An aspect of construct validity, in which measures of constructs that theoretically should not be related to each other are shown, in fact, not to be related to each other (i.e., you should be able to discriminate between dissimilar constructs). Together with convergent validity it provides evidence of construct validity. Thus, neither alone is sufficient to establish construct validity. The use of discriminant validity (and convergent validity) dates from 1959, the year it was introduced by Donald T. Campbell (1916-1996) and Donald W. Fiske (1916-2003) in the most cited paper ever published in the journal Psychological Bulletin. In the same paper, they presented the multitrait-multimethod matrix as a method of interpreting construct validity with reference to both convergent and discriminant validity. Another approach is by means of factor analysis.
See Confirmatory factor analysis, Construct validity, Convergent validity, External validity, Factor analysis, Internal validity, Multitrait-multimethod matrix, Validity