One principle of effective intervention is that services should be intensive and behavioral in nature. The behavioral programs should target the criminogenic needs of high-risk offenders; and characteristics of offenders, therapists, and programs should be matched. The principle of responsivity states that treatment programs should be delivered in a manner that facilitates the learning of new prosocial skills by the offender. Another principle states that program contingencies and behavioral strategies should be enforced in a firm but fair manner. Also, therapists should relate to offenders in interpersonally sensitive and constructive ways and should be trained and supervised appropriately. Program structure and activities should be designed to disrupt the delinquency network by placing offenders in situations (people and places) where prosocial activities predominate. Relapse prevention strategies should be provided in the community to the extent possible, and a high level of advocacy and brokerage should be attempted as long as community agencies offer appropriate services. Ineffective principles include traditional "Freudian" psychodynamic and "Rogerian" nondirective or client-centered therapies, "medical model" approaches, subcultural and labeling approaches, programs that target low-risk offenders, programs that target offender need factors that are weak predictors of criminal behavior, and "punishing smarter" strategies.