Exonerations in the United States, 1989–2012

109 Pages Posted: 26 Jun 2012 Last revised: 12 Jul 2012

See all articles by Samuel R. Gross

Samuel R. Gross

University of Michigan Law School

Michael Shaffer

University of Michigan Law School

Date Written: June 25, 2012


This study presents and analyzes data on the first 873 exonerations reported by the National Registry of Exonerations, exonerationsregistry.org, a new project of the University of Michigan Law School and the Center on Wrongful Convictions at Northwestern University School of Law. The Registry assembles and posts information on exonerations of people who were convicted of serious crimes in the United States.

The database, which includes exonerations from January 1989 through February 2012, is larger and more diverse than any comparable collection. Over 60% of the cases did not involve DNA evidence. Earlier datasets were limited almost entirely to rape and murder cases, but more than 150 of these exonerations were for convictions that did not involve homicide or sexual assault, and more than 100 of the sexual assault exonerations were from child sex abuse convictions.

The study also describes over 1100 additional 'group exonerations' that occurred in the aftermath of 12 scandals around the country in which police officers systematically planted or fabricated evidence to frame defendants for non-existent crimes, usually drug crimes.

The major findings of the study include:

(1) The composition and distribution of the exonerations we know about lead to the inescapable conclusion that they are a small fraction of all false convictions for serious felonies. (Exonerations for lesser felonies and misdemeanors are almost entirely absent from the data.) The known cases also strongly suggest that most exonerations escape notice as well.

(2) The causes of false convictions vary greatly by crime. For homicides, which account for nearly half of all exonerations in the study, the leading cause of error was perjury and other false accusations – usually deliberate false identification of the defendant as the criminal. Homicide exonerations also include a high rate of official misconduct and three-quarters of all false confessions in the study. For adult sexual assault cases, and for the much smaller number of robbery exonerations, the leading cause of error was mistaken witness identifications. Sexual assault exonerations also include a large number of cases with false or misleading forensic evidence. Most child sex abuse exonerations, by contrast, were based on fabricated crimes: the defendants were accused and convicted of crimes that never occurred.

Judging from these data, the conviction of innocent defendants is not a single problem but several distinct problems, depending on the nature of the underlying crime.

Keywords: false convictions, wrongful convictions, exonerations, false confessions, DNA, criminal law, perjury, misidentification

Suggested Citation

Gross, Samuel R. and Shaffer, Michael, Exonerations in the United States, 1989–2012 (June 25, 2012). U of Michigan Public Law Working Paper No. 277, 7th Annual Conference on Empirical Legal Studies Paper, Available at SSRN: https://ssrn.com/abstract=2092195 or http://dx.doi.org/10.2139/ssrn.2092195

Samuel R. Gross (Contact Author)

University of Michigan Law School ( email )

625 South State Street
Ann Arbor, MI 48109-1215
United States
734-764-1519 (Phone)
734-764-8309 (Fax)

Michael Shaffer

University of Michigan Law School ( email )

625 South State Street
Ann Arbor, MI 48109-1215
United States

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