Capacity planning is a concept familiar to most students and practitioners of operations research and management science. Davis et al. (2005) define capacity planning as the process of specifying a level of capacity necessary to meet market demands in a cost-efficient way. Capacity planning activities are generally classified according to time frame: long-term (strategic), intermediate (tactical), or short-term (operational). In a traditional manufacturing environment, capacity planning is assumed to take place a·er a facility location decision has been made (Where should we place our factory?) and product forecasting has been completed (How many products or services do we anticipate selling or delivering over the planning horizon?), and serves as an important step in the creation of a production plan. At the strategic level, capacity planning decisions largely revolve around capacity expansion or capital equipment purchases, though decisions regarding out-sourcing and make-versus-buy are common. At the tactical level, capacity planning decisions are closely tied with the aggregate planning process. Ÿe function of aggregate planning is to assign resources to a product or service forecast to create a time-staged plan for meeting demand. Master production scheduling (MPS) and rough-cut capacity planning (RCCP) exercises are usual activities for medium-term capacity planning in a manufacturing environment. Tactical capacity decisions typically include decisions to modify capacity to meet demand through hiring or layoffs, subcontracting, or building to inventory. At the operational level, capacity planning decisions involve activities to formalize and finalize the production plan set by the tactical level plan. Short-term capacity planning activities include materials requirement planning (MRP), capacity requirements planning (CRP) or capacity scheduling, final assembly scheduling, input/output planning control, production activity control, and purchase planning and control (Davis et al., 2005).