1. Research Background for the Theory of Measurement Diagnostic tests may be divided into: (1) Those constructed on "hunch" and later given some degree of validation against clinical signs, as with the Rorschach, Szondi, etc, and (2) those which are oriented to functional entities—anxiety, schizothyme tendency, etc—previously established by basic source trait research using correlation and computers. The present study investigates the concrete validity in practical clinical situations mainly of the latter type of test. A long series of researches (Cattell, 1950; Cattell et al, 1954; Cattell, 1957; Cattell and Scheier, 1961) has investigated the structure of anxiety and neurotic response patterns in (a) questionnaire, verbal self-report material, and (b) objective, laboratory and miniature-situational tests, henceforth called objective tests. (Both questionnaires and objective tests are "objective" as far as scoring is concerned, ie, they are multiple choice, stencil-scored tests, and therefore fully conspective in scoring.)