The study arose from awareness that treatment organizations providing the same services may differ on a host of dimensions which affect the agency's impact on clients. A further motivation was the fact that the rehabilitation philosophy for juvenile offenders has emphasized the importance of keeping children out of detention centers and institutions and has led to the creation of diverse organizations providing community-based services. The study data came from juvenile offenders receiving services from 29 agencies in three sites of the DSO program. The outcome variable was recidivism. The client variables included prior arrests, sex, age, race, and number of services assigned at the point of entry into the program. The analyses of these data showed that much can be learned from an inquiry into agency effects before examining any specific agency properties. For example, agencies made a small but significant contribution to the variation in client recidivism, and agency effects did not interact with client effects in determining rates of rearrest. Further analysis of agency properties focused on the average record of clients in an agency, the numbers of services provided, the amount of contact the agency's staff reported having with the police, and client backgrounds. The analysis suggested that agency characteristics may be important factors in deterrence. In contrast to traditional evaluation designs which only make comparisons across program categories, methodologies for assessing organizational effects permit a far more comprehensive examination of the problem of measuring organizational effectiveness in the human services. Tables, notes, an appendix discussing the computation of variance components, and a list of 40 references are provided.