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Determining the Proper Evidentiary Basis for an Expert Opinion: What Do Experts Need to Know and When Do They Know Too Much?

NCJ Number
310962
Date Published
2017
Abstract

What does an expert need to know when making judgments and offering opinions that someone else will use to make a decision? When does the expert need to know as much as the decision maker about the matter at issue, and when is it better that the expert be blind to some of the facts that the decision maker will consider? If blinding procedures are warranted, what facts should be kept from the expert? Questions of this kind arise in a variety of domains, including criminal justice, intelligence analysis, and clinical medicine. This chapter offers a conceptual analysis of these questions using Bayesian influence diagrams. It provides formal criteria for assessing the relevance of a given fact to an expert's task and demonstrates that the probative value of expert evidence (its value to the decision maker) can be undermined if the expert is influenced by task-irrelevant information. The chapter provides a helpful framework for designing context management procedures to address the problem of contextual bias in domains such as forensic science, clinical medicine, and intelligence analysis.

(Publisher abstract provided.)

Date Published: January 1, 2017