A measurement instrument which gives consistent results each time it is used but does not really describe the concept being measured is reliable but not valid.

Question

Quizplus · Accepted Answer

Reliability refers to the consistency of results obtained from a measurement instrument, while validity refers to whether the instrument actually measures the concept it is intended to measure. It is possible for an instrument to be reliable but not valid, meaning that it consistently produces the same results, but those results do not accurately reflect the concept being measured.

A Measurement Instrument Which Gives Consistent Results Each Time It