Integrated buying model: A model is used by the buyer organization in making purchasing decisions; buying the right material at an acceptable cost and quality level within a reasonable lead time. Acceptable levels of cost and quality: The acceptable levels will vary depending on the firm's competitive position. The decision maker has to contend not only with multiple goals but also with several constraints. Firms often have limited resources. Inventory budgets may be limited, or storage space may constrain the quantity that may be purchased at any instant. The multiple goals must be satisfied within the constraints