P-Values should not be used for evaluating the strength of DNA evidence. (May 2015)

• Record Type: Journal Article
• Authors: Kruijver, Maarten; Meester, Ronald; Slooten, Klaas
• Is Part Of: Forensic science international. Volume 16(2015:May)
• Page Start: 226
• Page End: 231
• Publication Date: 2015-05
• Subjects: Likelihood ratios -- p-Values -- Weight of evidence -- Mixtures -- Kinship; Forensic genetics -- Periodicals; Génétique légale -- Périodiques; Forensic genetics; Electronic journals; Periodicals; 614.1
• DOI: 10.1016/j.fsigen.2015.01.005
• Languages: English
• ISSNs: 1872-4973

Abstract

Abstract : Highlights: p -Values have recently been proposed for interpreting DNA evidence instead of likelihood ratios. p -Values do not relate to the strength of DNA evidence. Evaluating DNA evidence using p -values can be problematic and misleading. Examples from mixture interpretation and kinship testing demonstrate the problems associated with p -values. Abstract: Recently, p -values have been suggested to explain the strength of a likelihood ratio that evaluates DNA evidence. It has been argued that likelihood ratios would be difficult to explain in court and that p -values would offer an alternative that is easily explained. In this article, we argue that p -values should not be used in this context. p -Values do not directly relate to the strength of the evidence. The likelihood ratio measures the strength of the evidence, while the p -value measures how rare it is to find evidence that is equally strong or stronger, which is something fundamentally different. In addition, a p -value is not always unambiguous. To illustrate our arguments, we present several examples from forensic genetics.