Summary
U.S. Supreme Court case regarding how to decide whether a convicted murderer is intellectually disabled, and thus exempt from the death penalty, when multiple IQ tests have been done. Joseph Smith was released early from his prison sentence for robbery on a community custody program. Two days later he and and an accomplice murdered Durk Van Dam in order to rob him, brutally beating him and cutting him with a power saw. Smith voluntarily confessed to the crime. At the time of his trial, mental retardation (as it was then known) was a mitigating circumstance but not a complete exemption from the death penalty. Smith's lawyer hired an expert who administered an IQ test and testified at trial. The jury decided that the mitigating circumstances, including mental condition, did not outweigh the aggravating circumstances, and the trial judge agreed. Smith was sentenced to death. Between Smith's school days, the trial, and post-conviction litigation, Smith was tested for IQ five times, with scores of 75, 74, 72, 78, and 74. An IQ of 70 or less is generally regarded as one of the three requirements for the diagnosis of intellectual disability. The U.S. District Court and the Court of Appeals for the Eleventh Circuit held that because 70 is within the 95% confidence interval for four of the tests (although just barely for three of them), that was sufficient to move on to the second and third requirements of the diagnosis. They further held that the inmate's experts were more convincing than the state's and overturned the sentence. After the U.S. Supreme Court took up the case, CJLF filed a "friend of the court" brief argument that the lower federal court had failed to adequately consider the well-established principle of aggregation. That principle tells us that repeated measures taken together are more precise than the margins of error of the individual tests. There is no consensus on how to combine the scores, but our brief does the math in several different ways to illustrate that they all lead to the same conclusion. The probability that Smith actually has a true IQ less than 70 is remote. This is combined with the fact that he has already presented his mental condition—however it might be labelled—as a mitigating circumstance at trial and it was found to be outweighed by the aggravating facts of this brutal crime and his criminal record. Under these circumstances, the state is justified in proceeding to execute the judgment.
