In social science and psychometrics, construct validity refers to whether a scale measures or correlates with a theorized psychological construct (such as "fluid intelligence"). It is related to the theoretical ideas behind the personality trait under consideration; a non-existent concept in the physical sense may be suggested as a method of organising how personality can be viewed.^[1] The unobservable idea of a unidimensional easier-to-harder dimension must be "constructed" in the words of human language and graphics.

Convergent validity is the degree to which an operation is similar to (converges on) other operations that it theoretically should also be similar to. For instance, to show the convergent validity of a test of mathematics skills, the scores on the test can be correlated with scores on other tests that are also designed to measure basic mathematics ability. High correlations between the test scores would be evidence of a convergent validity.

Discriminant validity describes the degree to which the operationalization is not similar to (diverges from) other operationalizations that it theoretically should not be similar to.

Campbell and Fiske (1959)^[2] introduced the concept of discriminant validity within their discussion on evaluating test validity. They stressed the importance of using both discriminant and convergent validation techniques when assessing new tests. A successful evaluation of discriminant validity shows that a test of a concept is not highly correlated with other tests designed to measure theoretically different concepts.

Nomological validity is a form of construct validity. It is the degree to which a construct behaves as it should within a system of related constructs called a nomological set.