PTP's, like punitive and incapacitative corrections mechanisms, have the ultimate goal of protecting society from criminal behavior. PTP's accomplish this by modifying offender attitudes and developing offender skills through positive incentives as well as by changing offender life circumstances and improving socioeconomic opportunities. PTP's thus increase public protection by reducing the illegal behavior of target groups. Empirical studies of PTP's indicate that their effectiveness depends on (1) the particular treatment approach used, (2) the type of offender target group, and (3) the treatment setting. These findings suggest that future PTP's should be more closely adapted to the life circumstances and personal characteristics of offenders. The CTP, an experiment conducted by the California Youth Authority from 1961 to 1974, involved 802 boys and 212 girls. Based on approximately 10 years of direct observation, routine case documentation, formal discussions, and selected statistical analyses, the CTP was found to reduce significantly the recidivism of participants compared to controls processed in a traditional manner. General implications for PTP's are drawn from the findings. Data charts and tables, 9 notes, and 19 references are included.