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How Wrongful Convictions Happen – and How We Can Prevent Them

Every time someone is exonerated through DNA testing, the case is a “learning moment” to find out where the criminal justice system failed and how it can be fixed. The Innocence Project determines what caused each wrongful conviction that has been overturned through DNA testing – and identifies patterns across multiple cases. We also work with leaders in the field and people across the criminal justice system to develop reforms that can reduce the potential for wrongful convictions.

Causes of Wrongful Convictions

More than 200 people have been exonerated through DNA testing nationwide. Here is a breakdown of the factors that led to their wrongful convictions (multiple factors often contribute to a wrongful conviction):

Eyewitness Misidentification: In 77% of the DNA exonerations, eyewitness misidentification led to wrongful convictions. Often, witnesses or victims chose the wrong person in photo arrays or lineups. In many of the cases, white people misidentified African- American men, leading to wrongful convictions. Learn more here.

Forensic science problems: In 65% of DNA exoneration cases, problems with forensic science led to wrongful convictions. This includes limited science, such as blood-type testing, which can identify large populations of people but cannot identify single individuals like DNA can. Many of the cases involved unreliable science, such as bite marks or tool marks that are presented as scientific evidence but lack certainty or validity. Some of the wrongful convictions were caused by fraudulent forensic science, such as forensic analysts who intentionally give false testimony. Learn more here.

False confessions & admissions: In 25% of the wrongful convictions overturned through DNA, innocent people falsely confessed or admitted to crimes they did not commit. False confessions are sometimes the result of mental disabilities, other impairments (including drugs or alcohol), physical coercion, or fear of a harsher sentence. Sometimes it is not clear why someone confessed to a crime he or she did not commit, but the exoneration cases show that young people are particularly vulnerable to giving false confessions. Learn more here.

Snitch testimony: In 15% of the DNA exoneration cases, wrongful convictions were caused by testimony from snitches or police informants. Often, these people have an incentive to provide false testimony (for example, they are prisoners looking for a deal to reduce their sentences or they are facing criminal charges that will be dropped or reduced in exchange for testimony). Learn more here.

Government misconduct: Some wrongful convictions overturned by DNA were caused by improper government actions, including prosecutorial misconduct and police misconduct. Government misconduct is often concealed and difficult to prove, but it can have a particularly strong influence in convicting innocent people. Learn more here.

Bad lawyering: In some exoneration cases, the wrongful convictions were caused by inadequate defense attorneys. This includes attorneys who were over-worked and did not have the proper training or resources to do the job well. It also includes attorneys who were incompetent and did not try to defend their clients vigorously. Learn more here.

Remedies that Help Address and Prevent Wrongful Convictions

Access to post-conviction testing: There wouldn’t be any DNA exonerations if prisoners couldn’t get testing. Every state should have a law explicitly granting post-conviction DNA testing when it can prove innocence (without time limits and regardless of whether the person seeking testing pled guilty or confessed to crimes). Learn more here.

Eyewitness identification reforms: A substantial volume of research shows that simple changes to how lineups (both live and photographic) are conducted can result in more accurate identifications. This includes carefully selecting the “fillers” who are put in lineups, giving witnesses clear and consistent instructions before lineups and making sure that the officer administering the lineup does not know who the suspect is and who the fillers are. Learn more here.

Evidence preservation: In too many cases, crime scene evidence is lost or destroyed after a person is convicted. DNA testing can only overturn a wrongful conviction if the evidence has been saved and properly stored. States should have clear laws and policies on how evidence is preserved and stored. Learn more here.

Forensic science oversight: Broadly, national standards need to be enacted to make sure science that is used in courtrooms is valid and reliable. Individual instances of errors or misconduct in crime labs should be investigated and systemic problems should be fixed. There are already some mechanisms in place for crime lab oversight, and they should be used and enforced. New oversight commissions can help secure resources for crime labs while making sure problems in labs are addressed. Learn more here.

Exoneree compensation: The majority of people exonerated after proving their innocence have not been compensated for the injustice they suffered and the time they spent incarcerated. States should provide appropriate financial compensation, as well as critical services like healthcare, education and job training. Learn more here.

Recording of interrogations: Criminal interrogations should be recorded in their entirety so judges and juries can see the circumstances under which people sometimes admit or confess to crimes. Recording interrogations also helps prevent police misconduct. Learn more here.

Innocence Commissions: Many of the reforms outlined above can be addressed by a panel of state criminal justice experts that reviews the causes of wrongful convictions and makes recommendations to prevent future injustice. Learn more here.

What’s happening in your state? View our interactive map to find out.