The availability of quality treatment assessments for offender correctional programs in the United States is limited (Polaschek & Ross, 2010; Singh, Grann & Fazel, 2011). Therefore, a greater focus on the evaluation of assessment is needed to meet the criminogenic needs of offenders completing probation (Bourgon, Bonta, Rugge, Scott, & Yessine, 2010; Cullen & Gilbert, 2013). The researcher’s objective in this quantitative study was to examine the psychometric properties of the Moral Reconation Therapy Group Member Evaluation (MRT GME), an instrument designed to measure the fidelity of Moral Reconation Therapy (MRT) treatment for offenders on probation. The validity, evidence, and findings were based on the analyses of a secondary data set using 227 scores of offenders who received MRT group therapy while participating in a federal probation pre-trial services treatment program in a Midwestern state. The psychometric properties of a 26-item “receipt of MRT” treatment scale and scores from a 3-item “self-efficacy” instrument were tested. The “receipt of treatment” scale had an internal consistency reliability (alpha) of .96, and the 3-item scale of self-efficacy had an internal consistency reliability (alpha) of .57. There was evidence of construct validity of the sample scores by utilizing factor analysis. Analysis utilizing the Varimax rotation of the data identified four factors: assessment of self, positive relationships, current relationships, and positive identity. The results of the analysis indicated that the MRT GME and the Self-Efficacy scales correlated positively and explained 68.1% of the variance. Recommended changes to the instrument included adding and revising scale items and incorporating multicultural components into the scale. Limitations of the research, implications, and recommendations for future research regarding fidelity of MRT and implementation of other offender treatment program suggestions regarding fidelity are discussed.