In recent years, the RAND National Defense Research Institute has developed a simulation model that is capable of managing hundreds or thousands of officers individually according to complex laws, policies, and practices. The model can address very detailed questions that are not easily answered using spreadsheet models, stock-and-flow models, or linear programming models. The simulation model has been applied to research sponsored by the Office of the Secretary of Defense, the Army, the Navy, and the Air Force. This technical report describes the design of a version of the simulation model that has been adapted specifically to address general and flag officer management subject to provisions of the Duncan Hunter National Defense Authorization Act for Fiscal Year 2009. The report also provides results requested by the Office of the Secretary of Defense, which has sponsored most of the work using different versions of the simulation model.