Innocents convicted: an empirically justified factual wrongful conviction rate.

AuthorRisinger, D. Michael

That would make the error rate [in felony convictions] .027 percent--or, to put it another way, a success rate of 99.973 percent.

--Justice Antonin Scalia. concurring in Kansas v. Marsh, June 26, 2006 (quoting Joshua Marquis). (1)

  1. INTRODUCTION

    The news about the astounding accuracy of felony convictions in the United States, delivered by Justice Scalia and Joshua Marquis in the passage set out epigrammatically above, would be cause for rejoicing if it were true. Imagine. Only 27 factually wrong felony convictions out of every 100,000! Unfortunately, it is not true, as the empirical data analyzed in Part III of this article show. Part IV then deals with the impact of an empirically derived factual innocence rate (2) for at least one important category of real world criminal convictions (capital rape-murders in the 1980s) on various participants in current debates on both the death penalty and the problem of convicting the factually innocent generally. Part V examines the problem of generalizing the factual innocence rate from capital rape-murder convictions in the 1980s to other times and other crimes. Part VI provides a lens through which to view the moral and policy implications of such a factual innocence rate. But first, some historical context:

  2. PALEYITES AND ROMILLISTS

    People who think about the problem of wrongful conviction often fall into two camps, which we might label Paleyites and Romillists. Paleyites, whom I have named after the early exponent of this position, the 18th-century proto-utilitarian the Rev. William Paley, believe that, even though it is wrong to convict an innocent person, such convictions not only are inevitable in a human system, but represent the necessary social price of maintaining sufficient criminal law enforcement to provide an appropriate level of security for the public in general. Hence, one should not be moved by the prospect of wrongful conviction to take actions that would reduce such convictions, no matter how common, at the cost of reducing convictions of the guilty to a dysfunctional level. (3) Paleyites tend to be conservative, in the sense that any changes to current ways of conducting the criminal justice process, proposed for their supposed effect on protecting the innocent, will be presumed so counterproductive in their effect on convicting the guilty that they will be opposed.

    Romillists, whom I have named after the early 19th-century reformist Sir Samuel Romilly, have such a horror of convicting the innocent that they are willing to propose many changes to whatever system exists, on the ground that such changes in our way of criminal law enforcement will better protect the innocent. (4) In so doing, it may be that some of the proposals might make the conviction of the truly guilty more difficult, perhaps significantly so. Whatever the actual effect, the Paleyites can be counted on to find the potential effect abhorrent, and to label the proponents "soft-headed sentimentalists" or some similar characterization, while the Romillists in turn will label the Paleyites hard-hearted troglodytes, indifferent to the plight of the convicted innocent, with knee jerk opposition to reform.

    What neither side has a good handle on, however, is the magnitude of the problem of factually wrongful conviction and wrongful acquittal. Partly this is due to the inherent difficulty of establishing the ground truth of factual guilt or innocence better than the trials (or plea bargains) that resulted originally in acquittals or convictions. But, at least with regard to convictions, it is also partly due to the fact the legal system is structured to operate as if it were controlled by Paleyites, whatever the personal beliefs of individual participants. This is the result of rather extreme doctrines intended to uphold the integrity and finality of the results of criminal trials. (5) Nevertheless, both post-conviction legal doctrines and those who administer them, prosecutors and judges alike, resist new evidence of innocence to such a degree that it often passes the bounds of rationality. (6) And what but the word "concealment," albeit in the name of protecting the public legitimacy of the system, can explain the efforts undertaken to oppose DNA testing in regard to those already executed, where such DNA testing would conclusively establish guilt or innocence in fact. (7)

    Traditionally, a certain stripe of Paleyite has also denied that wrongful convictions happen at all, or, that if they happen, they happen so rarely that worrying about them is like worrying about being struck by a meteorite. (8) The reasons assigned for this assumed near-perfection in regard to false-positive error have generally been the numerous layers of filtration involved in the pre-trial system, and the general fairness of the adversary trial itself, with its formal requirement that the prosecution prove guilt beyond a reasonable doubt. (9)

