In a "pull system" of production, work is only done at a particular step in the process if the next step in the process is demanding the work. Enough product is ordered or made to replenish what was just used. This is in contrast to most traditional "push systems" where work is done as long as inputs are available. A pull system is designed to match production quantities with a downstream need. Often this can result in lower inventories than a schedule-based production system. Pull systems are most beneficial in processes with short cycle times and high yields. Some features of effective pull systems are small lot sizes and container quantities, fast set-up times, and minimal rework and scrap.

The concepts, "Match Inventory to Predicted Demand" and "Use Pull Systems," seem to offer two conflicting approaches to optimizing inventory. Matching inventory to predicted demand is most appropriate when cycle times for production or assembly are large. In these situations, it is not acceptable to wait until an order is received to begin production. The use of pull systems is more appropriate when production delays are short. Often these two concepts are combined to develop an optimum inventory strategy.