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.     

Book Review International Environmental Negotiations: The Current State of Empirical and Analytic Study

Negotiation Journal -     

Are disturbed and normal adolescents equally competent to make decisions about mental health treatments?

This study uses a structured vignette procedure to assess competency to make treatment decisions in two groups of adolescents, one at risk for institutional placement and the other a matched community sample. Scores on Factual Understanding (the ability to recall facts), Inferential Understanding (the ability to make inferences about those facts), and Reasoning (the ability to weigh risks and benefits of various treatment options and to make choices based on that reasoning) were compared. Results showed that while at-risk adolescents and their community, counterparts did not differ in their factual and inferential understanding abilities, the at-risk adolescents did significantly less well than the community adolescents in reasoning. This difference could not be fully explained by differences in verbal IQ. Girls, no matter what their risk status, scored higher than boys on the Reasoning scale. Implications for legal policies concerning adolescents are discussed.