A 7 percent exoneration rate may be grossly understating the problem. UVA’s Garrett suspects that the error rate may actually be as high as 17 percent. As he discovered in his own research, Barbour’s conviction, based on the testimony of a single eyewitness, reflects the reality that of the first 250 people exonerated by DNA testing, a whopping 76 percent were misidentified by eyewitnesses.