Graphics convey numerical information very efficiently, but rely on a different set of mental processes than tabular displays. Here, we present a study relating demographic characteristics and visual skills to perception of graphical lineups. We conclude that lineups are essentially a classification test in a visual domain, and that performance on the lineup protocol is associated with general aptitude, rather than specific tasks such as card rotation and spatial manipulation. We also examine the possibility that specific graphical tasks may be associated with certain visual skills and conclude that more research is necessary to understand which visual skills are required in order to understand certain plot types.

The 2009 National Academy of Sciences report found pattern‐evidence disciplines to be rife with subjectivity. In the decade since, machine learning methods have been developed to try to address that issue. By Alicia Carriquiry, Heike Hofmann, Xiao Hui Tai and Susan VanderPlas.

In the past decade, and in response to the recommendations set forth by the National Research Council Committee on Identifying the Needs of the Forensic Sciences Community (2009), scientists have conducted several black-box studies that attempt to estimate the error rates of firearm examiners. Most of these studies have resulted in vanishingly small error rates, and at least one of them (D. P. Baldwin, S. J. Bajic, M. Morris, and D. Zamzow. A Study of False-Positive and False-Negative Error Rates in Cartridge Case Comparisons. Technical report, Ames Lab IA, Performing, Fort Belvoir, VA, April 2014.) was cited by the President’s Council of Advisors in Science and Technology (PCAST) during the Obama administration, as an example of a well-designed experiment. What has received little attention, however, is the actual calculation of error rates and in particular, the effect of inconclusive findings on those error estimates. The treatment of inconclusives in the assessment of errors has far-reaching implications in the legal system. Here, we revisit several black-box studies in the area of firearms examination, investigating their treatment of inconclusive results. It is clear that there are stark differences in the rate of inconclusive results in regions with different norms for training and reporting conclusions. More surprisingly, the rate of inconclusive decisions for materials from different sources is notably higher than the rate of inconclusive decisions for same-source materials in some regions. To mitigate the effects of this difference we propose a unifying approach to the calculation of error rates that is directly applicable in forensic laboratories and in legal settings.

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