IQ variability in relation to age on the revised Stanford-Binet

The authors examine the thesis that age differences in variability between the Stanford-Binet age levels are due to sampling errors in the standardization data. Their findings do not support this position. They conclude, on the basis of their data, that such differences are due to factors inherent in the test itself. They therefore recommend that in order to maintain the meaning of the IQ as a uniform index of intelligence, standard scores (T or Z scores being preferred) should be used rather than IQ's themselves. (PsycINFO Database Record (c) 2016 APA, all rights reserved)