PracticeEffekte

PracticeEffekte, often translated as practice effects or retest effects, denote systematic improvements in performance on a task that arise from prior exposure to the same or similar tasks, rather than from changes in the underlying trait being measured. The phenomenon is observed across cognitive, motor, and perceptual tasks and is consequential in educational assessments, neuropsychological testing, and longitudinal research.

Causes of practice effects include procedural or strategy learning, reduced task anxiety, increased familiarity with test formats, and adjustments in response criteria. As people repeat tasks, they may develop more efficient strategies, anticipate item types, or settle into more optimal pacing, all contributing to faster and more accurate responses. The magnitude of practice effects varies with task difficulty, participant age, and the interval between testing sessions, and can interact with ceiling or floor effects.

Impact on research and testing is substantial. Practice effects can inflate apparent improvements, confound interpretations of cognitive decline or growth, and threaten the internal validity of longitudinal studies. They can also bias comparisons across groups if repetition is unevenly distributed.

Mitigation and experimental design strategies include using alternate forms of tests, counterbalancing item order, randomizing test versions, increasing the interval between assessments, and employing control groups. Statistical approaches, such as modeling practice effects as a separate component in growth models, can help separate true change from retest improvement.

Examples of practice effects appear in memory recall tasks, where repeated exposure to lists improves performance, in speeded reaction-time tasks, where responses become faster, and in IQ testing, where small but reliable retest gains are observed. Related concepts include retest learning and testing schedule effects.