Evidentiary Standards for Forensic Anthropology*

Abstract: As issues of professional standards and error rates continue to be addressed in the courts, forensic anthropologists should be proactive by developing and adhering to professional standards of best practice. There has been recent increased awareness and interest in critically assessing some of the techniques used by forensic anthropologists, but issues such as validation, error rates, and professional standards have seldom been addressed. Here we explore the legal impetus for this trend and identify areas where we can improve regarding these issues. We also discuss the recent formation of a Scientific Working Group for Forensic Anthropology (SWGANTH), which was created with the purposes of encouraging discourse among anthropologists and developing and disseminating consensus guidelines for the practice of forensic anthropology. We believe it is possible and advisable for anthropologists to seek and espouse research and methodological techniques that meet higher standards to ensure quality and consistency in our field.     

The Contribution of Body Mass and Volume of Distribution to the Estimated Uncertainty Associated with the Widmark Equation

The Widmark equation is used forensically for the determination of the amount of ethanol (alcohol) that may have been consumed and also to determine the blood alcohol concentration (BAC) of an individual at a specific time. It is important to be able to estimate the uncertainty associated with Widmark equations. To date, there has been no detailed determination of contribution to the final uncertainty of Widmark calculations of the volume of distribution of ethanol (V_d), using anthropometric equations, or the contribution of an individual’s body mass. Using published data, published literature, and freedom of information data, we determined that the variability (%CV) associated with V_d was ~10% (Watson et al. and Forrest anthropometric equations) and that the %CV associated with estimated body mass was ~15% compared to ~3% when body mass was directly measured. These data allow an estimation of the overall uncertainty of Widmark calculations using general error propagation. The estimated total uncertainty for BAC calculations increased from ~11% (volume consumed) and ~22% (BAC) to ~19% (volume consumed) and ~37% (BAC) when using measured body mass compared to estimated body mass. These results demonstrate that forensic practitioners should be mindful of the increase in estimated uncertainty in calculated Widmark equation results when estimated body mass is used rather than measured body mass. These data further improve the knowledge around the uncertainty of results calculated with the Widmark equation.     

The use of error rates to predict and characterize the efficacy of presumptive field tests

From a forensic perspective, a presumptive test, one which indicates the presence or absence of a certain target material such as blood, is an invaluable tool. Among these tests, there are different specificities, sensitivities, and shelf lives. The accuracy of a test is an algebraic combination of the specificity and sensitivity of the test. Each test has limitations as given by its false positive and false negative rates. The aim of this study was to illustrate how the false positive and false negative rates are to be properly determined using a simulation study for the phenolphthalein test. New presumptive tests must be properly evaluated/validated through testing of commonly encountered household items and other potentially probative items usually found at crime scenes, however, the makeup of test sets must appropriately capture all error rates. In order to correctly use these results when the test is applied to an unknown sample recovered at a crime scene, the error rates cannot be applied directly to estimate whether or not the sample is actually the analyte of interest. In a validation study, the forensic scientist calculates the false positive rate as the p(Positive Reaction|Blood), whereas at the scene, the crime scene investigator wishes to determine the p(Blood|Positive Reaction). All crime scene investigators need to ensure that the conditional is not transposed when interpreting such results. Furthermore, this work provides a model for the assessment of a multiple test diagnostic system intended for investigators.     

Analysis of histomorphometric variables: Proposal and validation of osteon definitions

Histological analysis of bone tissue has been used to explore a variety of questions relating to age-at-death, habitual behaviors, health, and nutritional stress. Identification of intact and fragmentary osteons is of key interest to many researchers in these studies, yet the definitions of these features vary between researchers making cross-study comparisons problematic. Furthermore, histological variable definitions are often ambiguous or require subjective classifications by the observer. As a result, and as indicated by previous studies, observer error and misclassification of certain variables, namely intact and fragmentary osteons, can be significant. This study proposes new definitions for intact and fragmentary osteons that are designed to limit observer subjectivity and also explore efficacy of combining osteon types into one variable. A sample of 30 6th rib cross-sections from a modern forensic population was used to test the validity of the proposed definitions. Observations of intact osteon population density (OPD(I)) and fragmentary osteon population density (OPD(F)) were made by three observers for each cross-section. These observations were used to explore the interobserver error associated with the proposed definitions and determine if combining variables into one variable (OPD) mitigates persisting classification difficulties. Results indicate that the proposed definitions significantly reduce interobserver error and misclassification of intact and fragmentary osteons. However, the interobserver error associated with fragmentary osteons is still high. Evaluation of the variables independently indicates that combining variables has potential to reduce the predictive strength of an age estimation model and the ability to interpret age-related bone remodeling.     

