This paper discusses current issues in theory-driven evaluation from the perspective of the evaluation practice literature. Applications of theory-driven approaches are not easily found, in part, because there are few procedures for conducting them. I offer confirmatory program evaluation as one way to use theory, in combination with quantitative analytical techniques, to assess the effects of social and educational programs. In contrast to many other approaches, theory-driven evaluation generally emphasizes the explication and testing of a priori program theories in determining effectiveness. Confirmatory program evaluation is an impact assessment that examines the pattern of empirical findings against several causal criteria, including temporality, size, gradient (dosage/response), specificity, consistency, and coherence of the program-outcome relationship. A special emphasis is given to identifying causal mechanisms or active ingredients of programs that yield effects. An illustration of confirmatory program evaluation is provided for a child development intervention called the Child Parent Center Program. The limitations of this method are discussed, as well as the conditions under which it is most useful.