This report examines "whether the principles associated with effective treatments for general offenders (Risk-Need-Responsivity: RNR) also apply to sexual offender treatment" (p. i). Sections following an abstract include: introduction; method; results according to the effects of treatment on recidivism, on adherence to RNR principles, and by year and adherence to RNR principles; and discussion about the implications for treatment providers and for researchers. The largest reductions in recidivism are experienced by programs utilizing RNR.