Erin H. Kimmerle

Sexual dimorphism in America: geometric morphometric analysis of the craniofacial region.

Abstract:  One of the four pillars of the anthropological protocol is the estimation of sex. The protocol generally consists of linear metric analysis or visually assessing individual skeletal traits on the skull and pelvis based on an ordinal scale of 1–5, ranging from very masculine to very feminine. The morphologic traits are then some how averaged by the investigator to estimate sex. Some skulls may be misclassified because of apparent morphologic features that appear more or less robust due to size differences among individuals. The question of misclassification may be further exemplified in light of comparisons across populations that may differ not only in cranial robusticity but also in stature and general physique. The purpose of this study is to further examine the effect of size and sex on craniofacial shape among American populations to better understand the allometric foundation of skeletal traits currently used for sex estimation. Three‐dimensional coordinates of 16 standard craniofacial landmarks were collected using a Microscribe‐3DX digitizer. Data were collected for 118 American White and Black males and females from the W.M. Bass Donated Collection and the Forensic Data Bank. The MANCOVA procedure tested shape differences as a function of sex and size. Sex had a significant influence on shape for both American Whites (F = 2.90; d.f. = 19, 39; p > F = 0.0024) and Blacks (F = 2.81; d.f. = 19, 37; p > F = 0.0035), whereas size did not have a significant influence on shape in either Whites (F = 1.69; d.f. = 19, 39; p > F = 0.08) or Blacks (F = 1.09; d.f. = 19, 37; p > F = 0.40). Therefore, for each sex, individuals of various sizes were statistically the same shape. In other words, while significant differences were present between the size of males and females (males on average were larger), there was no size effect beyond that accounted for by sex differences in size. Moreover, the consistency between American groups is interesting as it suggests that population differences in sexual dimorphism may result more from human variation in size than allometric variation in craniofacial morphology.

Estimation and Evidence in Forensic Anthropology: Age‐at‐Death

Abstract:  A great deal has previously been written about the use of skeletal morphological changes in estimating ages‐at‐death. This article looks in particular at the pubic symphysis, as it was historically one of the first regions to be described in the literature on age estimation. Despite the lengthy history, the value of the pubic symphysis in estimating ages and in providing evidence for putative identifications remains unclear. This lack of clarity primarily stems from the fact that rather ad hoc statistical methods have been applied in previous studies. This article presents a statistical analysis of a large data set (n = 1766) of pubic symphyseal scores from multiple contexts, including anatomical collections, war dead, and victims of genocide. The emphasis is in finding statistical methods that will have the correct “coverage.”“Coverage” means that if a method has a stated coverage of 50%, then approximately 50% of the individuals in a particular pubic symphyseal stage should have ages that are between the stated age limits, and that approximately 25% should be below the bottom age limit and 25% above the top age limit. In a number of applications it is shown that if an appropriate prior age‐at‐death distribution is used, then “transition analysis” will provide accurate “coverages,” while percentile methods, range methods, and means (±standard deviations) will not. Even in cases where there are significant differences in the mean ages‐to‐transition between populations, the effects on the stated age limits for particular “coverages” are minimal. As a consequence, more emphasis needs to be placed on collecting data on age changes in large samples, rather than focusing on the possibility of inter‐population variation in rates of aging.

Analysis of Age-at-Death Estimation Through the Use of Pubic Symphyseal Data*

Abstract:  The question of whether age parameters derived from an American population will reliably estimate age‐at‐death for East European skeletal populations is important since the ability to accurately estimate an individual’s age‐at‐death hinges on what standard is used. A reference sample of identified individuals with known ages‐at‐death from the regions of the Former Yugoslavia (n = 861) is used to determine the age structure of victims and serves as the prior in the Bayesian analysis. Pubic symphyseal data in the manners of Todd (Am J Phys Anthropol, 3 [1920], 285; Am J Phys Anthropol, 4 [1921], 1) and Suchey‐Brooks (Am J Phys Anthropol, 80 [1986], 167) were collected for n = 296 Balkan males and females and for n = 2078 American males and females. An analysis of deviance is calculated using an improvement chi‐square to test for population variation in the aging processes of American and East European populations using proportional odds probit regression. When males and females are treated separately, there is a significant association among females and the population (df = 1, chi‐square likelihood ratio = 15.071, p = 0.001). New age estimates for Balkan populations are provided and are based on the calculated age distribution from the Gompertz‐Makeham hazard analysis and the ages‐of‐transition. To estimate the age‐at‐death for an individual, the highest posterior density regions for each symphyseal phase are provided.

A new method for estimating age-at-death from the first rib.

