Which aspect does reliability NOT refer to in psychological testing?

Reliability in psychological testing pertains to the consistency and stability of the test results across different administrations and contexts. Therefore, the aspect of clarity of the test items does not relate to reliability. While clarity is essential for a test's validity—ensuring that the test measures what it is intended to measure—it does not directly impact the idea that the test will yield consistent outcomes over time or across different populations.

Reliability encompasses the consistency of measurement over time, ensuring that repeating the test under similar conditions yields similar results, as well as the uniformity of test results, where different items or parts of the test assess the same underlying construct in a stable manner. Comparative analysis among different groups is related to validity and fairness, rather than the reliability of the test itself. Thus, clarity of test items stands apart from the core principles of reliability in psychological testing.