Check out the very important work being done by Roger Koppl and his associate Jim Cowan of the Institute for Forensic Science Administration (for an accessible overview of Roger and Jim’s work see Roger’s Forbes interview from a few years back). To get a sense just how vital their work is consider the stats cited in their paper:
There are over one million felony convictions per year. Risinger (2007) has established that the “minimum factual wrongful conviction rate” for capital rape-murders from 1982 through 1989 is at least 3.3% (pp. 768 & 778). The study of Saks and Koehler (2005) suggests that about two thirds of false convictions arise in part from forensic science testing errors or false or misleading forensic science testimony. Multiplying these numbers gives you a number greater than 20,000.