What does reliability refer to in psychological measurement?

What does reliability refer to in psychological measurement?

• A. Consistency of a measure over time
• B. Validity of what it measures
• C. Descriptive statistics adequacy
• D. Sample size representativeness

Answer: (A)

Reliability means consistency in measurement. A measure is reliable when it yields stable, repeatable results under consistent conditions, such as scores that stay the same across repeated testing, measures that hang together coherently across items, or ratings that agree across different raters. This focus on stability over time is what makes consistency of a measure over time the best description. It’s possible for a test to be reliable but not valid, meaning it’s consistently wrong about what it’s supposed to measure. The other concepts touch on accuracy of what’s being measured or on sampling and data summaries, not on the repeatability of the measurement itself.

Reliability means consistency in measurement. A measure is reliable when it yields stable, repeatable results under consistent conditions, such as scores that stay the same across repeated testing, measures that hang together coherently across items, or ratings that agree across different raters. This focus on stability over time is what makes consistency of a measure over time the best description. It’s possible for a test to be reliable but not valid, meaning it’s consistently wrong about what it’s supposed to measure. The other concepts touch on accuracy of what’s being measured or on sampling and data summaries, not on the repeatability of the measurement itself.