title: Application of random match probability calculations to mixed STR profiles.
abstract: Mixed DNA profiles are being encountered more frequently as laboratories analyze increasing amounts of touch evidence. If it is determined that an individual could be a possible contributor to the mixture, it is necessary to perform a statistical analysis to allow an assignment of weight to the evidence. Currently, the combined probability of inclusion (CPI) and the likelihood ratio (LR) are the most commonly used methods to perform the statistical analysis. A third method, random match probability (RMP), is available. This article compares the advantages and disadvantages of the CPI and LR methods to the RMP method. We demonstrate that although the LR method is still considered the most powerful of the binary methods, the RMP and LR methods make similar use of the observed data such as peak height, assumed number of contributors, and known contributors where the CPI calculation tends to waste information and be less informative.
authors: U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives Laboratory, National Laboratory Center, 6000 Ammendale Road, Ammendale, MD, 20705.
authors: Todd
authors: T
authors: Bille
authors: Jo-Anne
authors: JA
authors: Bright
authors: John
authors: J
authors: Buckleton
mesh_terms: D016172:DNA Fingerprinting; D006801:Humans; D016013:Likelihood Functions; D018895:Microsatellite Repeats; D008957:Models, Genetic; D015233:Models, Statistical; D011336:Probability
keywords: forensic DNA interpretation; forensic science; low template; mixtures; random match probability; short tandem repeat