The study specifically examined the implementation process and the role of risk/need assessment instruments in decisions about the proper level of supervision in probation and parole situations in Oklahoma, with qualitative data obtained from six Department of Corrections officials through indepth interviews. Attitudes of probation officers toward the risk/need assessment instruments were also evaluated. Findings indicated a generally negative or at least a neutral view toward the instruments, although they were seen as having some value for management and legitimation purposes. Paradoxically, respondents found it hard to envision a probation system without them, and a slight majority believed the probation system was better off with the instruments than with discretionary decisions. In addition, those who had more confidence in the value of the instruments were more likely to believe they were personally effective in reducing recidivism, rehabilitating offenders, and reducing the crime rate. In this sense, the scientific status of risk/need instruments lended perceptual rationality and legitimation to the work of probation officers. 29 references and 3 tables