Faculty Journal Articles and Book Chapters

An Aggregation Theory of Character Evidence

ORCID (Links to author’s additional scholarship at ORCID.org)



Courts frequently depart from Federal Rule of Evidence 404, which prohibits evidence of a person’s prior acts to prove that the person acted according to a certain character. This leads to verdicts that are unpredictable and based on behavior not at issue in a case. I develop a theory of aggregation evidence, a new concept that draws on principles of estimation and data aggregation in statistics and ties together evidence from a broad range of contexts. I apply this theory to analyze the effects of character evidence on accuracy and to understand why and when courts depart from the rule against character evidence. I show that a type of character evidence that I call objective-chance evidence stands apart from other forms of character evidence in its ability to improve accuracy. I then argue that a formal exception for this type of evidence may lead to a more coherent rule.

Publication Title

The Journal of Legal Studies

Document Type



character evidence, Rule 404, Federal Rules of Evidence, FRE, doctrine of chances, prior-acts evidence, other-acts evidence, propensity evidence, doctrine of objective chances, judgment variability, unpredictability, accuracy, bias-variance tradeoff, shrinkage estimation, hierarchical model



Digital Object Identifier (DOI)