title: Using continuous DNA interpretation methods to revisit likelihood ratio behaviour.
abstract: Continuous DNA interpretation systems make use of more information from DNA profiles than analysts have previously been able to with binary, threshold based systems. With these new continuous DNA interpretation systems and a new, more powerful, DNA profiling kit (GlobalFiler) there is an opportunity to re-examine the behaviour of a commonly used statistic in forensic science, the likelihood ratio (LR). The theoretical behaviour of the LR has been known for some time, although in many instances the behaviour has not been able to be thoroughly demonstrated due to limitations of the biological and mathematical models being used. In this paper the effects of profile complexity, replicate amplifications, assuming contributors, adding incorrect information, and adding irrelevant information to the calculation of the LR are explored. The empirical results are compared to theoretical expectations and explained. The work finishes with the results being used to dispel common misconceptions around reliability, accuracy, informativeness and reproducibility.
authors.affiliation: Forensic Science South Australia, 21 Divett Place, Adelaide, SA 5000, Australia; School of Biological Sciences, Flinders University, GPO Box 2100 Adelaide SA 5001, Australia. Electronic address: Duncan.Taylor@sa.gov.au.
authors.forename: Duncan
authors.initials: D
authors.lastname: Taylor
mesh_terms: D004247:DNA / Q000235:genetics*; D053803:Forensic Genetics; D006801:Humans; D016013:Likelihood Functions
chemical_list: D004247:DNA
keywords: Assumed contributors; DNA profile interpretation; Likelihood ratio; Mixtures; Reliability; STRmix