Which statement about measurement tools is true?

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Reliability vs validity in measurement tools. Reliability means the measurement yields consistent results across repeated trials or raters. Validity means the instrument actually measures the intended construct or outcome.

An instrument can be highly reliable—giving the same results every time—yet not valid if those results don’t reflect the thing you want to measure. For example, a scale could repeatedly show the same weight for a person, but if the scale is miscalibrated so it’s measuring the wrong quantity, it isn’t valid for assessing true weight. Similarly, a survey can produce consistent scores across administrations but still fail to capture the intended construct if the questions don’t align with what you’re trying to assess.

Importantly, validity depends on accuracy to the intended target, while reliability is about consistency. A measure cannot be valid if it isn’t reliable, but reliability alone does not guarantee validity. So an instrument can be highly reliable but not valid.