At one level, the answer is that DNA was never the cure-all some expected. In 2014, only 18 percent of the reversed convictions (22 out of 125) occurred after DNA testing proved innocence. This reflects the reality that relevant DNA is available only in a tiny minority of cases. CSI dramas are fantasy; in real life, science can't solve most crimes. At the same time, risk factors that we now know lead to wrongful conviction — eyewitness misidentification, junk science, false confession, ineffective assistance of counsel and police misconduct — are present in thousands upon thousands of cases that pass through our system every year.