The WAIS-III and WAIS-IV: Daubert motions favor the certainly false over the approximately true.

Daubert motions oppose adjusting IQ scores. They argue that the rate of IQ gains over time (the Flynn Effect) cannot be set at 0.3 points per year with scientific exactitude; therefore, the adjustment formula that rate implies is inadmissible in capital cases. This ignores the fact that there is universal agreement in the scientific community that there have been substantial gains and that, therefore, the worst possible option is to simply leave inflated IQ scores unadjusted. That would undermine equity entirely. New data from the WAIS-IV are included in a meta-analysis of 14 combinations of Wechsler and Binet IQ tests. The overall average is a rate of 0.311 points per year; the average within Wechsler tests is 0.299 point per year. A new estimate of the extent to which the WAIS-III inflated IQs, even at the time it was normed, yields 1.65 points (rather than 2.34 points). However, two new studies comparing the WAIS-III to the Woodcock-Johnson III and the Kaufman Adolescent and Adult Intelligence Scale give huge estimates. It is recommended that WAIS-III scores be set aside and subjects tested on the WAIS-IV and the Stanford-Binet 5.