A study conducted by a Northwestern professor has found a way to measure the rate of error in the verdict decisions made by judges and juries during trials.The study found that one out of eight juries made the wrong decision in a set of court cases being analyzed, said Bruce Spencer, the author of the study and a Statistics professor at NU. Spencer utilized a study conducted by the National Center for State Courts that included 271 criminal cases tried in state courts in four different cities. “The big finding is that you can do the study,” Spencer said. Only in a handful of cases where DNA evidence is later retrieved or when the true criminal confesses can it be known for certain whether juries gave the correct verdict or not, he said. The study conducted offers another way to find out the probability of how accurate the verdict is, he said.Spencer cautioned that the numerical findings only pertained to the set of data he studied and that they could not be generalized for all other cases. The importance of the study is that it provides information for people who want to study the justice system, Spencer said.”As a society, we like to know how well our schools are doing, and our hospitals,” Spencer said. “We should also know how well our courts are doing.”To conduct the study, Spencer, a Faculty Fellow at the Institute for Policy Research, compared the decisions of judges and jurors on the same cases. Judges were asked to report their decisions before the jurors gave their decision.It could not be assumed that the judge was any more correct than the jury, Spencer said. John Heinz, a law professor at the Northwestern School of Law, recommended a set of data for Spencer to study. Spencer’s study is an innovative way to answer the question of accurate convictions in court cases, Heinz said.”You wouldn’t think that without knowing (the real answer) you could estimate the error rate, but Bruce has figured out a way to do it,” Heinz said.The study, funded by the Institute for Policy Research, will be published in the July issue of Journal of Empirical Legal Studies.