Bassett, ; Mays & Cox, ; Meindl, Lovejoy, Mensforth, & Don Carlos, ; Thomas, Parks, & Richard, ; Ubelaker & Volk, ; Williams & Rogers, ), it could be argued that this high level of accuracy may reflect the fact that the populations tested are temporarily similar, or even the same collections used to create the methods.…”

“…As a result of improvements in aDNA methodology, computing power and declining costs, many large scale projects have produced genetic sex estimates (e.g., Altena, Smeding, & Knijff, ). This permits an assessment of the accuracy of macroscopic sex estimation methods for preindustrial populations, as has been done for forensic cases (Thomas et al, ). This will provide valuable information on the levels of sexual dimorphism for specific traits, which would be significant for improving macroscopic sex estimation methods.…”