title: The factor of 10 in forensic DNA match probabilities.
abstract: An update was performed of the classic experiments that led to the view that profile probability assignments are usually within a factor of 10 of each other. The data used in this study consist of 15 Identifiler loci collected from a wide range of forensic populations. Following Budowle et al. [1], the terms cognate and non-cognate are used. The cognate database is the database from which the profiles are simulated. The profile probability assignment was usually larger in the cognate database. In 44%-65% of the cases, the profile probability for 15 loci in the non-cognate database was within a factor of 10 of the profile probability in the cognate database. This proportion was between 60% and 80% when the FBI and NIST data were used as the non-cognate databases. A second experiment compared the match probability assignment using a generalised database and recommendation 4.2 from NRC II (the 4.2 assignment) with a proxy for the matching proportion developed using subpopulation allele frequencies and the product rule. The findings support that the 4.2 assignment has a large conservative bias. These results are in agreement with previous research results.
authors.affiliation: National Institute of Standards and Technology, 100 Bureau Drive, MS 8980 Gaithersburg, MD 20899, USA. Electronic address: simone.gittelson@nist.gov.
authors.forename: Simone
authors.initials: S
authors.lastname: Gittelson
authors.affiliation: DNA Support Unit, Federal Bureau of Investigation Laboratory, 2501 Investigation Parkway, Quantico, VA 22135, USA.
authors.forename: Tamyra R
authors.initials: TR
authors.lastname: Moretti
authors.affiliation: DNA Support Unit, Federal Bureau of Investigation Laboratory, 2501 Investigation Parkway, Quantico, VA 22135, USA.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Onorato
authors.affiliation: Center for Human Identification, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107, USA; Center of Excellence in Genomic Medicine Research (CEGMR), King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Bruce
authors.initials: B
authors.lastname: Budowle
authors.affiliation: Department of Biostatistics, University of Washington, Seattle, WA 98195, USA.
authors.forename: Bruce S
authors.initials: BS
authors.lastname: Weir
authors.affiliation: Department of Biostatistics, University of Washington, Seattle, WA 98195, USA; ESR Ltd, Private Bag 92021, Auckland 1142, New Zealand.
authors.forename: John
authors.initials: J
authors.lastname: Buckleton
mesh_terms: D016172:DNA Fingerprinting; D030561:Databases, Nucleic Acid; D005787:Gene Frequency; D006801:Humans; D015233:Models, Statistical; D011336:Probability; D044469:Racial Groups / Q000235:genetics
keywords: Allele frequency; Database; Subpopulations; Weight of evidence