A mixed DNA profile controversy revisited

Semaan et al. (J Forensic Res, 2020, 11, 453) discuss a mock case “where eight different individuals [P₁ through P₈] could not be excluded in a mixed DNA analysis. Even though … expert DNA mixture analysis software was used.” Two of these are the true donors. The LRs reported are incorrect due to the incorrect entry of propositions into LRmix Studio. This forced the software to account for most of the alleles as drop-in, resulting in LRs 60–70 orders of magnitude larger than expected. P₁, P₂, P₄, P₅, and P₈ can be manually excluded using peak heights. This has relevance when using LRmix which does not use peak heights. We extend the work using the same two reference genotypes who were the true contributors as Semaan et al. (J Forensic Res, 2020, 11, 453). We simulate three two-donor mixtures with peak heights using these two genotypes and analyze using STRmix?. For the simulated 1:1 mixture, one of the non-donors’ LRs supported him being a contributor when no conditioning was used. When considered in combination with any other potential donors (i.e., with conditioning), this non-donor was correctly eliminated. For the 3:1 mixture, all results correctly supported that the non-donors were not contributors. The low-template 4:1 mixture LRs with no conditioning showed support for all eight profiles as donors. However, the results from pair-wise conditioning showed that only the two ground truth donors had LRs supporting that they were contributors to the mixture. We recommend the use of peak heights and conditioning profiles, as this allows better sensitivity and specificity even when the persons share many alleles.     

Improved Area of Origin Estimation for Bloodstain Pattern Analysis Using 3D Scanning

An important component of crime scene reconstruction is bloodstain pattern analysis (BPA). Where BPA concerns impact patterns, estimating the area of origin is critical information for scene reconstruction. Traditionally, this is achieved by measuring individual bloodstains and performing trigonometric calculations; however, 3D scanning has been proposed as a viable alternative for overcoming logistical and practical concerns with the manual method. Therefore, this project aimed to establish whether the FARO Focus 3D scanner and FARO Zone 3D software can improve the accuracy of area of origin estimates relative to the manual method. We created a series of eight bloodstain impact patterns and performed paired analysis using the two methods to estimate areas of origin for each pattern. Our data suggested that FARO-derived estimates were generally more accurate than using the manual method. FARO-estimated heights of origin areas were generally closer to the true distance. Both methods underestimated the distance from the wall for most patterns originating 150mm or greater from the wall, but overestimated distances for patterns originating closer to the wall. The degree to which distances were underestimated increased significantly the further the blood source was from the wall and was greater for FARO-derived estimates. The results of this research contribute to the validation of these instruments for operational implementation for BPA and should be considered alongside the practical benefits of 3D scanning relative to manual methods. Further, 3D scanning can provide reliable BPA reconstruction documentation for technical review and court presentation.     

Contesting Professionalism: Legal Aid and Nonlawyers in England and Wales

Professions are granted a form of cartel that enables them to charge more than would arise in a free market on the assumption that they provide better quality and are more trustworthy than free-market actors would be. The theoretical assumption that lawyers are more competent than nonlawyers has given rise to significant formal protections for professions in many jurisdictions. Two testable propositions arise from this theory: (1) lawyers cost more, but (2) they deliver higher quality. It is a testing of these twin propositions that is the subject of this article, with well-triangulated data and a deeper understanding of the theoretical differences between lawyers and nonlawyers.     

Correlates of Mortality in a U.S. Cohort of Youth, 1980–98: Implications for Social Justice

This paper reports results of a study based on a nationally representative sample of U.S. youth (N = 11,549) that asked two questions: (1) How does family structure affect the likelihood of adolescent death beyond that of race/ethnicity, sex, socioeconomic status, personal behavior, and other structural factors and (2) under what conditions might appeals for social justice be warranted for relative mortality statuses and for absolute gains in mortality? The study found that marital instability increases the likelihood of dying when controlling for a variety of other factors including class, race/ethnicity, sex, and unemployment rate in area of residence. The author argues that this finding lends support to social justice arguments to redistribute resources in such a way as to ensure the likelihood of absolute gains in mortality. The study also found, however, that race/ethnicity/sex also accounted for the likelihood of dying independently of family structure when controlling for socioeconomic and other factors. The author argues that this finding lends support to social justice arguments to redistribute resources on the basis of relative mortality statuses.     

PUNCHING THE PARENTING TIME CLOCK: THE APPROXIMATION RULE,SOCIAL SCIENCE,AND THE BASEBALL BAT KIDS*

The American Law Institute proposes that in contested physical custody cases the court should allocate to each parent a proportion of the child's time that approximates the proportion of time each has spent performing caretaking functions in the past. Examined through the lens of child development research, the approximation rule is unlikely to improve on the best interests standard. It is difficult to apply; is perceived as gender‐biased; creates a new focus for disputing parents; renders a poor estimate of parents’ contributions to their child's best interests; overlooks parents’ intangible, yet significant, contributions to their child's well‐being; and miscalculates the essence of how a child experiences the family. A preferable alternative is a better defined, contemporary best interests standard that accommodates new knowledge and reforms that encourage nonadversarial, individualized resolutions of custody disputes.