The Explore Computer Science Research (eCSR) evaluation team has developed an evaluation community of practice with supporting tools to address the challenges of conducting a complex, large multisite project evaluation among semi-formal and informal learning initiatives. The eCSR mission is supporting women in computer science research. The evaluation design incorporates a mixed-methods approach that integrates program evaluation into the applied research of community building initiatives among underserved populations in computer science. The value to the audience will be the presentation of a) a practical model for conducting complex, multi-site evaluation that includes the integration of applied research; b) an overview of the qualitative and quantitative evaluation model; and c) lessons learned from the inaugural year of the national program. Our model is applicable to any multi-site initiative addressing fidelity of implementation, data collection and collective impact measurement. The eCSR evaluation approach is broadly applicable across the practice of evaluation.