Using a randomized controlled trial, (one of the most rigorous scientific methods for measuring program effects), the evaluation found that those parolees who participated in New Jersey's seven day reporting centers did not have better recidivism outcomes than parolees under traditional intensive supervision; and during some periods, the participants in day reporting centers had more arrests and fewer jobs. In addition, the day centers cost more than traditional intensive probation. The evaluators caution, however, that these findings should not lead to the conclusion that individual parole supervision alone is sufficient, because the parolees under traditional supervision were assigned additional conditions at the discretion of their parole officers. These additional requirements could include drug treatment, mental health treatment, and education programs. The evaluation, which was sponsored by the National Institute of Justice and the New Jersey State Parole Board, randomly assigned parolees to either a day reporting center program or the traditional parole program. Each group was composed of approximately 200 parolees with similar criminal backgrounds. Recidivism data were collected on participants in both groups for 18 months.