classification and regression tree analysis: a method of classifying data into successively smaller and more homogeneous subgroups according to a set of predictor variables. CART analysis is similar to but distinct from regression analysis in its homogeneity of case subsets. The results of a CART analysis may be displayed in a diagram resembling a tree—subsets of data, based on values of the outcome variable, are shown to branch off from higher level subsets of data.