Use of several lines of evidence can reduce the inherent ambiguity of evaluation. The techniques for diversifying and bolstering evidence on treatment effects can be grouped into four categories: multiple measures, multiple research designs, multiple analyses, and supplementary data collections. These tactics were used to evaluate a juvenile diversion program affiliated with the Los Angeles County Sheriff's Department. The program provides social services, mainly individual or family counseling, through over 40 community agencies which are on contract to the program. Program goals are to provide a community-based alternative for arrested juveniles who otherwise would have been referred to the juvenile justice system and to reduce juvenile delinquency. To determine whether the program was fulfilling these goals, information was examined on the use of the diversion option by the police, trends in probation referrals, recidivism, and arrest trends. The various measures, research designs, and data stratifications produced convergent results, which indicated that the program had little success in decreasing referrals to the juvenile justice system but produced a positive delinquency reduction effect. Findings suggested that the counseling provided in the program represented a mild treatment which was effective for some juveniles but was insufficient for the older, more experienced delinquents and for whom more intensive services might be needed. Findings also indicated that the state of the art in evaluation research will advance more rapidly if the use of multiple research designs and multiple lines of evidence increases. Tables, notes, and 20 references are provided.