In the forty year history of the Supreme Court's modern death penalty jurisprudence, two cases — Furman v. Georgia (1972) and McCleskey v. Kemp (1987) — stand out above all others. Both cases turned on the Court's consideration of empirical evidence, but they appear to have reached divergent — even altogether inconsistent — results. In Furman, the Court relied on statistical evidence that the death penalty was infrequently applied to death-eligible defendants to hold that the Georgia death penalty scheme was unconstitutional under the Eighth Amendment. In McCleskey, the Court, despite being presented with statistical evidence that race played a significant role in death-charging and death-sentencing in Georgia, upheld the revised Georgia scheme and McCleskey's death sentence against Equal Protection and Eighth Amendment challenges. The McCleskey decision called into question the use of statistical evidence to challenge the death penalty.
In the present article, we report on a unique empirical study of the administration of the death penalty in Alameda County, California — the largest single-county death penalty study and the only study to examine intra-county geographic disparities in death-charging and death-sentencing. The data set, drawn from 473 first degree murder convictions for murders occurring over a 23-year period, compares death-charging and death-sentencing in the two halves of the county. During the study period, the two halves differed significantly in racial makeup — the population of North County was over 30% African-American, and of South County less than 5% African-American; and the two halves differed in the race of homicide victims — in North County, African-Americans were homicide victims roughly 4.5 times as often as Whites, while, in South County, Whites were homicide victims more than three times as often as African-Americans.
The study reveals that there were statistically significant disparities in death-charging and death-sentencing according to the location of the murder: the Alameda County District Attorney was substantially more likely to seek death, and capital juries, drawn from a county-wide jury pool, were substantially more likely to impose death, for murders that occurred in South County. We argue that, McCleskey notwithstanding, statistical evidence such as the "race of neighborhood" disparities found in the present study should support constitutional challenges to the death penalty under both the Equal Protection Clause and the Eighth Amendment.
An attempt to provide understandable and up-to-date information regarding intelligence testing, intelligence theories, personal competence, adaptive behavior and intellectual disability (mental retardation) as they relate to death penalty (capital punishment) issues. A particular focus will be on psychological measurement, statistical and psychometric issues.