Drug Testing and Procedural Fairness: The Influence of Situational Variables

This study examines the effect of four variables (i.e., interpersonal treatment, organizational reputation, testing context, and consequence of testing) on perceptions of the procedural fairness of a drug-testing program. Main effects for each of these variables on perceptions of procedural fairness were expected. In addition, interactions were predicted between interpersonal treatment and organizational reputation, testing context and consequence, and testing context and interpersonal treatment. Results generally supported the hypotheses, revealing main effects for the four variables and two significant interactions. The implications of these findings for justice research and the design and implementation of drug-testing programs are discussed.     

Using the Nondonor Distribution to Improve Communication and Inform Decision Making for Low LRs from Minor Contributors in Mixed DNA Profiles

The reporting of a likelihood ratio (LR) calculated from probabilistic genotyping software has become more popular since 2015 and has allowed for the use of more complex mixtures at court. The meaning of “inconclusive” LRs and how to communicate the significance of low LRs at court is now important. We present a method here using the distribution of LRs obtained from nondonors. The nondonor distribution is useful for examining calibration and discrimination for profiles that have produced LRs less than about 10⁴. In this paper, a range of mixed DNA profiles of varying quantity were constructed and the LR distribution considering the minor contributor for a number of nondonors was compared to the expectation given a calibrated system. It is demonstrated that conditioning genotypes should be used where reasonable given the background information to decrease the rate of nondonor LRs above 1. In all 17 cases examined, the LR for the minor donor was higher than the nondonor LRs, and in 12 of the 17 cases, the 99.9 percentile of the nondonor distribution was lower when appropriate conditioning information was used. The output of the tool is a graph that can show the position of the LR for the person of interest set against the nondonor LR distribution. This may assist communication between scientists and the court.     

Development and Implementation of an Effective Blind Proficiency Testing Program

Blind proficiency testing is ideal for testing crime laboratory personnel because the elements of analyst bias and anticipation are removed. However, sending proficiency tests through the laboratory system as real casework is difficult. The substantial challenges with preparing and administering blind tests may prevent laboratory managers from initiating blind testing. In 2015, the Harris County Institute of Forensic Sciences committed to improving its crime laboratory’s proficiency testing program by adding blind tests. The goal was to test the whole system, from evidence receipt to report release. With careful planning, trial-and-error, and ongoing assessment of available resources, not only was the program proven to be feasible, but there was also clear understanding of how to optimize our program. In this article, we share our experiences, lessons learned, and program details to assist other forensic service providers with developing their own blind testing programs, which would ultimately lead to improved quality assurance.     

Latent Print Proficiency Testing: An Examination of Test Respondents,Test-Taking Procedures,and Test Characteristics

Proficiency testing is a key component of quality assurance programs within crime laboratories and can help improve laboratory practices. However, current proficiency testing procedures contain significant limitations and can be misinterpreted by examiners and court personnel (Garrett & Mitchell, 2018). To evaluate some of these limitations, we surveyed latent print examiners (n = 198) after they completed a Collaborative Testing Services, Inc. proficiency test. Additionally, we evaluated test performance and used a quality metric algorithm to evaluate the quality of test prints. Results do not suggest that respondents are dissimilar to the broader examiner population, although they may engage in different behaviors when completing tests versus casework. Findings show that proficiency testing contains prints of high quality and is perceived as both relatively easy and representative of casework. The test discriminated between inexperienced and experienced respondents, and verification procedures were largely ineffective in reducing errors. Objective quality metrics may provide a path forward to improving proficiency testing in a measurable manner.     

Identification of Opioids and Related Substances using Handheld Raman Spectrometers

This study describes the performance of handheld Raman devices for detecting one hundred opioids and related substances including fentanyl and several analogs. Using a single “parent” device, signatures (spectra) with excellent signal-to-noise ratios were generated using <5 mg of most compounds. The signatures were added to a method (library), which was electronically transferred to three “daughter” devices. The devices were able to discriminate different salt forms and isomers. On average, the daughter devices yielded a true-positive rate of 97.3% for generating an alarm for opioids and were 93.3% effective for correctly identifying the opioid. The devices yielded true-negative, false-positive and false-negative rates of 100%, 0%, and 2.7%, respectively, where false negatives were due to weak signal and fluorescence. These data demonstrate that the parent-daughter electronic transfer method was successful and effective, which permits the ability to develop methods in the laboratory that can be seamlessly pushed out to field devices.     

