A national policy group examined the DNA test results in hundreds of old sexual assault and homicide cases. The findings on the sexual assault cases are disturbing.
According to the Virginian-Pilot: "If the scope is narrowed to just the sexual assault convictions, DNA testing eliminated between 8 percent and 15 percent of convicted offenders. The wrongful conviction rate previously had been estimated at 3 percent or less."
The study was based solely on DNA evidence, which means it did not count wrongful convictions where the defense was consent (e.g., "date rape"). Moreover, in two-thirds of the cases, the samples didn't have enough DNA for testing, and "that may mean the number of false convictions is much higher." http://presstv.com/usdetail/246990.html and http://hamptonroads.com/2012/06/study-dna-tests-show-scale-bad-convictions-va
These numbers are sufficiently disturbing that they should trigger a national dialogue.