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Estimating the Prevalence of Wrongful Convictions

NCJ Number
Date Published
May 2017
16 pages
This study extended research on wrongful convictions in the United States and the factors associated with justice system errors that lead to the incarceration of innocent people.
Among cases in which physical evidence produced a DNA profile of known origin, 12.6 percent of the cases had DNA evidence that would support a claim of wrongful conviction; however, extrapolating to all cases in this study's dataset, it estimated a slightly smaller rate of 11.6 percent. This finding was based on forensic, case-processing, and disposition data collected on murder and sexual assault convictions in the 1970s and 1980s across 56 circuit courts in Virginia. The study focused on 714 murder and sexual assault felony cases to estimate the rate of wrongful convictions. The estimate of 11.6 percent is different from prior estimates reported by the Urban Institute in 2012, due to both a more refined scope and additional context for case files. The current study examined Bureau of Justice Statistics data collected from felony courts in 1985 in order to determine whether this new estimated rate of wrongful convictions can be generalized to other states across the United States. The current analyses indicate that the rate of dismissal in Virginia is not significantly different from other states. This research is the only known effort to apply DNA testing to cases regardless of a person's individual claim of innocence. The process by which case outcomes are revised by considering court processing and case disposition information highlights the limits of DNA evidence in identifying potential instances of wrongful conviction. Also, although most post-conviction efforts to show an erroneous conviction rely on DNA testing only when the conviction is probably wrong, the current work puts the DNA testing at the front end, which simultaneously used DNA to identify both wrong convictions and right convictions. Future analyses will include a determination of whether the data collected correlates with instances of potentially wrongful conviction and will present findings on the utility of DNA as a detection tool for wrongful convictions. 1 table and 12 references

Date Published: May 1, 2017