Reliability in psychological measurement refers to the consistency or stability of a measure. Which two forms are the primary forms used in clinical assessment?

• A. Test-retest reliability and inter-rater/internal consistency reliability
• B. Validity and reliability
• C. Criterion validity and predictive validity
• D. Face validity and construct validity

Answer: (A)

Reliability measures how consistently a tool assesses a construct. In clinical assessment, the key forms focus on stability over time and consistency across raters or items. Test-retest reliability examines whether scores stay similar when the same person completes the measure on separate occasions, assuming no real change in the underlying condition. Inter-rater reliability checks that different clinicians or raters yield similar scores for the same behavior, ensuring objective judgment, while internal consistency reliability looks at whether the items within the test all tap into the same construct and cohere as a single scale. When both stability over time and agreement across raters/items are demonstrated, the measure provides dependable results in typical clinical use. Other options describe validity—whether the test measures what it’s supposed to measure—which is a different property from reliability.