Comparative research involves the study of two or more societies, for one of two purposes: (1) for establishing the generality of theories, hypotheses, or empirical generalizations already well established for one nation, or (2) for understanding the impact societal properties have on specific social phenomena. Because of problems of inference from samples of social systems that are inherently nonrandom and nonrepresentative, comparative research is not well suited for purely descriptive purposes. Instead, comparative research as a method of studying family life should be used to investigate the utility of explanatory theory.