Which statement correctly describes test-retest reliability and inter-rater reliability?

• A. Inter-rater reliability is agreement between observers.
• B. Test-retest reliability is consistency over time; inter-rater reliability is agreement between observers.
• C. Test-retest reliability is about different tests; inter-rater reliability is about different raters.
• D. Test-retest reliability measures validity; inter-rater reliability is when the same person rates.

Answer: (B)

Reliability is about consistency in measurement. Test-retest reliability looks at whether scores stay similar over time when the same measure is given to the same people again. If a trait is stable and the test isn’t influenced by memory or practice effects, you’d expect a high correlation between the two administrations. Inter-rater reliability, on the other hand, assesses agreement between different observers or raters scoring the same thing. If two people rating the same behavior or response arrive at the same score, that shows high inter-rater reliability and suggests the scoring is objective and not overly subjective.

So the statement that test-retest reliability is consistency over time and inter-rater reliability is agreement between observers captures both ideas clearly. The other options mix up or incomplete aspects: one only mentions inter-rater reliability without the time-based stability, another misstates what each type measures, and another conflates reliability with validity.