The U.S. Army uses the Command and General Staff Officer Course (CGSOC) as a key component of its system for developing critical thinking skills and abilities in its officer corps. The Common Core is the first phase of CGSOC. The Common Core is taught in three venues: a resident course taught at Fort Leavenworth and at satellite campuses; Advanced Distributed Learning (ADL), a web-based, self-paced course that uses interactive multimedia instruction; and The Army School System (TASS), primarily for Reserve Component officers, which combines resident and interactive multimedia instruction and is taught by the U.S. Army Reserve Command's 97th Brigade and its three subordinate battalions. CGSOC consists of nine blocks of instruction taught as stand-alone modules in the resident course (14-16 weeks long) and organized into three phases in TASS and ADL (designed to be taken over a period of up to 18 months). In response to the interests of Army leadership, this study sought to answer the following questions about the Common Core, focusing on the 2009-2010 academic year: Based on current methods of evaluation, how effective is the Common Core, and to what extent are there differences among distributed, resident, and mixed-delivery venues? Based on current measures, how can course delivery be improved? How well do current methods of evaluation gauge course success and point to needed improvements? To answer these questions, the authors analyzed available data from Command and General Staff School, including responses to student surveys, grades on assignments, and student characteristics. In addition, the authors conducted a quasi-experimental study to assess consistency in grading among faculty members.