The schedule of manufactured items usually created to fill 'outside' demand from forecasts, customer orders and interplant orders that specifies the exact item numbers, dates and quantities for production but is not in itself a production order to be released to the floor. It considers the high-level production plan and rough cut capacity availability, and aligns with management targets for linearity and permissible level of changes. Once accepted, the MPS specifies the date and quantity requirements used by MRP to explode demand through the bill of materials. While most often for end items, variations of MPS allow planning critical lower levels such as major subassemblies based on a forecast that is then consumed by customer orders for finished goods that require those subassemblies. The MPS is the main driver for the rest of the planning and scheduling system, and the level of success in attaining a realistic MPS often indicates how well the other detailed parts of the system function.