    Such a position is very difficult to take in the era of DNA exonerations. Difficult--but not impossible. As one can see from the epigram at the beginning of this Article, Paleyites such as Justice Scalia and Joshua Marquis still speculate about, and embrace, ludicrously low wrongful conviction rates. However, such speculation has become both obsolete and untenable, since, as I propose to demonstrate, the data and the elementary statistical tools necessary to arrive at a reliable minimum rate of factually wrongful conviction, at least in a certain significant subset of cases, are actually to hand. And from this specific minimum innocence rate other inferences may defensibly be drawn about the problem of factually wrongful conviction. Once Paleyites and Romillists are forced to agree on at least a partial description of the problem of factually wrongful conviction, they can then proceed to develop and set out informed normative responses to the empirical reality.

  3. AN EMPIRICALLY JUSTIFIED FACTUAL WRONGFUL CONVICTION RATE: THE CASE OF CAPITAL RAPE-MURDERS IN THE 1980S

    In order to derive a minimum factual wrongful conviction rate (a factual innocence rate), we must, of course, have a numerator and a denominator. The denominator would represent a certain reference set of convictions, and the numerator would represent the number of factually wrongful convictions in the reference set. We might look for our numerator in the number of exonerations that have taken place over a certain period of time, whether based on DNA evidence or not. (10) I have chosen, however, to include only DNA exonerations as part of a numerator, in order to avoid the epistemic problems that could arise in regard to any rationally debatable exonerations, (11) since it is easiest to establish DNA exonerations as being close to indisputable cases of factually wrongful conviction. (12)

    So let us look for our numerator somewhere in the statistical pool provided by the DNA exonerations, and then define the boundaries of the universe of cases these exonerations represent, in order to find a denominator and establish a minimum rate of factual innocence for that universe of cases. Then we can examine the question of what the DNA cases can tell us in general about rates of wrongful conviction and factual innocence.

    To obtain a proper sample of DNA exonerations to work with, one must understand that the cases in which DNA exonerations occur are by definition not a random sample of all cases of criminal conviction. Virtually all such exonerations occur in cases of serious felony, often capital felony, in which a trial resulted in a conviction. The DNA exonerations can usefully be divided into four groups: capital cases, (13) noncapital homicide cases, non-capital rape/sexual assault cases, and others. The most obvious group to examine in searching for a denominator is the capital cases. This group consists of an externally defined set of capital cases of finite and known number in the United States during the period of time since the reestablishment of the death penalty in 1976 from which such exonerations are drawn. These would be specifically the capital sentences imposed from the date of the first such conviction that finally culminated in a DNA exoneration, to the date of the latest trial of the case finally culminating in the capital DNA exoneration, roughly 1977 to 1999. (14) There are fourteen capital-case DNA exonerations so far in cases tried from 1977 to 1999. During that same period of time, 5968 capital sentences were imposed. (15) These figures give an absolute minimum factual error rate for capital sentences imposed during that period of .23%.

    Whether the imposition of a death sentence on a factually innocent person two or three times out of every thousand impositions of capital punishment is too high a rate is a heavy question of morality and policy. But of course this percentage does not represent the actual rate of factually wrongful conviction. In fact, it is clearly grossly understated, because we are using the wrong denominator. (16) The choice of the right denominator is what makes it empirically defensible to derive a factual innocence rate from the DNA exonerations. We must therefore carefully define the boundaries of the universe of cases represented by the group of DNA exonerations chosen. (17)

    The DNA exonerations can only occur in the subset of capital convictions in which it is reasonable to believe that bodily sources of DNA might have been left in such a way as to provide the basis for including or excluding a defendant as the possible perpetrator. Generally, in capital case exonerations, this has meant what can be called "rape-murders," generally homicides where the victim is raped, then killed. In fact, thirteen of the fourteen DNA exonerations in capital cases involved rape-murders. (18)

    Looking at these thirteen cases, two important points emerge about the window that the DNA exonerations open on the problem of wrongful conviction rates in general. First, that window is...

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