A comment on the PCAST report: Skip the “match”/“non-match” stage

Geoffrey Stewart Morrison, David H. Kaye, David J. Balding, Duncan Taylor, Philip Dawid, Colin G.G. Aitken, Simone Gittelson, Grzegorz Zadora, Bernard Robertson, Sheila Willis, Susan Pope, Martin Neil, Kristy A. Martire, Amanda Hepler, Richard D. Gill, Allan Jamieson, Jacob de Zoete, R. Brent Ostrum, Kiel Caliebe

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    24 Citations (Scopus)

    Abstract

    This letter comments on the report “Forensic science in criminal courts: Ensuring scientific validity of feature-comparison methods” recently released by the President's Council of Advisors on Science and Technology (PCAST). The report advocates a procedure for evaluation of forensic evidence that is a two-stage procedure in which the first stage is “match”/“non-match” and the second stage is empirical assessment of sensitivity (correct acceptance) and false alarm (false acceptance) rates. Almost always, quantitative data from feature-comparison methods are continuously-valued and have within-source variability. We explain why a two-stage procedure is not appropriate for this type of data, and recommend use of statistical procedures which are appropriate.

    Original languageEnglish
    Pages (from-to)e7-e9
    Number of pages3
    JournalForensic Science International
    Volume272
    DOIs
    Publication statusPublished - 1 Mar 2017

    Keywords

    • False alarm
    • Forensic statistics
    • Likelihood ratio
    • Match/non-match
    • PCAST report
    • Sensitivity

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