How do latent print examiners perceive proficiency testing? An analysis of examiner perceptions,performance, and print quality

Proficiency testing has the potential to serve several important purposes for crime laboratories and forensic science disciplines. Scholars and other stakeholders, however, have criticized standard proficiency testing procedures since their implementation in laboratories across the United States. Specifically, many experts label current proficiency tests as non-representative of actual casework, at least in part because they are not sufficiently challenging (e.g., [1], [2], [3], [4]. In the current study, we surveyed latent print examiners (n = 322) after they completed a Collaborative Testing Services proficiency test about their perceptions of test items. We also evaluated respondents’ test performance and used a quality metric algorithm (LQMetrics) to obtain objective indicators of print quality on the test. Results were generally consistent with experts’ concerns about proficiency testing. The low observed error rate, examiner perceptions of relative ease, and high objective print quality metrics together suggest that latent print proficiency testing is not especially challenging. Further, examiners indicated that the test items that most closely resembled real-world casework were also the most difficult and contained prints of the lowest quality. Study findings suggest that including prints of lower quality may increase both the difficulty and representativeness of proficiency testing in latent print examination.     

ISFG: Recommendations on biostatistics in paternity testing

The Paternity Testing Commission (PTC) of the International Society for Forensic Genetics has taken up the task of establishing the biostatistical recommendations in accordance with the ISO 17025 standards and a previous set of ISFG recommendations specific to the genetic investigations in paternity cases. In the initial set, the PTC recommended that biostatistical evaluations of paternity are based on a likelihood ratio principle – yielding the paternity index, PI. Here, we have made five supplementary biostatistical recommendations. The first recommendation clarifies and defines basic concepts of genetic hypotheses and calculation concerns needed to produce valid PIs. The second and third recommendations address issues associated with population genetics (allele probabilities, Y-chromosome markers, mtDNA, and population substructuring) and special circumstances (deficiency/reconstruction and immigration cases), respectively. The fourth recommendation considers strategies regarding genetic evidence against paternity. The fifth recommendation covers necessary documentation, reporting details and assumptions underlying calculations. The PTC strongly suggests that these recommendations should be adopted by all laboratories involved in paternity testing as the basis for their biostatistical analysis.     

从命令到规则:哈特对奥斯丁的批判——读哈特《法律的概念》

哈特试图以法律的规则学说取代奥斯丁的法律命令理论,这一理论努力的背后所隐含的正是法律实证主义的某些深刻且基本的问题意识。通过分析哈特对奥斯丁的批判,我们比较了两种版本的法律实证主义在法律的存在方式以及检验法律的标准这两个问题上给出的不同回答,在此基础上提出,哈特的规则学说并没有能够真正地取代奥斯丁的命令理论,规则与命令所表明的可能是法律存在方式也即法律与社会生活方式联结的不同方面。     

浅谈犯罪心理测试技术

犯罪心理测试技术在刑事侦查活动中发挥着重要作用 ,但侦查机关在运用犯罪心理测试技术时存在一些问题 ,侦查机关应加强对犯罪心理测试的配合。而测试人员应注意严格把握测试条件 ,选择最佳测试时间 ,结合具体情况开发准绳问题和在测前谈话和测后谈话中为测后审讯打好基础     

An Illicit Love Affair During the Third Reich: Who is My Grandfather?*

More than 60 years after an illicit love affair had occurred between Erika H, wife of a Wehrmacht soldier, and a Polish slave worker during World War II, we could clarify the blood relationships of her daughter Uta. When Erika H had become pregnant both of the men could have fathered the child. Erika H was found guilty of fraternization and imprisoned at Ravensbrück concentration camp. She gave birth to Uta and died there in 1944. Uta survived the war as did Erika's husband Gustav, who accepted Uta as his child. Blood samples from family members were taken and DNA extracted. A panel of 16 short tandem repeat (STR) loci were amplified and separated by capillary electrophoresis and the likelihoods calculated using the MLINK software. The combined genotypes yielded a cumulative likelihood ratio of over 200,000 against paternity of Gustav H. This case serves to illustrate the utility of STR profiles for complex deficiency kinship analysis.