The impact of case characteristics and prior jury experience on jury verdicts.

Werner, C. M., Strube, M. J., Cole, A. M., & Kagehiro, D. K. (1985). The impact of case characteristics and prior jury experience on jury verdicts. Journal of Applied Social Psychology, 15, 409-427.

An archival analysis of records from 206 criminal cases was used to evaluate the impact of personal and situational factors on jury verdicts. In particular, we evaluated whether repeated jury service produced bias in jurors that was sufficient to affect jury decisions. A variety of case characteristics and indices of prior jury experience was examined for their relative impact on trial outcomes. Several of the case characteristics were related to verdicts, but the personal characteristics were not. Although more than half of the juries contained experienced jurors, juror experience had little influence on verdicts in either major or subsidiary analyses. However, there was a slight tendency for small juries with large proportions of experienced jurors to convict. This result is consistent with data from Kentucky; a meta-analysis across the two data sets indicates that it is a reliable finding. The results have implications for the determination of jury size. We suggest that future research examine the possibility that increasing jury size may reduce the influence of an individual’s bias by providing a balance of other jurors with no or offsetting biases.

Number and proportion of experienced jurors unrelated to jury verdicts (r = .08 for both), but proportion of experienced jurors moderately related to proportion of count convictions (r = .24). Number of defense witnesses, jury size, and severity of primary charge best predictors of acquittal (all positively related);
r<2> = .11.

http://onlinelibrary.wiley.com/doi/10.1111/j.1559-1816.1985.tb02262.x/abstract