Any variable which has only two categories. In theory these categories are meant to be mutually exclusive. The variable ‘sex’, with its two categories of ‘male’ and ‘female’, is a good example. There are numerous well-known examples of dichotomies in sociology: Tönnies's Gemeinschaft and Gesellschaft, Durkheim's mechanical and organic solidarity, and so on. A variable with more than two categories is called a polytomy. Sometimes, in order to simplify analysis, polytomous variables are collapsed—the number of categories is reduced by merging adjacent codes—to a dichotomy.
Subjects: Philosophy — Sociology.