Innocence project: DNA exonerations, 1989-2014; review of data and findings from the first 25 years.

AuthorWest, Emily
PositionElephants in the Courtroom: Examining Overlooked Issues in Wrongful Convictions

    During the last quarter century there have been 325 DNA exonerations in the United States (1989-2014). What seemingly started out as a few tragic examples of wrongful convictions has turned into a growing body of cases (and individuals), allowing for deep investigation and research to determine why these injustices occur and how they might be prevented.

    This 25-year mark provides a meaningful opportunity to reflect on what we have learned about the wrongful convictions and how they can inform the conversation around criminal justice policies and practices. As such, this report offers a first-time comprehensive review of data collected by the Innocence Project (IP) on DNA exonerations. It is designed to be a useful tool to better understand what these wrongful convictions involved and to promote more discourse and action on the issues across multiple arenas (academia, policy, litigation, journalism and the public).

    The data presented in this report comes from a comprehensive database developed by research staff at the IP. The information contained in the database comes from trial transcripts, police and forensic laboratory reports, public appeal decisions, post-conviction lawyers representing the exonerees and reputable media sources. (1)

    The cases in the database and profiled on the IP website are not limited to those for which the IP provided counsel. While the IP played a role in the majority of these DNA exonerations, others were the result of dedicated representation by Innocence Network member organizations, and/or by unaffiliated legal organizations or private lawyers. (2)

    Cases that appear on the IP list include post-conviction DNA exonerations in the United States where DNA testing results were central to establishing the innocence of the wrongfully convicted individual. The definition of a post-conviction DNA exoneration that qualifies for this list is a case where DNA testing results were dispositive of actual innocence and central to vacating the conviction and/or dismissing the indictment. The indictment must have been dismissed, the defendant pardoned on the grounds of innocence or acquitted at a retrial.

    As a result of the aforementioned criteria, the exonerations represented here are made up largely of sexual assaults and murders, as these are the types of cases that are most likely to have biological evidence left behind by the perpetrators that can be subjected to DNA testing and where the DNA is most likely to be dispositive of innocence.

    This report will provide rich details on case facts and demographics including crime facts (dates, geography and type of crime), exoneree and crime victim characteristics, data on guilty pleas and sentences and information on the real perpetrators of these crimes. This will be followed by detailed sections on each of the main contributing factors associated with these wrongful convictions (misidentification, the misapplication of forensic science, false confessions and use of informants), along with brief descriptions of relevant research, as applicable, to help frame each issue.

    The next section will include information on financial compensation sought and received in the aftermath of these wrongful convictions. The report will conclude with final remarks and reflections.

    It is important to highlight what is not included in this report as well. To begin with, while we address many factors that contributed to these wrongful convictions, some factors are more difficult to document, define and uncover, therefore they are not offered in the analysis here. Prosecutorial misconduct is one such example. We know of examples from the DNA exonerations of cases where prosecutors withheld exculpatory evidence from the defense--a legal and ethical violation. (3) We also know of some cases--through publicly available court decisions--where appellate courts confirmed prosecutorial misconduct at the trial-level prior to an individual's exoneration based on DNA evidence. (4)

    However, it is very difficult to determine the full scope of prosecutorial misconduct in these cases. First, there is little consensus on how to define prosecutorial misconduct (e.g., Any ethical violation? Only misconduct confirmed through courts? Only egregious cases where intent is established?). Second, it is impossible to document/discover all potential misconduct cases. Whereas one can without too much effort determine whether a case involved a misidentification by a witness, determining whether a prosecutor turned over any/all exculpatory evidence to the defense is a much more difficult task. Similar definitional and discovery problems are present when trying to measure ineffective assistance of counsel, police misconduct and issues of racial discrimination. (5)

    Next, while applicable research is described briefly when it is relevant to placing statistics in perspective, this report will not offer a rich literature review on each of the contributing factors. To do justice on this front would necessitate a much lengthier paper or book and the focus of this report is the comprehensive data available on these DNA exonerations.

    Finally, this is a research report, not one focused on policy. Therefore, while the lessons learned from DNA exonerations drive the IP's policy goals, those complex and detailed efforts are not presented here. The IP website contains a wealth of information on policy reform for those interested in this aspect of the IP's work. (6)


    To date, there are two central national lists of known wrongful convictions. (7) The first is the IP list, which is limited to exonerations based on DNA evidence. (8) The second list includes both DNA and non-DNA exonerations and comes from the National Registry of Exonerations (NRE)--a joint project of the University of Michigan Law School and the Center on Wrongful Convictions at Northwestern University School of Law. (9)

    The total number of exonerations nationwide on the NRE list stood at 1,529 by the end of 2014. While the NRE list contains the IP DNA exonerations, the majority of the cases are convictions that were overturned on grounds relating to innocence but based on evidence other than DNA. As the keepers of that list readily admit, without DNA it can be very difficult to definitively prove innocence, and they are careful to review cases, to the best of their ability, to only include those where there is compelling evidence of innocence.

    There are important distinctions that emerge when comparing the contributing factors among the wrongful convictions across the IP and NRE lists. For example, while eyewitness misidentification continues to be the overall leading contributing factor in DNA exoneration cases, false accusation/perjury is the leading contributor among the cases listed on the NRE website. This has to do with the very different distributions of crime types across these two lists, as well as additional types of crimes that are not represented on the IP list, such as fraud, drug crimes and crimes that never happened (e.g., fabricated child abuse cases, deaths later determined to be of natural causes).

    Additionally, in cases where DNA is not available to prove innocence, deeper investigation into the cases is needed and often reveals problems that may also have been present in some DNA cases, but not discovered because the investigation ended when exonerating DNA evidence was obtained. (10)

    Due to these aforementioned differences, it is important to note that the patterns and trends discussed in this report are limited to the types of crimes represented in the DNA exoneration cases--again, largely sexual assault and homicide or other violent crimes where biology from perpetrators is left behind. Despite the IP's list being a subset of all exonerations, interest in the IP list remains steadfast, as it represents the "gold-standard" of cases where innocence is established by undisputed science.

    It is also worth noting that the IP's list--and indeed the NRE list--represent but a fraction of all wrongful convictions. This is because most wrongful convictions are never brought to light. Professor Samuel Gross has written on this subject frequently and discusses why we know so little about the true rate of false convictions. (11)

    The wrongful convictions that have been uncovered tend to be for serious crimes that result in long prison sentences (sexual assaults, homicides and other violent crimes). Innocent people sentenced to short jail/prison terms may never seek help, either because they do not know how to get help, or because it is easiest to just serve the time and attempt to move on. Those who do seek help are not likely to find someone able to take on their claims of innocence. Most lawyers and organizations that provide services to those claiming innocence focus on prisoners who still face years behind bars. Further, crimes like robbery, involving strangers are likely to rely heavily on eyewitness identification, similar to sexual assault. However, the reason we know about the dangers of misidentification in sexual assaults is because in those cases there was probative biological evidence left behind, allowing for DNA testing to identify the perpetrator. In most robbery cases there is no useful biological evidence left behind to identify the perpetrator and therefore potential innocence cannot be established, but certainly the same pitfalls of eyewitness identification exist in those crimes, too.

    Finally, there is a certain amount of luck involved in the exonerations that have occurred. An exoneration may depend on such things as a prisoner getting the attention of a dedicated advocate who pushes the case forward; witnesses or informants coming forward years later to say they lied; or a real perpetrator offering a confession which is then corroborated with other evidence. In addition, in cases where forensic science evidence is central to establishing...

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