Estimation and evidence in forensic anthropology: Sex and race

Journal of Forensic Sciences, 2021

Journal of Forensic Sciences, 2020

Recently, Drs. Bethard and DiGangi opened a dialogue on the application of ancestry estimation as part of the biological profile in forensic anthropology [1]. Ancestry estimation of human skeletal remains is routinely used to predict a probable social race based on metric and morphological data from the skeleton. Anthropologists accept the social construction of race and are acutely aware of its harmful impact in American society, particularly with respect to the historic use of anthropology to promote scientific racism. When scientists fail to 'call out' racist ideas in their field, these ideas can become embedded within institutions and society, further reifying racist ideology [2]. In this context, we wish to respond to Bethard and DiGangi's request to open a conversation regarding the use of ancestry estimation in forensic anthropology and how it contributes to the identification process. In this letter, we provide a foundation for a conversation about ancestry as a means to encourage thoughtful discussion moving forward on the issues of redress, diversity, and multidisciplinary collaboration.

American Journal of Physical Anthropology, 2009

American forensicanthropologists uncritically accepted the biological race concept from classic physical anthropology and applied it to methods of human identification. Why and how the biological race concept might work in forensic anthropology was contemplated by Sauer (Soc Sci Med 34 1992 107–111), who hypothesized that American forensic anthropologists are good at what they do because of a concordance between social race and skeletal morphology in American whites and blacks. However, Sauer also stressed that this concordance did not validate the classic biological race concept of physical anthropology that there are a relatively small number of discrete types of human beings. Results from Howells (Papers of the Peabody Museum of Archaeology and Ethnology 67 1973 1–259; Papers of the Peabody Museum of Archaeology and Ethnology 79 1989 1–189; Papers of the Peabody Museum of Archaeology and Ethnology 82 1995 1–108) and others using craniometric and molecular data show strong geographic patterning of human variation despite overlap in their distributions. However, Williams et al. (Curr Anthropol 46 2005 340–346) concluded that skeletal morphology cannot be used to accurately classify individuals. Williams et al. cited additional support from Lewontin (Evol Biol 6 1972 381–398), who analyzed classic genetic markers. In this study, multivariate analyses of craniometric data support Sauer's hypothesis that there are morphological differences between American whites and blacks. We also confirm significant geographic patterning in human variation but also find differences among groups within continents. As a result, if biological races are defined by uniqueness, then there are a very large number of biological races that can be defined, contradicting the classic biological race concept of physical anthropology. Further, our results show that humans can be accurately classified into geographic origin using craniometrics even though there is overlap among groups. Am J Phys Anthropol 2009. © 2009 Wiley-Liss, Inc.

Biology

One of the parameters forensic anthropologists have traditionally estimated is ancestry, which is used in the United States as a proxy for social race. Its use is controversial because the biological race concept was debunked by scientists decades ago. However, many forensic anthropologists contend, in part, that because social race categories used by law enforcement can be predicted by cranial variation, ancestry remains a necessary parameter for estimation. Here, we use content analysis of the Journal of Forensic Sciences for the period 2009–2019 to demonstrate the use of various nomenclature and resultant confusion in ancestry estimation studies, and as a mechanism to discuss how forensic anthropologists have eschewed a human variation approach to studying human morphological differences in favor of a simplistic and debunked typological one. Further, we employ modern geometric morphometric and spatial analysis methods on craniofacial coordinate anatomical landmarks from several L...

Forensic Anthropology, 2021

Forensic anthropologists traditionally estimate “race” or “ancestry” as part of the biological profile. While practitioners may have changed the terms used to describe regionally patterned human skeletal variation, the degree to which they have altered their typological approaches remains unclear. This study analyzed 119 peer-reviewed forensic anthropology articles published in four relevant journals (1966–2020) by matching combination(s) of the key words “race,” “ancestry,” “ethnicity,” and/or “population affinity.” Results indicated that while “ancestry” has supplanted “race,” this change has not brought concurrent modifications in approach, nor deeper scrutiny of underlying concepts. “Race” and “ancestry” were infrequently defined in 13% and 12% of sampled articles, respectively, and a plethora of social, geographic, and pseudoscientific terms persisted. Forensic anthropologists increasingly engaged with questions addressing the forces patterning human biological variation: 65% of studies postdating 1999 discussed population histories/structures and microevolution; 38% between 1966–1999. Fewer studies contextualized or critiqued approaches to analyzing population variation (32% of studies postdating 1999; 4% from 1966–1999), and virtually no studies considered the possibility that skeletal variation reflected embodied social inequity (5% of studies postdating 1999; 0% from 1966–1999). This lack of interrogation and clarity contributes to the faulty notion that all forensic anthropologists share similar definitions and leads to an oversimplification of complex biocultural processes. While the lack of definitions and biocultural engagement may be partly due to editorial and peer-review pressures, it is likely that many forensic anthropologists have not interrogated their own perspectives. This article holds that it is essential for us to do so.

