Freeing the Innocent: DNA Testing's First 25 Years


DNA testing has altered criminal justice. But what have we learned from the more than 300 documented DNA exonerations between 1989 and 2014? And what do we still need to know?

These questions were at the heart of a conference last week at Northeastern University School of Law in Boston that attracted the nation's leading scholars and advocates in the field, including Barry Scheck and Peter Neufeld of the Innocence Project; Brandon Garrett of the University of Virginia; Richard Leo of the University of San Francisco; Alexandra Natapoff of Loyola Law School-Los Angeles; and Dan Simon of the University of Southern California.

The evolution of deoxyribonucleic acid (DNA) testing since the 1980s has also enabled us to pinpoint the source of genetic defects, resolve paternity disputes and tackle debilitating diseases. But most Americans are by now more familiar with its utility as a lever to spring open prison gates for the innocent.

DNA has been successfully used as a front-end tool to solve cases by identifying the source of biological material left at a crime scene by a perpetrator—and as a back-end remedy to exonerate an innocent prisoner by subjecting that material to more advanced tests.

In the United States, the first exoneration of an innocent criminal defendant through post-conviction DNA testing occurred in 1989. More than 300 other defendants have since cleared their names through this means.

Deconstructing a quarter-century of DNA exonerations has given us a deep understanding about what went wrong originally in those cases. Those factors are now well-known: eyewitness misidentifications, false confessions, faulty forensic evidence, ineffective assistance of defense counsel, police and prosecutorial misconduct, and the use of jailhouse informants.

These factors seldom appear alone in a wrongful conviction. More often than not, multiple errors surface in a single case.

Armed with this knowledge, innocence projects and others have urged stakeholders to reform the criminal justice system to prevent similar miscarriages of justice in the future. Much progress has already been made. Every state has a post-conviction DNA testing statute empowering inmates to petition for access to biological evidence in their cases and perform scientific tests. Many jurisdictions have revamped their approach to eyewitness misidentifications, with Massachusetts, New Jersey and Oregon leading the way.

More than a dozen prosecutors' offices now have “Conviction Integrity Units” designed to investigate possible wrongful convictions and rectify those mistakes. Ralph Gants, Chief Justice of the Supreme Judicial Court of Massachusetts, gave a riveting speech at the conference about eyewitness misidentifications and developments in the Commonwealth's jurisprudence in this realm.

Yet we have a long way to go.

As Rachel Barkow of New York University and Barry Scheck noted at the conference, the quality of the Conviction Review Units varies considerably from office to office. Moreover, ineffective assistance of defense counsel remains a widespread, and largely unaddressed, problem. Overworked, underfunded and barely monitored indigent defense counsel struggle to exercise some of the most vital functions of criminal practice.

New York Law School Professor Adele Bernhard's research further indicates that courts are not yet holding defense attorneys accountable for poor lawyering at the pretrial and trial phases, despite the attention generated by the “Innocence Movement.”

Perhaps the most glaring current research question in the field relates to guilty pleas.

Alexandra Natapoff of Loyola contended at the conference that plea bargaining should be firmly placed on the list of factors that produce wrongful convictions. Plea bargaining is not just a process through which the innocent are convicted, but a cause in and of itself. Differential sentencing is a huge part of the problem. Defendants faced with a plea offer typically experience a perilous choice: take a lenient sentence upfront or risk a much more severe sentence if found guilty at trial.

This phenomenon, dubbed the “trial tax” by some critics, may generate an untold number of wrongful convictions as risk-averse, yet innocent, defendants choose to take the safest option and plead guilty. Exacerbating the problem are rules allowing prosecutors to refrain from disclosing evidence to the defense prior to the entry of a plea and a cultural norm in which judges rarely probe into the validity of plea deals. Unlike civil cases in which judges are actively engaged in settlement negotiations, courts in most states take a hands-off approach to the plea process, neglecting to intervene at all and permitting perfunctory plea allocutions to take place on the record with limited inquiry into the underlying facts.

We have almost no idea how many innocent defendants are wrongfully convicted through plea bargains. The public records in these cases are so slim, the evidence supporting guilt so unclear, that we are largely left to speculation.

We have learned a lot from 25 years of DNA exonerations, and the criminal justice system has changed significantly in response to this knowledge. But questions linger. And none are more pressing than those concerning the plea bargaining process.

There is reason to think that a sizeable number of innocent defendants fall prey to a plea bargaining regime in which the truth is a chip to be bartered away.

Perhaps the next quarter century of exonerations will shine a spotlight into this dark corner of our criminal justice system.

EDITOR'S NOTE: Papers solicited as part of the conference, entitled “Wrongful Convictions and the DNA Revolution: Twenty-Five Years of Freeing the Innocent,” will be published by Cambridge University Press in a volume edited by Prof. Medwed.

Daniel S. Medwed is a Professor of Law at Northeastern University School of Law, and Legal Analyst at WGBH News in Boston. He welcomes comments from readers. Twitter: @danielmedwed Email:

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