Which concept refers to the consistency of test results over time or across equivalent forms?

• A. Reliability
• B. Validity
• C. Construct Validity
• D. Predictive Validity

Answer: (A)

Reliability means the consistency of test results across time or across equivalent forms. It covers ideas like giving the same test twice to the same people and seeing stable scores (test-retest), using different but equivalent versions and getting similar results (parallel-forms), or checking that items on a test hang together to measure the same thing (internal consistency). High reliability reduces measurement error, so scores aren’t flipping around due to chance. It’s essential for any measurement, but it’s not the same as validity—the extent to which the test measures what it’s supposed to measure. The other terms describe validity, not consistency: validity asks whether the inferences from the test are sound; construct validity looks at whether the test relates to theoretical concepts as expected; predictive validity concerns how well test scores predict future outcomes.