The ability of prospective jurors to estimate the accuracy of eyewitness identifications.

This study investigated whether people's “common knowledge” is sufficient to enable them to accurately assess the validity of evidence based upon an eyewitness report. Prospective jurors were provided with descriptions of actual research studies on eyewitness identification and asked to predict the research results. A sample of registered voters, selected to represent the court's lists of prospective jury members, was presented with scenarios derived from the method sections of previously conducted empirical studies of eyewitness identification involving target-present lineups. Respondents' estimates of the hit rates in the three target-present situations were significantly greater than the actual hit rates in each of the three cases. The mean percentage of respondents who overestimated the hit rates, averaged across the three cases, was 83.7%. The results indicate that awareness of the unreliability of eyewitness evidence does not appear to be part of the “common knowledge” of prospective jury members. These data can be seen as refuting the claim made by some courts that expert testimony about eyewitness evidence would not tell the jury members anything they did not already know.