Social Science & Medicine, 1992

Most anthropologists have abandoned the concept of race as a research tool and as a valid representation of human biological diversity. Yet, race identification continues to be one of the central foci of forensic anthropological casework and research. It is maintained in this paper that the successful assignment of race to a skeletal specimen is not a vindication of the race concept, but rather a prediction that an individual, while alive was assigned to a particular socially constructed 'racial' category. A specimen may display features that point to African ancestry. In this country that person is likely to have been labeled Black regardless of whether or not such a race actually exists in nature.

American Journal of Physical Anthropology, 2007

Forensic scientists are often expected to present the likelihood of DNA identifications in US courts based on comparative population data, yet forensic anthropologists tend not to quantify the strength of an osteological identification. Because forensic anthropologists are trained first and foremost as physical anthropologists, they emphasize estimation problems at the expense of evidentiary problems, but this approach must be reexamined. In this paper, the statistical bases for presenting osteological and dental evidence are outlined, using a forensic case as a motivating example. A brief overview of Bayesian statistics is provided, and methods to calculate likelihood ratios for five aspects of the biological profile are demonstrated. This paper emphasizes the definition of appropriate reference samples and of the ''population at large,'' and points out the conceptual in Wiley InterScience (www.interscience.wiley.com).

American Journal of Physical Anthropology, 2006

Forensic scientists are often expected to present the likelihood of DNA identifications in US courts based on comparative population data, yet forensic anthropologists tend not to quantify the strength of an osteological identification. Because forensic anthropologists are trained first and foremost as physical anthropologists, they emphasize estimation problems at the expense of evidentiary problems, but this approach must be reexamined. In this paper, the statistical bases for presenting osteological and dental evidence are outlined, using a forensic case as a motivating example. A brief overview of Bayesian statistics is provided, and methods to calculate likelihood ratios for five aspects of the biological profile are demonstrated. This paper emphasizes the definition of appropriate reference samples and of the “population at large,” and points out the conceptual differences between them. Several databases are introduced for both reference information and to characterize the “population at large,” and new data are compiled to calculate the frequency of specific characters, such as age or fractures, within the “population at large.” Despite small individual likelihood ratios for age, sex, and stature in the case example, the power of this approach is that, assuming each likelihood ratio is independent, the product rule can be applied. In this particular example, it is over three million times more likely to obtain the observed osteological and dental data if the identification is correct than if the identification is incorrect. This likelihood ratio is a convincing statistic that can support the forensic anthropologist's opinion on personal identity in court. Am J Phys Anthropol, 2006. © 2006 Wiley-Liss, Inc.

Journal of Forensic Sciences, 2021

The purpose of this study was to investigate the accuracy rates and trends in forensic anthropology casework concerning the estimation of the biological profile (sex, age, ancestry, and stature). Identified cases from the Forensic Anthropology Database for Assessing Methods Accuracy (FADAMA; n = 359) were analyzed to explore the following: accuracy rates per biological profile component, case-level performance in assessing the biological profile, and factors related to inaccuracy rates. Accuracy rates for the four biological profile components ranged from 83% to 98%, with sex estimation performing the best and stature performing the poorest. While the overall sex estimation inaccuracies were the lowest of any biological profile component, we found that females are missexed approximately ten times more often than males. Inaccurate age estimates were more frequently the result of overestimation than underestimation, while the trends are reversed for stature estimation. Regarding ancestry estimation performance, African American/Black and White decedents had the lowest inaccuracy rates, while Hispanic and Asian/Pacific Islander decedents demonstrated greater inaccuracy rates. When examining accuracy rates for each case, 81% of cases had no inaccurate biological profile estimates, while 17% and 2% inaccurately estimated one and two biological profile components, respectively. The demographic trends of identified forensic anthropology cases reflect the national unidentified decedent demographics. Biological profile accuracy rates were generally comparable to previous studies. The findings highlight the current status of forensic anthropologists’ casework performance, with a greater amount of case-level inaccuracy rates than previously thought, and demonstrate the potential methodological and sampling strategies that could improve accuracy rates.

Journal of forensic sciences, 2017

A common task in forensic anthropology involves the estimation of the ancestry of a decedent by comparing their skeletal morphology and measurements to skeletons of individuals from known geographic groups. However, the accuracy rates of ancestry estimation methods in actual forensic casework have rarely been studied. This article uses 99 forensic cases with identified skeletal remains to develop accuracy rates for ancestry estimations conducted by forensic anthropologists. The overall rate of correct ancestry estimation from these cases is 90.9%, which is comparable to most research-derived rates and those reported by individual practitioners. Statistical tests showed no significant difference in accuracy rates depending on examiner education level or on the estimated or identified ancestry. More recent cases showed a significantly higher accuracy rate. The incorporation of metric analyses into the ancestry estimate in these cases led to a higher accuracy rate.