A fair trial is harder to come by than you might think. A few years ago, we wrote about a paper (ungated version here) by Shamena Anwar, Patrick Bayer, and Randi Hjalmarsson which found that “all-white juries acquit whites more often and are less favorable to black versus white defendants when compared to juries with at least one black member.”
Now, a new working paper by the same trio has more bad news:
[P]rosecutors are more likely to use their peremptory challenges to exclude younger members of the jury pool, while defense attorneys exclude older potential jurors. Having established that age has an important role in jury selection, the paper employs a research design that isolates the effect of the random variation in the age composition of the pool of eligible jurors called for jury duty to examine the causal impact of age on trial outcomes. Consistent with the jury selection patterns, the empirical evidence implies that older jurors are indeed more likely to convict.
The authors go on to discuss one possible solution: removing age-based peremptory challenges. “However, removing age-based peremptory challenges would also increase the variance of the average age of the seated jury – by about 13 percent in our sample,” they write. ”And, because juror age has a causal effect on trial outcomes, this would, in turn, increase the variation in the outcomes in trials with comparable cases.” The authors suggest increasing jury size to balance out the effects of removing age-based challenges: “[I]ncreasing the jury size in Florida from six to eight would reduce the variance of the age of seated juries enough to offset the increased variance due to the random seating of jurors.”