Which statement is true regarding reliability and validity?

Which statement is true regarding reliability and validity?

• A. A measure can be reliable but not valid
• B. A measure cannot be reliable without validity
• C. Validity implies reliability
• D. Reliability implies validity only in experimental designs

Answer: (A)

Reliability is about consistency: a measurement yields the same results across time, across raters, or across items if the construct is stable. Validity is about accuracy: does the measure actually capture what it’s intended to measure? It’s perfectly possible for a tool to be reliable yet not valid. For example, a bathroom scale that always reads two pounds higher than true weight is consistently off in the same way, so it’s reliable but not valid for measuring true weight. That’s why the statement reflecting reliability without validity is true. The other options miss this key distinction. You can have a reliable measure that isn’t valid, so reliability doesn’t depend on validity being present. The idea that validity automatically implies reliability isn’t a universal rule, and reliability isn’t confined to experimental designs—these relationships apply to measurement in general, not just experiments.

Reliability is about consistency: a measurement yields the same results across time, across raters, or across items if the construct is stable. Validity is about accuracy: does the measure actually capture what it’s intended to measure? It’s perfectly possible for a tool to be reliable yet not valid. For example, a bathroom scale that always reads two pounds higher than true weight is consistently off in the same way, so it’s reliable but not valid for measuring true weight. That’s why the statement reflecting reliability without validity is true.

The other options miss this key distinction. You can have a reliable measure that isn’t valid, so reliability doesn’t depend on validity being present. The idea that validity automatically implies reliability isn’t a universal rule, and reliability isn’t confined to experimental designs—these relationships apply to measurement in general, not just experiments.