An Introduction to Categorical Data Analysis

Log-linear methods provide a powerful framework and the statistical apparatus for rigorously analyzing categorical data. These methods were introduced and developed by Leo Goodman and others in the early 1970s. In the late 1970s and the early 1980s, Goodman, Alan Agresti, Clifford Clogg, Otis Dudley Duncan, and others showed how these models could help us to estimate associations between discrete variables, including ordered and unordered polytomies. The last decade has witnessed a set of diverse extensions of these techniques. This paper reviews the basic log-linear strategy and illustrates key concepts. Citations are given to other articles on these topics, many of which are nontechnical and contain substantive sociological applications.