The program demonstrated a form of professional practice that progressed from a rule-driven focus to one that encouraged significant officer discretion and reflected a cultural change among probation officers, juvenile court judges and the probationers themselves. Following a period of testing the program's limits, youths began to accept the legitimacy of intensive supervision and responded by increased conformity to officers' expectations. Issues involved in effecting a successful innovation included: (1) transition from the old to the new model of supervision; (2) evolution of the program's mission and philosophy; (3) applications of the evolved model; (4) unanticipated conditions affecting program operations; and (5) client responses to the program. A critical period in the program occurred in which there was a breakdown in service delivery, officers apparently had difficulty understanding and adjusting to the new organizational norms implicit in the program's mission, and program goals and philosophy were not articulated clearly by program planners. Nevertheless, over the course of the implementation period, a successful model incorporating social control and rehabilitative elements was developed and stabilized. Tables, references