A suggested production, purchase or replenishment order generated by an MRP or other planning system to meet a projected shortage against desired safety stock levels. The shortage date becomes the due date, the release date is backward scheduled based on lead time, and the quantity is based on the specified lot size. Planned orders for upper level items create requirements for lower level components, and MRP generations delete existing planned orders and regenerate new ones based on changes in requirements. Planned orders must be firmed or accepted before releasing to production or to a vendor.