Evaluating population affinity estimates in forensic anthropology: Insights from the forensic anthropology database for assessing methods accuracy (FADAMA)

Abstract

Using a sample of anonymized U.S. forensic anthropology cases (n = 251) from the FADAMA database, we assess the degree of concordance between decedents' social identifiers and anthropologists' continental-based classifications. We report high success rates (>90%) that generally support previous findings, yet we acknowledge the limitations of assessing "ancestry" accuracy based on resolved cases and draw attention to situations in which our methods fail. For example, forensic anthropologists achieve just 20% accuracy when classifying individuals as "other" or "mixed"-problematic categories that we argue should be rejected. Leveraging our findings, we ask: what are we really estimating when we perform a skeletal assessment of "ancestry" in the US context?We argue that the "ancestry estimates" historically and routinely produced in forensic anthropology instead give information on population affinity: a measure of how similar a given case is to one among several socially relevant groups of interest. Distancing forensic anthropology from genetics and other disciplines that estimate ancestry, the approach of population affinity assesses similarities to both social and biological groupings, potentially at a fine-grained level, attempting to account for the complex histories, shared biologies, and wide ranges of diversity that characterize our communities and our casework. Population affinity is a flexible and inclusive approach that more accurately describes current forensic anthropological analyses of human variation. Going forward, we must acknowledge and build on the contributions of previous scholars as we work together toward our shared goal of theoretically grounded analyses of human variation that accurately and equitably serve all casework decedents.

Frontal Sinus Morphological and Dimensional Variation as Seen on Computed Tomography Scans

“…While imprecise, this proxy is described using the term “population affinity”—referred to as “ancestry” in many studies—and samples herein are designated based on where an individual is biogeographically derived from: African-derived, Asian-derived, European-derived, and Latin American-derived. Terms like “race” have been used in previous studies; however, race is a social concept and does not adequately account for or explain human biological variation [ 71 ]. Historically, forensic anthropologists have used “ancestry” synonymously with social race and have used terms like “Hispanic” to describe an individual’s ancestral lineage.…”

“…Historically, forensic anthropologists have used “ancestry” synonymously with social race and have used terms like “Hispanic” to describe an individual’s ancestral lineage. Now, these terms and classifications of human groups are being critiqued and reanalyzed, and there has been a shift in practitioners’ perspectives regarding the efficacy and role of ancestry estimation [ 71 , 72 , 73 , 74 ]. Similarly, the discussion of assigned sex, gender, and the terminology surrounding these categories is currently being evaluated [ 75 , 76 ].…”

Implementing an antiracist framework in forensic anthropology: Our responsibility in professional organizations and as scientists

“…When considering ancestry specifically, the following promote equity by challenging racist systems: more nuanced understandings of population affinity and morphological variation (Clemmons 2022; Go and Hefner 2020; Herrera and Tallman 2019; Kelley and Tallman 2022; Kilroy, Tallman, and DiGangi 2020), diversifying gene banks and skeletal reference samples and understanding why those reference samples lack diversity (Winburn et al. 2022), incorporating more inclusive and less harmful terminology (Maier, Craig, and Adams 2021; Tallman, Parr, and Winburn 2021; Winburn and Algee‐Hewitt 2021), considering social factors when ancestry is translated into a probable racial label and studying the effects of those labels (Smay and Armelagos 2000), applying critical race theory and other biocultural theoretical frameworks into research and practice (Ross and Pilloud 2021; Tallman and Bird 2022; Tallman, Kincer, and Plemons 2022; Tallman, Parr, and Winburn 2021; Winburn, Martinez, and Schoff 2017; Winburn, Schoff, and Warren 2016), and, for some, calling for the wholesale elimination of ancestry estimation in forensic anthropology casework due to systemic racial biases and white supremacy inherent in the methodological and investigative processes (Bethard and DiGangi 2020; DiGangi and Bethard 2021). These initiatives improve the quality and standards of forensic anthropology—a primary role of the AAFS—as these efforts aim to revise inaccuracies in existing knowledge and incorporate new data into wider, socially relevant theoretical frameworks.…”

The need to incorporate human variation and evolutionary theory in forensic anthropology: A call for reform

“…She further identified issues with how race was reported antemortem and how it was reported biologically. Accuracy is probably much lower, as many individuals remain unidentifiedpossibly because of incorrect assessments (Winburn & Algee-Hewitt, 2021).…”