Guttman's facet theory is described as a method for quantifying information concerning attitudes. It is stated that attitude items are not negatively correlated for usual populations. An attitude is defined as a delimited totality of behavior with respect to something and its components are elements of a set. The first step in facet research design is the development of a rationale. The second step is the selection of the elements in the set. Quantifying is done by mapping the elements of the set into a Cartesian space representing the rules for classification and by rank ordering according to the number of positive facet elements. Rules are given for rank ordering item content. By combining content ordering with the ordering of attitude-behavior levels, several attitude scales have been developed. The use of this method provides a basis for predicting that the correlation matrix for these attitude scales will form a simplex. There are three important aspects of facet design--methodological, theoretical, and applied. (Author/CTM)