Test re-test reliability
Test re-test reliability is a way to measure the consistency of a test over time and therefore the reliability of using it. It is used to ensure that the same test measures the correct variables consistently rather than being affected by external variables. It is calculated by conducting the test twice over a period of time to the same group. Results from both instances of the test are then correlated to evaluate the test's stability over time. This measure is particularly important when creating tests for longitudinal studies.