The effectiveness of a training provided to school counselors on the implementation of comprehensive school counseling programs based on the ASCA National Model was examined. The data analyzed were the closing the gap summary results reports submitted following training. The reports were used to determine whether those trained could design, implement, and evaluate interventions to close achievement gaps and in what ways, if any, the academic success of students was improved as a result of the implemented interventions. The majority of counselors were able to implement counselor-led interventions and to identify students for whom achievement gaps existed in their schools; however, fewer counselors were able to assess interventions and document changes using both perception and results data, and the majority of reports lacked sufficient detail to fully explain interventions provided and results found. However, despite the ability to assess interventions or write quality results reports, the school counselors impacted student achievement in the areas of test scores, grades, attendance, and discipline/behavior. The findings indicate that counselors can impact student achievement within comprehensive school counseling programs. However, counselors may benefit from additional training in identifying achievement gaps based on data, evaluating outcomes, and reporting findings. At the system level, reporting procedures may need to be revised to obtain complete and accurate information about closing the gap interventions. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]