Koehler, J. J. (1992). Probabilities in the Courtroom: An Evaluation of the Objections and Policies. In Kagehiro, D. K., & Laufer, W. S. (Eds.). Handbook of Psychology and Law. p. 167-184. NY:Springer-Verlag.

ABSTRACT

In short, objections to probabilistic evidence and arguments have been made at both the level of accuracy and policy. It is important to clearly distinguish between these two types of objections, which have a way of becoming merged and confused in discussion (Koehler, 1991). If probabilistic evidence impedes accurate fact-finding, then it should be excluded at trial. But in the absence of clear and convincing evidence that this is the case, the expected benefits of probability evidence must be weighed against the various policy objections to determine how, if at all, this evidence should be employed.

This chapter examines the concerns and policies surrounding the use of probability evidence. Sections I and II examine a series of accuracy and policy arguments that have been leveled against probabilistic evidence and arguments at trial. A critical examination of these arguments finds them to be unpersuasive at best and erroneous at worst. Section III identifies several practical problems associated with implementing probabilistic methodologies at trial which limit their use. Section IV explores the reception probabilistic evidence and methods have received in the courts, while section V considers ways to improve responses to this evidence through education and further research.