A new method for estimating adult age-at-death from the first rib was developed as a modification of the Kunos et al. (Am J Phys Anthropol 110 (1999) 303-323) method. Data were collected on three aspects of the first rib (costal face, rib head, and tubercle facet) for 470 known-age males of Balkan ancestry collected as evidence during investigations conducted by the International Criminal Tribunal for the former Yugoslavia (ICTY). Ages-at-death range from 12 to 90 years (mean of 47.7 years). Several variables were extracted from the original study utilizing all three skeletal aspects of the first rib. This list was modified to 11 variables as preliminary tests on seriations of the samples were undertaken. A cumulative probit model with age measured on a log scale was used to calculate the mean and standard deviation of the ages-of-transition for each component. Multivariate analysis of the three components was also performed. The lowest correlation (r = 0.079, controlling for age) was between the geometric shape of the costal face and the surface texture of the tubercle facet. Assuming a correlation of zero, these two traits were used to calculate the highest posterior density regions for estimating individual ages-at-death. Age-at-death estimates generated from 50 and 95% posterior density regions indicate that this method captures age-related change reaching the ninth decade. The Bayesian statistical approach used here produced a valuable and promising new method for estimating age-at-death. Additional research is necessary to determine if these highest posterior density regions produce results highly correlated with age in other samples and its applicability to females.

Skeletal Estimation and Identification in American and East European Populations

Abstract:  Forensic science is a fundamental transitional justice issue as it is imperative for providing physical evidence of crimes committed and a framework for interpreting evidence and prosecuting violations to International Humanitarian Law (IHL). The evaluation of evidence presented in IHL trials and the outcomes various rulings by such courts have in regard to the accuracy or validity of methods applied in future investigations is necessary to ensure scientific quality. Accounting for biological and statistical variation in the methods applied across populations and the ways in which such evidence is used in varying judicial systems is important because of the increasing amount of international forensic casework being done globally. Population variation or the perceived effect of such variation on the accuracy and reliability of methods is important as it may alter trial outcomes, and debates about the scientific basis for human variation are now making their way into international courtrooms. Anthropological data on population size (i.e., the minimum number of individuals in a grave), demographic structure (i.e., the age and sex distribution of victims), individual methods applied for identification, and general methods of excavation and trauma analysis have provided key evidence in cases of IHL. More generally, the question of population variation and the applicability of demographic methods for estimating individual and population variables is important for American and International casework in the face of regional population variation, immigrant populations, ethnic diversity, and secular changes. The reliability of various skeletal aging methods has been questioned in trials prosecuted by the International Criminal Tribunal for the Former Yugoslavia (ICTY) in The Prosecutor of the Tribunal against Radislav Krstiċ (Case No. IT‐98‐33, Trial Judgment) and again in the currently ongoing trial of The Prosecutor of the Tribunal against Zdravko Tolimir, Radivolje Miletiċ, Milan Gvero, Vinko Pandureviċ, Ljubisa Beara, Vujadin Popoviċ, Drago Nikoliċ, Milorad Trbiċ, Ljubomir Borovcanin (IT‐05‐88‐PT, Second Amended Indictment). Following the trial of General Krstiċ, a collaborative research project was developed between the Forensic Anthropology Center at The University of Tennessee (UT) and the United Nations, International Criminal Tribunal for the Former Yugoslavia, Office of the Prosecutor (ICTY). The purpose of that collaboration was to investigate methods used for the demographic analysis of forensic evidence and where appropriate to recalibrate methods for individual estimation of age, sex, and stature for specific use in the regions of the former Yugoslavia. The question of “local standards” and challenges to the reliability of current anthropological methods for biological profiling in international trials of IHL, as well as the performance of such methods to meet the evidentiary standards used by international tribunals is investigated. Anthropological methods for estimating demographic parameters are reviewed. An overview of the ICTY‐UT collaboration for research aimed at addressing specific legal issues is discussed and sample reliability for Balkan aging research is tested. The methods currently used throughout the Balkans are discussed and estimated demographic parameters obtained through medico‐legal death investigations are compared with identified cases. Based on this investigation, recommendations for improving international protocols for evidence collection, presentation, and research are outlined.

Implications of dimorphism, population variation, and secular change in estimating population affinity in the Iberian Peninsula.

Morphometric cranial variation among Spanish samples was compared to a 19th century Portuguese sample using both traditional and three-dimensional approaches. The Spanish samples included the regional 19th century Oloriz collection and the local 16-17th century Villanubla and Vallolid sample from northwestern Spain. Results suggest moderate variation among the samples and suggest that varying patterns of regional variation, sexual dimorphism and secular change represent important factors to be considered in the evaluation of population affinity using craniometric approaches.

A Bayesian approach to estimate skeletal age-at-death utilizing dental wear.

