STUDIES: Researchers Find Root of Wrongful Convictions in Forensic Science Testimony

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.