Which statement correctly defines reliability?

Which statement correctly defines reliability?

• A. The index yields consistent results across examiners.
• B. The index measures what it is intended to measure.
• C. The data can be recorded numerically.
• D. The index can detect small changes in health status.

Answer: (A)

Reliability means that a measurement stays consistent across different administrators or occasions. When an index yields the same results no matter who administers it, that shows high inter-examiner reliability. This is exactly what the statement describes—consistency across examiners. By comparison, validity is about whether the index measures what it’s supposed to measure, which is not the same as consistency. Simply being able to record data numerically doesn’t address how repeatable the results are, and detecting small changes in health status relates more to sensitivity or responsiveness than reliability.

Reliability means that a measurement stays consistent across different administrators or occasions. When an index yields the same results no matter who administers it, that shows high inter-examiner reliability. This is exactly what the statement describes—consistency across examiners.

By comparison, validity is about whether the index measures what it’s supposed to measure, which is not the same as consistency. Simply being able to record data numerically doesn’t address how repeatable the results are, and detecting small changes in health status relates more to sensitivity or responsiveness than reliability.