There is an interesting discussion of compensation to criminals who have been wrongfully incarcerated here
. There are multiple interesting points in this discussion, but one of the more interesting is that there have apparently been only 200 cases exonerated through DNA evidence. Given that there are about 2.19 million people in prison just today and that we are talking about cases over many years, this seems to me like an amazingly small number. Off the top of my head I don't how many of these people were in prison for murder or other serious crimes such as rape or robbery, but suppose that in any given year that it is conservatively 400,000. A rate of 20 per year or even 40 per year or even a total of 200 being exonerated seems remarkably tiny. Even the worst possible and obviously wrong number would imply that only .05 percent were wrongfully convicted. The normal saying is that it is better to let 10 guilty men go than wrongfully convict one. Well, in this case the DNA evidence alone shows you would rather let 2000 guilty go rather than wrongfully convict one. I have lots of problems with overly aggressive prosecutors and would have thought that alone would imply that many more cases would be overturned via DNA evidence, but this evidence on exonerations through DNA evidence, despite the publicity that it receives, is pretty meager.