American IQ Gains From 1932 to 2002: The WISC Subtests and Educational Progress

Recent data from 12 pairs of tests representing eight standardization samples show that American IQ gains have occurred at a rate of 0.308 points per year from 1972 to 2002. Linked with earlier IQ gains, Americans have gained about 22 points over the 70 years between 1932 and 2002. Comparing the new WISC-IV (2002) and the old WISC-III (1989) shows a difference of only 2.5 points. However, they have only five subtests in common when full scale IQ is calculated. If one simulates a comparison of the WISC-III and WISC-IV standardization samples on the 10 subtests of the WISC-III, IQ gains over the intervening 12.75 years were no less than 3.83 points, yielding a minimum estimate of 0.300 points per year. Finally, WISC subtest trends taken in conjunction with "the Nation's Report Card" (NAEP test trends) provide a fascinating picture of the evolution of cognitive skills in America over the last two generations.