The program also uses a behavioral level system through which each offender is expected to progress; level I involves minimal cooperation with rules and responsibilities; level II and level III show increased acceptance of rules and responsibilities; and level IV shows a maximum level of adherence to rules and responsibilities. In addition, institution staff psychologists, working with SSOP staff, provide individual and family therapy services. The cottage treatment principle is used, whereby all staff who impact upon the daily life of the offender are trained for and participate in the delivery of treatment services to the offender. Currently SSOP staff includes two full- time social workers, a group facilitator, seven youth counselors, six teachers, and a section manager. Several recent evaluation studies have found sexual recidivism rates of under 10 percent. Recidivism, for the purpose of these studies, has been defined as an SSOP participant's return to either a juvenile or adult institution or to either juvenile or adult probation/parole for a new sexual offense. These rates have remained relatively consistent, even for graduates who have been tracked for over a decade.