production line. Paper-based information systems and non-integrated computer systems that provide paper or disk outputs result in many information errors, including missing data, redundant data, numerical errors that result from being incorrectly keyed into the system, incorrect calculations based on numerical errors, and bad decisions based on incorrect or old data. In addition, some data is unreliable in non-integrated systems because the same data is categorized differently in the individual databases used by different functional areas. MRPII systems begin with MRP, material requirements planning. MRP allows for the input of sales forecasts from sales and marketing, or of actual sales demand in the form of customers orders. These demands determine the raw materials demand. MRP and MRPII systems draw on a master production schedule, the breakdown of specific plans for each product on a line. While MRP allows for the coordination of raw materials purchasing, MRPII facilitates the development of a detailed production schedule that accounts for machine and labor capacity, scheduling the production runs according to the arrival of materials. An MRPII output is a final labor and machine schedule. Data about the cost of production, including machine time, labor time and materials used, as well as final production numbers, is provided from the MRPII system to accounting and finance. For the companies that want to integrate their other departments with their manufacturing management, ERP software are necessary. Benefits MRP II systems can provide: Better control of inventories Improved scheduling Productive relationships with suppliers For design / engineering: Improved design control Better quality and quality control For financial and costing: Reduced working capital for inventory Improved cash flow through quicker deliveries Accurate inventory records Criticism Authors like Pochet and Wolsey argue that MRP and MRP II, as well as the planning modules in current APS and ERP systems, are actually sets of heuristics. Better production plans could be obtained by optimization over more powerful mathematical programming models, usually integer programming models. While they acknowledge that the use of heuristics, like those prescribed by MRP and MRP II, were necessary in the past due to lack of computational power to solve complex optimization models, this is mitigated to some extent by recent improvements in computers. See also References Computer-aided engineering Enterprise resource planning terminology Business terms Production planning Supply chain management