Addressing the National Academy of Sciences' challenge: a method for statistical pattern comparison of striated tool marks

In February 2009, the National Academy of Sciences published a report entitled "Strengthening Forensic Science in the United States: A Path Forward." The report notes research studies must be performed to "…understand the reliability and repeatability…" of comparison methods commonly used in forensic science. Numerical classification methods have the ability to assign objective quantitative measures to these words. In this study, reproducible sets of ideal striation patterns were made with nine slotted screwdrivers, encoded into high-dimensional feature vectors, and subjected to multiple statistical pattern recognition methods. The specific methods employed were chosen because of their long peer-reviewed track records, widespread successful use for both industry and academic applications, rely on few assumptions on the data's underlying distribution, can be accompanied by standard confidence levels, and are falsifiable. For PLS-DA, correct classification rates of 97% or higher were achieved by retaining only eight dimensions (8D) of data. PCA-SVM required even fewer dimensions, 4D, for the same level of performance. Finally, for the first time in forensic science, it is shown how to use conformal prediction theory to compute identifications of striation patterns at a given level of confidence.     

案例教学法在卫生法学教学实施中的误区及解决策略

案例教学法在部分院校的卫生法教学实施中取得了良好的效果,但其教学设计、教学实施及教学反思环节仍存在误区。应当在以学生为主的教学理念和重视双向交流原则的指导下,通过精选教学案例、营造良好的课堂教学氛围、规范教学步骤来完善教学设计环节,通过突出学生学习的实践性和关注案例所涉知识面的扩展来重构教学实施环节,通过重视对本次案例教学法适用的总结反思和对整门学科适用案例教学法质量的检测来关注教学反思环节。     

Human Factors Effecting Forensic Decision Making: Workplace Stress and Well‐being

Over the past decade, there has been a growing openness about the importance of human factors in forensic work. However, most of it focused on cognitive bias, and neglected issues of workplace wellness and stress. Forensic scientists work in a dynamic environment that includes common workplace pressures such as workload volume, tight deadlines, lack of advancement, number of working hours, low salary, technology distractions, and fluctuating priorities. However, in addition, forensic scientists also encounter a number of industry‐specific pressures, such as technique criticism, repeated exposure to crime scenes or horrific case details, access to funding, working in an adversarial legal system, and zero tolerance for “errors”. Thus, stress is an important human factor to mitigate for overall error management, productivity and decision quality (not to mention the well‐being of the examiners themselves). Techniques such as mindfulness can become powerful tools to enhance work and decision quality.     

媒体报道85起医疗过失精神损害赔偿费分析

目的　探讨医疗过失索赔精神损失费 85起案例的特点 ,并提出相应的建议。　方法　采用回顾性调查方法对从 1996年 2月至 2 0 0 1年 6月报刊杂志上收集的 85例医疗过失索赔精神损失案件进行分析 ,按照医疗过失涉及的科室、发生医院的等级、索赔额与实际赔偿额等因素进行统计量化处理。　结果　媒体报道的索赔精神损失费案件中 ,手术科室和用血监测部门是医疗过失涉及的主要场所 ;大医院是发生医疗过失的主要场所 ,在美容损害中诊所、美容院中发生为多见 ;精神损失索赔额大多数目巨大 ;精神损失赔偿的实际赔偿额远低于索赔额。　结论　通过对 85起案例的分析 ,提出如下对策 :(1)必须加强对手术科室和用血监测的管理 ;(2 )精神损害赔偿的法规需进一步完善 ;(3)新闻报道要增强社会责任感 ,在维护患方权益的同时 ,也要切实保护医方的利益。     

Measurement and Other Errors in County-Level UCR Data: A Reply to Lott and Whitley

Lott and Whitley note that our analyses of the errors in the county-level UCR data used in More Guns, Less Crime (J. R. Lott, University of Chicago Press, Chicago, 1998, 2000) ignore the fact that all data have measurement error, that the largest errors were in counties with low populations, and that population-weighted regressions were used. We agree that this mitigates some of the effects of the errors, but does not take them fully into account. We also note that this is but one of the problems associated with the analysis. We therefore find no reason to alter our original conclusion, that in their current condition, county-level UCR crime statistics cannot be used for evaluating the effects of changes in policy.     

合同因错误而撤销的信赖赔偿责任

合同因错误而被撤销,撤销人应负担信赖赔偿责任。该制度渊源于罗马法,历经德国学者温德夏特、耶林、贝尔、梅尔的建构,最终在1896德国民法典中确立,并被现代各国民法继受。错误信赖赔偿责任是信赖保护的重要制度。它不同于缔约过失责任,不以过失为要件,而以信赖为归责原则,具有独立的构成要件和适用范围。它是一种独立的责任形态,旨在追求公平理念。我国应当确立错误信赖赔偿责任。