What does reliability measure in psychological testing?

• A. The validity of inferences drawn from scores
• B. The accuracy of content coverage
• C. The consistency of scores across time, items, or raters
• D. The clarity of test instructions

Answer: (C)

Reliability is about consistency in measurement. A reliable test yields similar scores when the same person is measured under similar conditions, whether across time (test-retest), across items within the test (internal consistency), or across different raters (inter-rater reliability). This focus on stability and dependability distinguishes reliability from validity, which asks whether the test actually measures what it intends to measure; items like content coverage relate to validity, and clear instructions affect administration quality rather than reliability itself.