Perjury, faulty eyewitness identification and prosecutorial misconduct are the leading reasons for wrongful convictions, according to the first national registry of exonerations compiled by university researchers.
The database, assembled in a collaboration by the University of Michigan and Northwestern University, has identified 873 faulty convictions in the past 23 years that have been recognized by prosecutors, judges or governors.
The registry's founders say the numbers, which do not include many cases in which innocent suspects plead guilty to avoid the risk of more serious punishments or cases that have been dismissed because of legal error without new evidence of innocence, represent only a fraction of the problem in the nation's criminal justice system.
"What this shows is that the criminal justice system makes mistakes, and they are more common than people think," said University of Michigan law professor Samuel Gross, the registry's editor. "It is not the rule, but we won't learn to get better unless we pay attention to these cases."