This chapter is concerned with two related observational methods: simulation and experimentation. As an introduction, consider the following study. Jacob and his colleagues (Jacob & Krahn, 1988; Jacob & Leonard, 1988) were interested in how alcohol consumption in families of alcoholics might influence family interaction, following two hypotheses raised by Steinglass, Tisenko, and Reiss (1985). Steinglass and co-workers argued (1) that intoxication could facilitate certain family interactions and inhibit others in such a way as to provide temporary solutions to chronic family problems, stabilizing an unstable family system; and (2) that this would differ for families where the alcoholic was a steady drinker and alcohol consumption provided an organizing principle to family life compared to families where the alcoholic member drank episodically and the family did not adjust its interaction to accommodate to drinking.