Americans may not join bowling leagues anymore, but one pillar of civil life still is quite strong: the jury. Every day, in every community across the nation, average citizens gather in courthouses to make decisions about their fellow citizens in civil and criminal proceedings. But do juries work? Do they make decisions that are better than judges could make solely? Is the institution thriving or does it need to be improved?

Cornell professor of law Valerie Hans addresses these questions and many more in her groundbreaking new survey of the field of jury studies, "American Juries: The Verdict." She wrote the book with her longtime collaborator, Neil Vidmar, professor of law and psychology at Duke University.

"American Juries: The Verdict" surveys the 30-year-old field of jury studies. The authors summarize many studies and comment on jury reforms. In general, they find that the jury system is healthy.

"By and large," says Hans, "juries work very well for the system. They have a lot of purposes and functions that go beyond the finding of facts in any one particular case." She notes that while juries may look like a wild card in the justice system, studies actually show they are usually predictable. "Quite a bit of their decision is determined by the case that the lawyers present to them. One of the key points of the book is that what seems like a wild card, in fact, follows rules. The strength of the evidence in the case will give you a good sense about what a jury is going to do."

The one exception, Hans notes, is in capital cases. It's not clear that juries are the best way to decide to impose the death penalty, because of an inherent flaw in the system. People who oppose the death penalty are not allowed on capital juries. "The strength of the jury is a diversity in decision making, which makes for a very robust process," says Hans. "And you're less likely to have that in a capital case because of the selection process." Despite the fact that juries don't function well for capital cases, Hans and Vidmar still advocate using them, as they see no other alternative.

Trained as a social scientist, Hans has carried out extensive research and written widely about social science and the law. She joined the Cornell faculty in 2006, and previously, she published "The Jury System: Contemporary Scholarship" (2006), "Business on Trial: The Civil Jury and Corporate Responsibility" (2000) and "Judging the Jury" (1986, co-authored with Vidmar).

This article is adapted from the spring 2008 issue of the Cornell Law Forum.