A typology is a multidimensional classification. The study of typological procedures is impeded by the use of a plethora of terms, some of which are used interchangeably. "Classification" can be defined as the grouping of entities on the basis of similarity. For example, humans can be classified into female and male. A related term is "taxonomy." According to Simpson (1961, p. 11), taxonomy "is the theoretical study of classification, including its bases, principles, procedures, and rules." Interestingly, the term "classification" has two meanings: One can speak of both the process of classification and its end product, a classification. The terms "classification," "typology," and "taxonomy" are all used widely and somewhat interchangeably in sociology.

Any classification must be mutually exclusive and exhaustive. This requires that there be only one cell for each case. For example, if humans are being classified by sex, this requires that every case be placed in a...