Implications of short-term retest effects for the interpretation of longitudinal change.

Although within-person comparisons allow direct assessments of change, some of the observed change may reflect effects associated with prior test experience rather than the processes of primary interest. One method that might allow retest effects to be distinguished from other influences of change involves comparing the pattern of results in a longitudinal study with those in a study with a very short retest interval. Three short-term retest studies with moderately large samples of adults are used to provide this type of reference information about the magnitude of change, test-retest correlations, reliabilities of change, and correlations of the change in different cognitive variables with each other, and with other types of variables.