Which psychometric property refers to the consistency of test results over time?

The concept of reliability pertains to the consistency of test results over time. In psychometrics, this means that if a test is administered multiple times to the same individuals or groups under similar conditions, the results should be similar each time. This consistency can be measured using various methods, including test-retest reliability, where the same test is given to the same group at different times, or inter-rater reliability, which assesses the agreement between different administrators of the test.

Reliability is crucial because it indicates the degree to which a test produces stable and consistent results. Without reliability, a test's results could vary widely, making it difficult to draw meaningful conclusions about the measured constructs or to compare results across different applications of the test.

In contrast, validity refers to how well a test measures what it is supposed to measure, which is a different concept from reliability. Norming involves establishing a baseline of scores for a specific population, while standardization refers to the process of ensuring that a test is administered and scored in a consistent manner. Although these aspects contribute to the overall quality of a test, they do not specifically address the consistency over time that reliability signifies.