What is the purpose of split-half reliability in psychological testing?

The purpose of split-half reliability in psychological testing is centered on assessing the internal consistency of a test by comparing the scores from two halves of that same test. This method involves dividing the test into two equal segments and then correlating the scores from each half. If both halves yield similar scores, it indicates that the test is measuring a consistent construct. A high correlation suggests that the items on the test are reliably measuring the same underlying trait, which is crucial for ensuring the credibility of the test results. This reliability estimate helps in understanding whether the test produces stable and consistent results, which is essential for psychological assessment and research.