The classification is based on the structural dimensions of program autonomy and horizontal articulation. Thus, it focuses on how the program fits into the correctional organization rather than on the type of service or treatment modality. The four types of programs are (1) "symbolic" programs such as counseling services which have low autonomy and low horizontal articulation; (2) "committed" programs such as comprehensive drug treatment programs which have low autonomy and high horizontal articulation; and (4) interdependent" programs such as non-freestanding therapeutic communities which have high autonomy and high horizontal articulation. The classification system has several important implications for the development, implementation, and probable effectiveness of such programs. In particular, matching the program to the correctional organization is crucial. Chart, notes, and 22 references (Author summary modified)