A Statistical Basis for Reporting Strength of Evidence as Pool Reduction

Abstract

This article establishes a statistical basis for an evidence-reporting strategy that interprets strength of evidence in terms of a reduction in the size of a pool of relevant conceptual objects. The strategy is motivated by debates in forensic science, wherein the pool would consist of sources of forensic material. An advantage of using the pool-reduction strategy is that it highlights uncertainty that cannot be resolved by empirical considerations. It is shown mathematically to reflect a nonstandard formulation of a Bayes factor, and to extend for use in problems of general quantitative inference. A number of conventions are proposed for full effectiveness of the strategy’s implementation in practice.