Retest effects in cognitive ability tests: A meta-analysis

Retest effects are referred to as the increase in test scores due to the repeated administration of cognitive ability tests. This meta-analysis attempts to update and extend previous meta-analyses by examining the size of retest effects and its determinants in a high number of cognitive ability tests for up to four test administrations. Strict inclusion and exclusion criteria were applied regarding study design, participant age and health status, and cognitive ability tests. An extensive literature search detected 174 samples from 122 studies, which resulted in 786 test outcomes and an overall sample size of 153,185. A comprehensive longitudinal multilevel meta-analysis revealed significant retest effects and no further score gains after the third test administration. Moderator analyses for multiple retests indicated that cognitive ability operation and content, equivalence of test forms, retest interval and participant age have a significant influence on the size of the retest effect. Implications for future research and retesting practice are discussed.