WAIS-III and WISC-III IQ gains in the United States from 1972 to 1995: How to compensate for obsolete norms

Flynn used data covering 1932 to 1972 to put U.S, gains at about 0.300 IQ points per year. For post-1972, comparison of WISC-R versus WISC-III, particularly the data of Zimmerman and Woo-Sam, gives a rate of 0.312. However, comparison of WAIS-R versus WAIS-III shows that the current rate may be as low as 0.171. It is hypothesized that the discrepancy may be due to sampling error and it is suggested that post-1972 US gains be put at about 0.25 points per year.