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The WAIS was administered twice, in immediate succession, in standardized fashion, to 35 undergraduate male introductory psychology students. The effects of having just immediately completed the test were reflected in the amount of change in scores from test to retest. On the average, the Verbal IQs increased by 3.1 IQ points and the Performance IQs increased by 14.2 IQ points. Full Scale IQ increased by an average of 8.3 IQ points on retest. Subtests most susceptible to gain on immediate retest were Object Assembly, Picture Arrangement, Digit Symbol, Arithmetic, and Block Design, all of which are timed. Verbal subtests were less affected by prior testing than were Performance subtests. Test-retest reliability coefficients for the Verbal IQ, Performance IQ, and Full Scale IQ were .86, .86, and .88, respectively. Subtest reliabilities ranged from a low of .61 for Object Assembly to a high of .91 for Vocabulary. Retest effects were discussed in terms of previous findings, relevant variables, and the need for further systematic research.
David W. Catron (1978) studied this question.