Statistics and the Fair Administration of Justice
Presented by Hal Stern, University of California, Irvine
March 25, 2020
Time: 12:00 – 1:30 p.m. PT
Host location: Santa Monica
Other locations: Pittsburgh
Abstract: Statistics has emerged as a critical topic in ongoing discussions regarding the use of science to assess forensic evidence. A 2009 National Academies report on forensic science and a subsequent 2016 report by the President’s Council of Advisers on Science and Technology raised questions about the scientific underpinnings for the analysis of a number of types of forensic evidence. Misapplication of forensic science has been identified as a contributing factor in nearly half of 362 cases in which DNA helped exonerate wrongly-convicted individuals. For these reasons there has been an increased focus on evaluating the ways in which evidence is analyzed, interpreted and reported with an eye towards providing more scientifically justified methods. There are three common approaches to the analysis and interpretation of forensic evidence: (1) forensic conclusions as expert opinion; (2) two-stage procedures (determination of similarity of known/questioned items followed by an assessment of significance); (3) likelihood ratios. The first of these, forensic conclusions as expert opinion, has been the standard approach in the pattern comparison disciplines (e.g., fingerprints, firearms, handwriting) but is now being questioned. The logical and statistical issues associated with each of the approaches are discussed in the context of current research.