Decisions on inventory strategy and rules of engagement are the main procedural drivers for master scheduling. This is not where the job stops, however. In fact, there is a lot more to discuss when viewing master scheduling in its entirety. The master schedule is the set of marching orders for the operations side of the business. It is the drumbeat that determines rates and rhythms for each product line. Information is constantly being fed to the schedule. It comes from forecast changes, the Friday demand review, surprise orders, process variation like scrap or rejects, and it can even come from top management priority changes. That makes schedule maintenance a major effort and focus for the best master schedulers.

Maintaining the master schedule means also managing changes to a minimum. In most organizations, change can affect cost, and too much change can create chaos. In one business I worked with that made household products, one popular option consisted of a stainless-steel outer shell. At the time, stainless steel was in high demand throughout the world. China had entered this particular manufacturing market in a big way, and as a result, shortages of stainless steel developed. This put a significant schedule maintenance issue on the master scheduler. Stainless steel allocation in this particular instance meant that knowing how much material would be available would be possible only a few days prior to delivery. Since this plant was a high-volume operation with many other components, constant juggling of the...