Question

Research has determined that although no single type of treatment can be identified as the most effective, one feature that seems to characterize programs that consistently reduce offender recidivism is:

Answer 1

The answer is: one feature that seems to characterize programs that consistently reduce offender recidivism is THE QUALITY OF THE PROGRAM'S IMPLEMENTATION.
To prevent an offender to repeat his/her offense, a program must have quality implementation.  The implementation should be consistent, well-funded, fully supported and should be properly manned by skilled individuals.