Research Corner Search by Key Word



John Roman, Kelly Walsh, Pamela Lachman, and Jennifer Yahner 
Post-Conviction DNA Testing and Wrongful Conviction 
Washington, D.C.: Urban Institute, 2012
After 1990 DNA exonerations helped spark the innocence movement. Critics argued that reported exonerations, even if a few thousand, are a tiny fraction of the one million felony convictions handed down every year. Innocence reformers argued that legal exonerations are the tip of an iceberg. 
Before the Urban Institute (UI) report was published in June 2012, the best studies of the incidence (rate or proportion of cases that occur in a given time period) of wrongful convictions were three studies of murder or death penalty cases where the numerators were exoneration cases and the denominators were similar kinds of cases. These studies found death penalty errors rates from 2.3% to 3.3%. 
Scholars believe it is not proper to extrapolate these figures to a general rate of wrongful conviction. 
First, errors may be higher in death penalty than in non-capital cases. Second, the samples for these studies were driven by cases exoneration cases, only after the tremendous  effort taken for an innocent prisoner to be exonerated. 
Mary Jane Burton worked as a forensic serologist for Virginia’s state crime laboratory from 1973 to 1987. Cases were assigned randomly to forensic serologists. She routinely attached cotton swab heads and textile clippings to the worksheets in her hard-copy case files, a practice not done by colleagues.  This was noticed when DNA exonerations were obtained in Virginia. Burton’s case files raised the possibility of testing a general population of cases that were not pre-selected because they were believed to be exonerations 
With state authorization and federal funding the UI reviewed 534,000 Virginia convictions, found 3,000 with retained physical evidence, 2,100 where a suspect was identified, and 740 with at least one felony conviction. From this sample, the UI selected 634 cases with 715 convictions in sexual assault and homicide cases. An independent laboratory conducted DNA tests on the crime kit samples and the convicted person’s DNA. UI gathered or collated other evidence related to the case. 
Roman and his colleagues found that in 5.3% of the cases the offender was eliminated as a source of DNA and the DNA exclusion was accompanied with probative evidence that appeared to support exoneration. In another 2.5% of the cases the offender was eliminated as a source of DNA, but the exclusion was not accompanied with probative exoneration evidence. This is the strongest empirical evidence to date that establishes the existence of a substantial proportion of wrongful convictions in a sample of general cases, rather than in group of cases that were targeted because they appeared to be miscarriages of justice.  
Although the study supports the tip-of-the-iceberg thesis, the findings should not be automatically extrapolated to other felonies and may reflect practices from 30 to 40 years ago. {sharethis}


blog comments powered by Disqus