An actuarial risk of assessment of violence posed by murder defendants.

• Author: Sorensen, Jonathan R.

The Supreme Court held in Furman v. Georgia(1) that capital punishment was unconstitutional due to the arbitrary nature of then-current sentencing statutes. Citing jury discretion as the cause of inconsistent sentencing practices, the Furman decision invalidated the capital punishment statutes of all retentionist jurisdictions in the United States. In order to address the Court's central concern--whether death sentences were imposed in a uniform and fair manner--state legislatures revamped their capital punishment statutes to limit jury discretion. In the decisions that followed, the Court clarified which procedures would be acceptable, upholding statutes that guided juror discretion,(2) but striking down those that mandated a death sentence for particular types of murder.(3) Since that time, death penalty jurisprudence has focused on how to insure consistency in decision-making while providing fairness to individual defendants.(4)

Concern for fairness led the Court to rule that states must allow evidence of nondangerousness as a mitigating factor in the punishment phase of capital trials.(5) The goal of incapacitating dangerous offenders prompted twenty-one states to include a defendant's potential for future violence among the aggravating circumstances jurors may be directed to consider before reaching a punishment decision.(6) Texas and Oregon, however, are the only two states that require capital juries to predict future conduct before sentencing. Specifically, a jury in these two states must unanimously agree there is "a probability that the defendant would commit criminal acts of violence that would constitute a continuing threat to society" before imposing a death sentence.(7) This requirement has thrust death penalty decisions into the realm of the subjective once again.

Studies have found the fate of capital defendants in Texas and Oregon is determined almost entirely by juries' deliberations on, and emotional responses to, the punishment inquiry concerning defendants' future dangerousness. In Texas during 1974 through 1988, jurors returned life sentences in 126 cases. In 85% (107) of these cases, the life sentences resulted from jurors' failure to find evidence that the defendant would pose a continuing threat to society.(8) A study of twenty-seven Oregon jurors from nine capital murder trials found that each of the life sentences issued was due to the inability of jurors to agree on the issue of future dangerousness.(9) The authors of the Oregon study concluded that under the Oregon statute, "the issue of future dangerousness plays a prominent, if not central role. Virtually all disagreements and prolonged discussion concerned only the second question of future dangerousness. Jurors clearly perceived the penalty decision as hinging on this issue."(10)

Narrowing the scope of deliberations to future dangerousness encourages jurors to contemplate their worst fear, that the defendant may kill again, while simultaneously quashing discussions over issues related to deservedness.(11) States in which jurors are directed to weigh specified aggravating and mitigating factors have average jury death sentencing rates ranging from approximately one-fourth to one-half that of life sentences.(12) In Texas, over three-fourths of all capital trials brought before juries during penalty trials between 1974 and 1988 resulted in death sentences.(13) Texas has clearly been the most active capital punishment jurisdiction in the United States, accounting for over one-third of all executions in the past two decades.(14)

Certain theoretical and pragmatic issues are raised by any sentencing system that uses the rationale of offender incapacitation to justify a penalty of death. First, the abstract philosophical question is raised as to whether it is ever acceptable to punish someone for crimes he has yet to commit.(15) Sentencing a defendant to death because of some act he may commit in the future is troubling for those opposed to such teleological forecasting(16) and seems to contradict the "innocent until proven guilty" premise of the American judicial system. Despite these concerns, however, the U.S. Supreme Court has upheld the future dangerousness, provision of the Texas statute on numerous occasions.(17)

A more concrete issue concerns how future dangerousness can be most accurately predicted, if at all. Several factors in the decision-making process encourage jurors to overestimate the threat of violence posed by capital murderers. Foremost among these is the lack of objective information regarding the likelihood of repeat violence. Recent research on jury deliberations has shown that jurors' assessments of future dangerousness is highly subjective.(18) Influenced by stereotypical images of the violent recidivist--the psychopathic serial killer disproportionately portrayed in the media and the new "true crime" genre of television shows(19)--jurors seldom realize research has consistently found the true incidence of recidivism among murderers released from prison to be much lower than for other types of parolees.(20) In researchers' terminology, jurors fail to consider the base rate of recidivism. Studies show the likelihood of repeat murders ranges from .1% to 7% per year, with the average being less than 1%.(21) One study of capital murderers commuted as a result of the Furman decision found that 188 murderers were paroled by the end of 1987, serving an average of 5.3 years in the outside community.(22) Only one killed again, for a rate of .1% committing repeat homicides per year. Six of the 188 committed violent offenses, resulting in a violent recidivism rate of .6% per year.(23)

Jurors also overestimate the opportunity inmates will have to commit acts of violence in the outside community. Texas jurors who have served on capital murder trials consistently underestimate the number of years that must be served by a capital murderer receiving a life sentence, with the average juror believing a person sentenced to life in prison will be paroled after 5 years.(24) Under current Texas law, capital murderers must serve at least 40 years of flat time before becoming eligible for parole.(25) In a recent denial of certiorari, four Supreme Court justices chastised the State of Texas for refusing to inform jurors of the mandatory minimum number of years to be served by capital defendants who are given a life sentence.(26) As Justice Stevens noted in Brown v. Texas(27), failure to provide this information unfairly "tips the scales" in favor of a death sentence.(28) The significance of this realization is twofold. A mandatory 40-year prison term makes the potential risk period in the outside community much shorter and the defendant much older upon release.(29) Parolees with these characteristics have demonstrated the lowest rates of recidivism.(30)

Prison violence is also greatly overestimated by jurors. The constraints of the prison environment reduce violence potential among its charges, with rates of homicide in prison being far lower than rates of homicide in the free community.(31) The yearly rate of repeat murder in prison has been found to be .002 or less for murderers in general.(32) This rate is consistent in situations where capital murderers serving life without parole and capital murderers serving death sentences were placed in the same general prisoner population.(33) Murderers commuted from death sentences also have a repeat murder rate of about .002.(34)

Most jurors are unaware that both correctional administrators and inmates agree that murderers are generally among the most docile and trustworthy inmates in the institution.(35) Empirical studies support these views, finding an inverse relationship between sentence length or time served and disciplinary infractions.(36) This relationship is also found in the case of assaultive behaviors.(37) Studies of capital murderers determined the base rates of violent rule infractions to be .06 per year or less.(38)

Though consistency in base rates exists, the pattern of violation over the course of an inmate's confinement must also be taken into consideration when assessing risk. Studies have shown that long-term inmates have stable rates of rule violation throughout the first few years of their sentences.(39) The pattern of rule violation among murderers specifically has been found to be stable during the first few years of incarceration, declining slightly thereafter, especially among initially high-rate offenders.(40) This convergence toward the mean rate of violations suggests that institutional disciplinary mechanisms, the maturation of inmates, or a combination of the two are successful in restraining further violations. As in free society, age has been found to be the major determinant of rule-violating behavior in prison.(41)

To create a more reliable means of predicting prison violence, it is necessary to use variables other than time served and age. These same variables can also be used to categorize capital defendants according to levels of risk. While misconduct rates are generally low among incarcerated murderers, existing variance suggests the importance of searching for particular correlations within offense types.(42)

Mental health researchers recently began to focus on how violence is most accurately predicted by utilizing objective actuarial methods.(43) These studies typically include a broad array of predictor variables and carefully specify the probability with which particular types of violence are likely to recur.(44) Paul Meehl first distinguished actuarial from clinical predictions in 1954, defining the latter as a "psychological hypothesis regarding the structure and the dynamics of [a] particular individual" and characterizing the former as a "mechanical combining of information for classification purposes, and the resultant probability figure which is an empirically determined relative frequency."(45) The individuals making housing...