What is a key component of test-retest reliability?

Test-retest reliability is a measure of the consistency of a test over time. The key component of test-retest reliability lies in comparing the scores that a test taker achieves on the same test conducted at two different times. This helps to determine whether the test produces stable and consistent results, which indicates that the test is reliable. If the scores are similar when taken at different points in time, it demonstrates that the test is measuring a stable characteristic or trait of the individual.

Other components like evaluating score variability between subjects, determining item validity, or correlating multiple tests measuring the same trait are related to different aspects of test development and validation but do not specifically focus on the temporal stability of the test in question. These factors may inform the overall quality and applicability of the test but are not the core of what defines test-retest reliability.