Evaluating forensic biology results given source level propositions. (March 2016)

• Record Type: Journal Article
• Authors: Taylor, Duncan; Abarno, Damien; Hicks, Tacha; Champod, Christophe
• Is Part Of: Forensic science international. Volume 21(2016:Mar.)
• Page Start: 54
• Page End: 67
• Publication Date: 2016-03
• Subjects: Source level propositions -- Bayesian networks -- Likelihood ratio -- Hierarchy of propositions -- STRmix -- Body fluid -- Presumptive tests; Forensic genetics -- Periodicals; Génétique légale -- Périodiques; Forensic genetics; Electronic journals; Periodicals; 614.1
• DOI: 10.1016/j.fsigen.2015.11.009
• Languages: English
• ISSNs: 1872-4973

Abstract

Abstract: The evaluation of forensic evidence can occur at any level within the hierarchy of propositions depending on the question being asked and the amount and type of information that is taken into account within the evaluation. Commonly DNA evidence is reported given propositions that deal with the sub-source level in the hierarchy, which deals only with the possibility that a nominated individual is a source of DNA in a trace (or contributor to the DNA in the case of a mixed DNA trace). We explore the use of information obtained from examinations, presumptive and discriminating tests for body fluids, DNA concentrations and some case circumstances within a Bayesian network in order to provide assistance to the Courts that have to consider propositions at source level. We use a scenario in which the presence of blood is of interest as an exemplar and consider how DNA profiling results and the potential for laboratory error can be taken into account. We finish with examples of how the results of these reports could be presented in court using either numerical values or verbal descriptions of the results.