title: A Practical Guide for the Formulation of Propositions in the Bayesian Approach to DNA Evidence Interpretation in an Adversarial Environment.
abstract: The interpretation of complex DNA profiles is facilitated by a Bayesian approach. This approach requires the development of a pair of propositions: one aligned to the prosecution case and one to the defense case. This note explores the issue of proposition setting in an adversarial environment by a series of examples. A set of guidelines generalize how to formulate propositions when there is a single person of interest and when there are multiple individuals of interest. Additional explanations cover how to handle multiple defense propositions, relatives, and the transition from subsource level to activity level propositions. The propositions depend on case information and the allegations of each of the parties. The prosecution proposition is usually known. The authors suggest that a sensible proposition is selected for the defense that is consistent with their stance, if available, and consistent with a realistic defense if their position is not known.
authors.affiliation: Department of Biostatistics, University of Washington, Seattle, WA, 98195.
authors.forename: Simone
authors.initials: S
authors.lastname: Gittelson
authors.affiliation: U.S. Army Criminal Investigation Laboratory, 4930 North 31st Street, Forest Park, GA, 30297.
authors.forename: Tim
authors.initials: T
authors.lastname: Kalafut
authors.affiliation: California Department of Justice, Jan Bashinski DNA Laboratory, Richmond, CA, 94804.
authors.forename: Steven
authors.initials: S
authors.lastname: Myers
authors.affiliation: Forensic Science South Australia, 21 Divett Place, Adelaide, SA, 5000, Australia.
authors.forename: Duncan
authors.initials: D
authors.lastname: Taylor
authors.affiliation: School of Criminal Justice, University of Lausanne, 1015, Lausanne, Switzerland.|Foundation for Continuing Education UNIL-EPFL, EPFL Innovation Park, 1015, Lausanne, Switzerland.
authors.forename: Tacha
authors.initials: T
authors.lastname: Hicks
authors.affiliation: School of Criminal Justice, University of Lausanne, 1015, Lausanne, Switzerland.
authors.forename: Franco
authors.initials: F
authors.lastname: Taroni
authors.affiliation: Principal Forensic Services Ltd, 34 Southborough Road, Bromley, BR1 2EB, UK.
authors.forename: Ian W
authors.initials: IW
authors.lastname: Evett
authors.affiliation: ESR Ltd, Private Bag 92021, Auckland, 1142, New Zealand.
authors.forename: Jo-Anne
authors.initials: JA
authors.lastname: Bright
authors.affiliation: ESR Ltd, Private Bag 92021, Auckland, 1142, New Zealand.
authors.forename: John
authors.initials: J
authors.lastname: Buckleton
mesh_terms: D016172:DNA Fingerprinting; D005554:Forensic Medicine / Q000331:legislation & jurisprudence*; D006801:Humans; D016013:Likelihood Functions
keywords: Bayesian approach; DNA mixtures; forensic DNA; forensic science; likelihood ratio; propositions