Developed by Louis Guttman during World War II, Guttman scaling (also known as cumulative scaling, scalogram analysis, or implicational scaling) [Page 1565]is the process of measuring a unidimensional concept based on a rank-ordering system, so that agreement with a statement on the scale measuring the concept implies agreement with the previous, lower ranking statements measuring that concept. It was widely used in attitude research and public opinion research. This entry provides a well-known example as well as steps for developing a Guttman scale; the entry concludes with a discussion of criticisms.