A form of factor analysis in which the correlations between individuals rather than tests are analysed. It was introduced by the US-based English psychologist William Stephenson (1902–89) in an article entitled ‘Correlating Persons Instead of Tests’ in the journal Character and Personality in 1935 and expounded at length in his book The Study of Behavior: Q-Technique and its Methodology (1953). Also called Q-technique. See also Q-sort. Compare R-methodology.