[Empirical studies of the long-term stability of test norms]

Investigation of the long-term stability of psychological efficiency standards using a frequently applied intelligence test (Hawie -verbalpart). The test value distribution of two representative random tests of adults (from the beginning of 1950 in the FRG and from 1980 to 1983 in the GDR) was investigated and a comparison made together. Significant efficiency differences between the two random tests indicate defective long-term stability of test standards and the necessity to restandardize after 20 to 30 years. Because of significant differences between the old and new standard values and the high percentage of errors (26%), in classifying intelligence when applying the old standard values, the application of the new standards in the clinical diagnosis of intelligence is to be recommended.