Revising State Post-Conviction Relief Statutes to Cover Convictions Resting on Subsequently Invalidated Expert Testimony

Abstract

Over 300 prisoners have already been exonerated by postconviction DNA testing. In many of these cases, the subsequent DNA testing demonstrated the invalidity of expert testimony that had been relied on as the basis for the prior conviction. Given the disturbing revelations of the weaknesses in many traditional types of forensic science, in the future there will probably be many more requests for postconviction relief on the ground that later scientific research has eroded confidence in the expert testimony that served as the basis for an earlier conviction. Some jurisdictions such as California and Texas have recently adopted new legislation to regulate granting postconviction relief on this ground. Initially, this article delimits its topic. The article differentiates between two issues: (1) the question of whether the prior expert testimony has been invalidated; and (2) the question of the impact of the prior expert testimony on the earlier conviction. This article focuses on question (1). The article then attempts to distinguish between situations in which subsequent research merely raises doubts about the validity of the prior expert testimony and those in which the research undermines the testimony so seriously that postconviction relief is warranted. After critiquing the new California and Texas statutes, the article offers guidance for reformers drafting legislation to govern setting aside convictions on the ground that new scientific research has overtaken the expert testimony that the prosecution relied on in the earlier conviction.