Which statement best differentiates reliability from validity in educational measurement?

• A. Reliability concerns about the length of a test.
• B. Reliability concerns the consistency of scores across assessments; validity concerns whether the test measures what it intends to measure.
• C. Reliability concerns the accuracy of scoring; validity concerns the speed of test administration.
• D. Reliability concerns scoring speed; Validity concerns scoring accuracy.

Answer: (B)

Reliability is about consistency of measurement across time, items, or raters. When a test yields similar results on repeated administrations, with the same scoring rules, or with different scorers agreeing on scores, it is considered reliable. Validity is about whether the test actually measures the intended attribute—whether the items cover the right content, whether the results correspond to the theoretical construct, and whether the scores predict or relate to relevant outcomes.

In short, reliability checks if the scores are stable and repeatable; validity asks if those scores mean what they are meant to mean. A test can be reliable but not valid if it consistently measures the wrong thing, and a valid test must also be reliable to support trustworthy interpretations.