The consistency of a test’s results over repeated administrations is its

Reliability refers to the consistency and stability of a test's results over repeated administrations or under different conditions. A reliable test will produce similar scores for the same individual when administered multiple times, assuming no real change in the trait being measured. For instance, if a student takes a reliable test today and then again next week, their scores should be very close, indicating that the test is consistently measuring the same construct. Reliability is crucial because it ensures that the test scores are dependable and free from excessive random error. While a test must be reliable to be valid, reliability alone does not guarantee validity; a test can consistently measure something incorrectly. Various methods are used to estimate reliability, such as test-retest reliability, parallel forms reliability, and internal consistency reliability. Ensuring reliability is a key step in developing high-quality assessments that provide trustworthy information about student performance.