What is the difference between reliability and validity in HPFW program evaluation?

• A. They are the same
• B. Reliability is consistency; validity is whether the measure actually assesses the intended construct
• C. Validity is consistency; reliability is accuracy
• D. Reliability is validity inverted

Answer: (B)

The main idea here is understanding how we judge a measure used in HPFW program evaluation. Reliability is about consistency. A reliable instrument gives similar results on repeated trials, under similar conditions, whether you’re looking at test scores over time, across items within a test, or across different evaluators. Validity, on the other hand, asks whether the instrument actually measures the thing it’s meant to measure. In HPFW terms, that means the tool genuinely reflects the construct you intend—such as knowledge of physical activity guidelines, health behaviors, or fitness concepts—and not something else.

It’s possible to have a measure that is highly reliable but not valid: it yields stable, repeatable results but those results don’t reflect the intended construct (for example, a test that consistently measures reading speed rather than fitness knowledge). Conversely, for a measure to be useful for evaluation, it should be valid, and reliability helps support that validity by ensuring the scores are not erratic.