04/17/2012 01:36 pm ET Updated Dec 06, 2017

All-White Jury Pools In Florida Convict Blacks 15 Percent More Often Than Whites, Study Finds

In Florida, all-white jury pools found blacks accused of crimes guilty 16 percent more often than they did with white defendants according to a new study by researches at Duke University.

The study also found that the disparity in guilty verdicts essentially vanished with the presence of just one black juror in the pool of jurors.

"I think this is really the first strong and convincing evidence that the racial composition of a jury actually has a big effect on trial outcomes," Patrick Bayer, the chairman of the economics department at Duke and the study's senior author, said in a video about the report. "Our Sixth Amendment right to a trial [with] a jury of our peers is a bedrock of the criminal justice system in the U.S., and yet despite the importance of that right there's been actually very little systematic analysis of how the composition of juries actually affects trial outcomes and how the rules we have in place actually affect those outcomes."

The researchers looked at data from about 700 trials in Sarasota and Lake counties in Florida over a 10-year period, and then looked at the race of the defendant, the charges against him or her, and the case's outcome.

"We focus on what happened to the conviction rates in the trials where there are no blacks in the jury pool," he said. "Of course there can't be any black members of the jury then."

According to the study, a jury pool — which is usually about 27 people — that has no black members convicted black defendants 81 percent of the time and white defendants 66 percent of the time, a 15-point difference.

But adding just one black juror drove the convictions of blacks down to 71 percent, a shade lower than the 71 percent conviction rate for white defendants with at least one black potential juror in the pool.

"So there's basically a 17-percentage point change in conviction rates just based on this random change, day to day, on who's called for jury duty," Bayer said.