Some Reservations About Likelihood Ratios (and Some Other Aspects of Forensic Bayesianism)

Abstract:     
This paper is an expansion of a talk given at the 8th International Conference on Forensic Inference and Statistics in Seattle, July 19, 2011. The focus of the paper is the application of modern Bayesianism in the context of forensic science, as advocated by many in England and Europe. The paper reviews the many aspects of modern Bayesianism that extend well beyond the analytic truth of Bayes’s Theorem, and focuses, among other things, on the limits of what can be accomplished by the invocation of “subjective” probabilities. In a sense, all probabilities are subjective, since they are all mind dependent. However, the important issue in forensic contexts, as in others, is not the subjective nature of invoked probabilities, but the characteristics of the belief warrant to be required for them in different decisional contexts. In the end, I find myself drawn to forensic Bayesianism, but not fully converted.

Number of Pages in PDF File: 18

Keywords: evidence, expert evidence, scientific evidence, Bayesianism, Bayes's Theorem, statistics

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