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Slowly at first, and then with accelerating frequency, the courts have begun to examine, consider, and sometimes even require empirical data. From 1960 to 1981, for example, use of the terms "statistics" and "statistical" in Federal District and Circuit Court opinions increased by almost 15 times.1 Of course, citation rates indicate only that a topic is considered worthy of mention, not that it is taken seriously, or even understood. Nonetheless, in a number of areas, such as jury composition and employment discrimination, the courts have come to rely on empirical data as a matter of course.

In the last 25 years, empirical research has been central to most major challenges to the constitutionality of capital punishment. The research involved has covered an enormous range of methods, from surveys to simulations, from econometric analyses to laboratory experiments, and the presentation of the research to the courts has generally been both comprehensive and sophisticated. There is probably no other area of criminal law in which the Supreme Court has been faced with such well-organized and wide-ranging empirical demonstrations. It is quite likely that comparable empirical data about some other issue would be persuasive to the Court; when the issue is the death penalty, however, the Court is not persuaded. In case after case, the majority of the Justices have been faced with empirical research that supports an outcome they do not want.

Three major empirical questions have been brought before the Court in relation to capital punishment. The first is the issue of deterrence: Is the death penalty more effective than life imprisonment as a deterrent to murder? The second is the issue of discrimination: Are decisions about which criminals should be executed and which should be allowed to live based in part on the race of the person accused or on the race of the victim? The third is the issue of the fairness of capital juries: Does the common practice of removing strong opponents of capital punishment from the jury create juries that are biased toward a guilty verdict? The Court has dealt with the data on each of these issues somewhat differently-sometimes by calling them inconclusive, sometimes by calling them irrelevant, and sometimes by evading them. I shall examine the Court's use of the data presented on each of these three questions, the first two briefly, and the third at greater length.


Reproduced with permission.