This article aims to promote a better understanding of the nature of measurement, the special problems posed by measurement in the social sciences, and the inevitable limitations on inferences in science (so that results are not overinterpreted), by using the measurement of blood pressure as an example. As it is necessary to raise questions about the meaning and extent of the validity of something as common as measured blood pressure, even more serious questions are unavoidable in relation to other commonly used measures in social science. The central issue is the validity of the inferences about the construct rather than the validity of the measure per se.
It is important to consider the definition and validity of the construct at issue as well as the adequacy of its representation in the measurement instrument. By considering a particular construct within the context of a conceptual model, researchers and clinicians will improve their understanding of the construct's validity as measured.