A three-year study conducted by the Washington Institute for Public and International Affairs Research at American University has identified 10 factors common in wrongful convictions, as opposed to cases in which innocent defendants are acquitted or have their charges dismissed before trial.
Funded by the U.S. Justice Department's National Institute of Justice, the first-of-its-kind study, called "Predicting Erroneous Convictions: A Social Science Approach to Miscarriages of Justice," sought to identify why innocent people in the United States go to prison for violent crimes they didn't commit. The study was released March 11.
The researchers, led by Jon Gould, identified 460 erroneous convictions and "near miss" cases [the ones involving acquittals or dismissals of innocent defendants], from 1980-2012. They found 10 factors that can be used to accurately predict when an erroneous conviction might occur, versus a near miss. The research team included Richard Leo of the University of San Francisco School of Law, an expert on police interrogation and wrongful convictions.
"[T]he only way to establish what causes an erroneous conviction is to understand which factors are exclusive to erroneous convictions as against other sets of cases," the study found. "Missing so far in the literature is a study that asks how the criminal justice system identifies innocent defendants in order to prevent erroneous convictions." (italics original)
The 10 factors identified by Gould and his team included the state's death penalty culture, or state's "punitiveness," meaning the number of executions per population; the strength of the prosecution's case; the strength of the defendant's case; whether the prosecution withholds evidence (commits Brady violations); forensic evidence errors; the age of the of defendant; the defendant's criminal history; intentional misidentification; lying by non-eyewitnesses; and the use of family witnesses to testify on behalf of defendant.
According to Gould, prevention begins at the police station starting with the interrogation and investigation of alibis, which if not conducted carefully can lead to a "perfect storm" of errors made worse by collective tunnel vision.
In an interview, Gould said the most surprising finding was that "a prosecutor with a weak case focuses on an accused [person] even more intently, rather than considering alternative suspects precisely because tunnel vision has set in – in other words, the case seems to add up from the investigation but is sufficiently weak relying on perhaps a misidentification."
Some of the solutions Gould offered are the use of checklists by police to make sure they are looking at all aspects of cases, which he said they do particularly well in cases where the defendant has an alibi. Doing forensic testing early in a case and training are also important, he said.
However, Gould said one flaw is that when an error occurs in a case, the justice system often does not have a vehicle to investigate to try to prevent similar errors from occurring in other cases in the future.
"Surprisingly, unlike airplane crashes where the National Transportation Safety Board moves in to investigate and reconstruct events in an effort to prevent future catastrophes," he said, "wrongful convictions have not often been investigated beyond case studies."