A groundbreaking study by Brandon Garrett and Peter Neufeld published in the Virginia Law Review explores erroneous scientific testimony by prosecution experts in the trials of defendants who were later exonerated through DNA testing. The research, “Invalid Forensic Science Testimony and Wrongful Convictions,” explored serological analysis and microscopic hair comparison, bite mark evidence, shoe prints, soil, fiber, fingerprint comparisons, and DNA testing. In 60% of the trials, the prosecution’s forensic analysts provided invalid testimony with conclusions that misstated empirical data or was completely unsupported by empirical data. Flawed expert testimony was not an isolated issue stemming from a handful of analysts. In the 137 cases examined, inaccurate testimony was delivered by 72 prosecution forensic experts, employed by 52 laboratories, practices, or hospitals from 25 states. The study also discovered that the defense counsel rarely cross-examined analysts concerning invalid testimony and rarely obtained experts of their own. The paper may be read here.
(B. Garrett & P. Neufeld, "Invalid Forensic Science Testimony and Wrongful Convictions," 95 Virginia Law Review 1 (2009)). See Innocence and Studies.