Construct validity refers to the totality of evidence about whether a particular operationalisation of a construct adequately represents what is intended by the theoretical account of the construct being measured.
Construct validity includes empirical and theoretical support for the interpretation of the construct. Lines of evidence include statistical analyses of the internal structure of the test (including factor analysis and internal consistency) and correspondence between the test measure and the target construct as judged by experts (content validity).
Construct validity is not distinct from the support for the substantive theory of the construct that the test is designed to measure. There are two main approaches to construct validity:
- Convergent validity: Degree to which a measure is correlated with other measures that it is theoretically predicted to correlate with.
- Discriminant validity: Degree to which the operationalisation does not correlate with other operationalisations that it theoretically should not correlate with.