Practical Guide for the Formulation of Propositions in the Bayesian Approach to DNA Evidence Interpretation in an Adversarial Environment

• NCJ Number: 249398
• Journal: Journal of Forensic Sciences Volume: 61 Issue: 1 Dated: Jan 2016 Pages: 186-195
• Author(s): Simone Gittelson; Tim Kalafut; Steven Myers; Duncan Taylor; Tacha Hicks; Franco Taroni; Ian W. Evett; Jo-Anne Bright; John Buckleton
• Date Published: January 2016
• Length: 10 pages
• Grant Number(s): 2011-DN-BX-K541
• Sponsoring Agency: National Institute of Justice (NIJ)
• Publication Format: Document (Online)
• Publication Type: Report (Technical Assistance); Report (Grant Sponsored); Instructional Material (Programmed)
• Language: English
• Country: United States of America

Annotation

This note explores the issue of proposition setting in an adversarial environment by a series of examples.

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. 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 sub-source 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. (Publisher abstract modified)