This session explored the first two years of the evaluation of the Office of Juvenile Justice and Delinquency Prevention(OJJDP)'s Mentoring Enhancement Demonstration Program (MEDP). MEDP funds 10 collaborative grantees encompassing 32 mentoring agencies nationwide. The American Institutes for Research's evaluation of MEDP involves a randomized control trial of 2,400 mentor-mentee matches to assess the agencies' implementation of enhancements to mentoring and the outcomes for the youth served. The panel discussed how the evaluation's complexity has required flexibility from OJJDP, the mentoring agencies, and the evaluators to adopt an evaluation design that is sensitive to local needs and capacities while maintaining fidelity to the evaluation plan. It highlighted the use of a web-based data collection system (REDCap)for large-scale data collection, management, and reporting. It will also highlight the partnership between the evaluators and the mentoring agencies to increase response rates of the data collected from study's mentors, youth, and family members.#2014Conference #Cluster,Multi-SiteandMulti-LevelEval