Until March 2009, few Americans had heard of Ronald Cotton, who was convicted in North Carolina of raping a college student and served 11 years in prison before being exonerated by DNA testing. Now Cotton is a household name because of a book about his case and appearances on “60 Minutes” and NBC's “Today” show. As recently as 10 years ago, the proposition that innocent men and women regularly end up in prison failed to find traction. Today, thanks to the power of DNA evidence, media coverage and the establishment of innocence projects, there is general acceptance that wrongful convictions indeed occur. Dozens of states have passed laws to prevent wrongful convictions and compensate those wrongly imprisoned. Defense attorneys and many academics say wrongful convictions are a recurrent problem requiring substantial changes in the criminal justice system, but prosecutors, police and other academics say mistaken convictions are such a small percentage of all cases that the system should mostly be left alone.