Abstract:  In the forensic context, teeth are often recovered in mass disasters, armed conflicts, and mass graves associated with human rights violations. Therefore, for victim identification, techniques utilizing the dentition to estimate the first parameters of identity (e.g., age) can be critical. This analysis was undertaken to apply a Bayesian statistical method, transition analysis, based on the Gompertz–Makeham (GM) hazard model, to estimate individual ages‐at‐death for Balkan populations utilizing dental wear. Dental wear phases were scored following Smith’s eight‐phase ordinal scoring method and chart. To estimate age, probability density functions for the posterior distributions of age for each tooth phase are calculated. Transition analysis was utilized to generate a mean age‐of‐transition from one dental wear phase to the next. The age estimates are based on the calculated age distribution from the GM hazard analysis and the ages‐of‐transition. To estimate the age‐at‐death for an individual, the highest posterior density region for each phase is calculated. By using a Bayesian statistical approach to estimate age, the population’s age distribution is taken into account. Therefore, the age estimates are reliable for the Balkan populations, regardless of population or sex differences. The results showed that a vast amount of interpersonal variation in dental wear exists within the current sample and that this method may be most useful for classifying unknown individuals into broad age cohorts rather than small age ranges.

Sexing and Stature Estimation Criteria for Balkan Populations

Abstract:  Two standard measurements, maximum femur length and head diameter, were collected by International Criminal Tribunal (ICTY) anthropologists. Only Kosovans had both femur dimensions for both sexes. Antemortem stature data were available only for Kosovan and Croatian males. Despite these limitations, the data offer the opportunity to examine ethnic variation and to present sex and stature estimation criteria for these groups. Additional data from Croatians and from American Whites were used for comparison in certain parts of the analysis. Femur variation was considerable. Kosovans can be characterized as short and robust, Bosnians as tall and less robust, and Croatians are tall and gracile, resembling American Whites more than the other groups. Some limited antemortem data on stature was also available, allowing stature estimation equations to be estimated for Croatians and Kosovans. Antemortem stature estimates were obtained from interviews with relatives and are shown to overestimate actual stature. We argue that equations predicting height obtained from relatives is the most realistic in this case because that is the height to which an estimate obtained from bone lengths will be compared. Kosovans were also shown to have experienced slight secular increase in femur length over the past 70 years.

Variation as Evidence: Introduction to a Symposium on International Human Identification

In the on-going genocide trial of The Prosecutor v. Popovi_ c et al. (IT-05-88-PT) (1), demographic evidence about the population structure of victims has again been challenged. How the Trial Chamber views this evidence has yet to be determined, but this is not the first time in a criminal case of genocide that anthropological evidence about the number of victims or age and sex distribution of multiple victims has been under scrutiny. In the case of The Prosecutor v. Radislav Krsti_ c (Case No. IT-98-33, Judgment, August 2, 2001; Appeals Chamber Judgment, April 19, 2004) (2), the defense attorney also challenged demographic evidence presented by the prosecution and in doing so, differed markedly from American homicide trials. In American criminal trials, methods for identification have often been challenged when they are used to identify the perpetrator of a crime such as the use of fingerprints or DNA to link a suspect to the scene or victim. In contrast, among international trials of violations to International Humanitarian Law (IHL), particularly in cases involving charges of genocide or conspiracy to commit genocide, the identity of the victims rather than the perpetrators has been primarily at issue. Genocide is defined in Article II of the Convention on the Prevention and Punishment of the Crime of Genocide (Adopted by Resolution 260 (III) A of the U.N. General Assembly on 9 December 1948, Entry into force: 12 January 1951), which states:

Immigrants, Undocumented Workers, Runaways, Transients and the Homeless: Towards Contextual Identification Among Unidentified Decedents

Abstract The pool of persons who go missing and subsequently become part of the unidentified population is predominately adult, male, underrepresented minorities, foreign-born individuals, and people from at-risk groups. In particular, a growing obstacle to the identification of unidentified decedents (UIDs) is the increase of foreign-born immigrants, including migrant workers and undocumented persons in the United States. Increasingly, individuals of foreign-born nationality are an important component in UID cases as there may not be access to information about who is missing, personal data about the decedent, nor family members available to aid the identification process. The demographic structures, mobility patterns, and contextual factors about unidentified cases are compared to those who have been identified. Data comes from both solved and open cases from forensic anthropology laboratories at the University of South Florida, the C.A. Pound Human Identification Laboratory at the University of Florida, the Forensic Data Bank maintained at The University of Tennessee, and the Medical Examiners Offices of Georgia. Recommendations for policy are further discussed, such as the application of population-based research strategies that account for biological and cultural variation related to identification parameters; the development of a bilingual searchable databases with anonymous information submittal capabilities; and the incorporation of biological information about the decedent along with possible biological traits and personal or cultural artifacts, such as descriptions and photographs of personal effects, tattoos, and facial approximations, into searchable Web-based databases that facilitate the monumental task of identifying UID in a way that is appropriate given the population in question.