These departments are staffed primarily by social workers and have responsibility for about 4,000 persons under supervision, primarily probationers. Inmates are released after serving two-thirds or at least 2 months of their sentences. Release is a purely administrative act -- one which is currently subject to heated debate. In general, release decisions are made locally, are based on whether it is felt the inmate can refrain from committing further crimes during release; and are favorable in 90 percent of cases. In addition, inmates may apply for an early release once half their sentence has been served. In these cases, the decision to release is based on such factors as treatment needs, humanitarian considerations, prior record, and an assessment of the likelihood of relapse. Proposals currently being considered for changing the system include making release on parole compulsory, placing decisionmaking authority in the hands of courts or other independent body, or abolishing parole entirely in favor of a corresponding reduction in sentences.