More than 2,000 inmates and ex-cons have been exonerated since 1989, according to the database that aims to track all wrongful convictions in the United States. More than 100 had been sentenced to death.
"This is a beginning," said University of Michigan Law School professor Samuel Gross, one of the database's creators. "One of my great hopes is that this will lead us to learn more about exonerations."
The database, which was developed with members of Northwestern University's Center on Wrongful Conviction, focused on 873 individual cases. The researchers also identified 13 major police scandals that falsely netted 1,170 other people, although these are not included in the database because they are the results of a collective exoneration based on problems in individual agencies.
Among the findings by the database researchers:
Perjury and false accusations are the most common causes of a bogus conviction, accounting for 51 percent of the cases included in the database;
Men make up 93 percent of the exonerated defendants;
African Americans represent 50 percent of the names on the database; whites make up 38 percent. Latinos account for 11 percent, and Native Americans and Asians make up 2 percent;
The most common crime on the list is murder, representing 48 percent of the exonerations. Sexual assaults are the second most common at 35 percent. There's a steep drop-off to other crimes, with robberies equaling 5 percent, while drug, white collar and non-violent crimes amount to 7 percent;
There have been 101 death-row inmates freed.
"The most important goal of the [criminal justice] system is accuracy," Gross told HuffPost. "Getting the right person and not getting the wrong person are obviously the most important goals. The only way to get those are to learn how we made our mistakes."
One reason Gross and his colleagues believe they're just scratching the surface there are geographical clusters that they found, like Chicago's Cook County -- which leads the country with 78 exonerations. There are other densely populated counties, like Fairfax, Va., that don't have any exonerations.
Areas with high numbers of freed men and women aren't necessarily more prone to police misconduct or overzealous prosecutors, Gross said. "I'm very sympathetic to police officers," he said. "They're overworked and they're right most of the time. But most of the time is not all the time."
Often the work of an aggressive organization like the Northern California Innocence Project in Santa Clara County, which the database shows has had 10 exonerations, can be behind the cases. Nearby Alameda County, where there is no such organization, has no exonerations, Gross said.
A high number of exonerations in certain states also might mean that legal watch groups there are more active and effective.