Inexperienced therapists should not treat sex offenders, because these offenders seldom seek assistance voluntarily and are far better at manipulation and deceit than many therapists can comprehend. Therapists must be skilled at using assessment methods and should not rely on a single method of assessment. In addition, they must bring to light the hidden agendas of the client and uncover information that may have been suppressed by referral sources. They should also recognize that without the use of the polygraph and the plethysmograph, offenders rarely admit the chronicity of their problems, the number of victims, or the various types of deviant behavior. The most effective treatment programs combine behavioral and cognitive approaches and use four main components of therapy: aversive conditioning, skills training, cognitive restructuring, and relapse prevention. Treatment clients may display resistance, break rules, or make no effort to change. In addition, offenders often try to drop out, change therapists, or move to a different State. List of men's group rules used by The Center for Behavioral Intervention in Oregon and 13 references.