The supposed identity of the evaluative factor of the semantic differential with another measure of attitude, a Guttman scale, is discussed and empirically investigated. Theoretical considerations suggest that the degree of association observed may vary, according to the operation of a number of factors relating to the content and form of constructed scales. An empirical investigation, based on the responses of 1008 subjects, to the concept OBEDIENCE, and to a comparable Guttman scale, is reported. The degree of association found, C = 0.41, did not permit the postulation of a relationship of near identity between the two measures.