New York Federal Criminal Practice Blog
September 10, 2007

Revelation of Defendant's Prior Criminal Record Tips Balance in Favor of Conviction in Close Cases

Courtesy of Hofstra law professor Eric Freedman on the Federal Trials Listserve, I learned of this fascinating article by two Cornell law professors, Theodore Eisenberg and Valerie Hans: Taking a Stand on Taking the Stand: The Effect of Prior Criminal Record on the Decision to Testify and on Trial Outcomes.Analyzing a unique set of data collected from 300 criminal trials in 4 large counties, including Bronx Co., New York, which included a quantitative measure of the jurors' and judges' overall estimate of the strength of the evidence, the authors conclude that statistically significant associations exist (1) between the existence of a criminal record and the decision to testify at trial, (2) between the defendant testifying at trial and the jury learning about the defendant's prior record, and (3) in cases with weak evidence, between the jury learning of a criminal record and conviction. Essentially, in cases where the evidence against the defendants is strong, learning of criminal records is not strongly associated with conviction rates. In cases where the evidence would not normally support conviction, however, juries appear to rely on criminal records to convict. In fact, "[t]he effect in otherwise weak cases is substantial and can increase the probability of conviction to over 50 percent, when the probability of conviction in similar cases without criminal records is less than 20 percent." The authors conclude that "[t]he enhanced conviction probability that prior record evidence supplies in close cases may well contribute to erroneous convictions."

While most defense lawyers know this intuitively, it is always helpful to have one's instincts confirmed by empirical evidence. More importantly, this research arms a defense lawyer with persuasive data to advise a client with a criminal record against testifying in a close case, or to persuade a judge in a pretrial motion to preclude the government from cross-examining the defendant about his/her record.

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