TestRetestReliabilität

Test-retest reliability is a measure of the consistency of results from a test administered to the same individuals on two or more occasions under similar conditions. It assesses the extent to which a test yields the same scores when repeated, assuming that the trait or characteristic being measured has not changed significantly between administrations. This type of reliability is particularly important for instruments designed to measure stable attributes, such as personality traits or cognitive abilities.

To determine test-retest reliability, a group of participants completes a test, and then after a suitable interval, they complete the same test again. The scores from the two administrations are then correlated. A high correlation coefficient indicates good test-retest reliability, suggesting that the test provides consistent measurements over time. The length of the interval between test administrations is a crucial factor; too short an interval might lead to participants remembering their previous answers, artificially inflating the reliability, while too long an interval might allow for actual changes in the measured trait, thus reducing the observed reliability.

Low test-retest reliability can arise from various sources, including fluctuations in the individual's state (e.g., fatigue, mood), inconsistencies in test administration, or inherent variability in the construct being measured. When a test exhibits low test-retest reliability, its use for making comparisons or drawing conclusions about stable characteristics is problematic, as the observed scores may not accurately reflect the true underlying attribute.