Weight of Evidence

Abstract

This chapter analyzes and operationalizes a concept of “weight” as denoting the relative degree to which evidence has been developed on the basis of which to determine disputed claims. This concept was coined by John Maynard Keynes and later applied in the context of judicial proof by a number of scholars. The author distinguishes weight from the degree to which evidence favors one side over the other, and then assays the different ways this concept of weight can be operationalized. He identifies the strengths and weaknesses of various theories, and advocates a conception of weight that emphasizes its connection to fundamental policy choices about the importance of accuracy in litigation and, perhaps, the allocation of the risk of error. He argues that a common failure to appreciate the differences between ordinary decision-making under uncertainty and formal adjudication is responsible for confusion about the role of weight in the latter.