AbstractThe paper describes a decision-making model to control the entire expenditure by Rolls-Royce Aero Engine Division with outside suppliers. The project began as an“investigation into economic order quantities”, and expanded into an automatic decision-making package for determining the size of orders to be placed on suppliers, the length of time into the future these orders should stretch, the best price break information to ask for, and the extent to which changes in demand within Rolls-Royce should be suppressed to cushion the suppliers from unnecessary fluctuations. A conservative estimate of savings which result from implementing a model of this nature is that the purchase bill is reduced by at least 5 per cent and the inventory by somewhere in the region of 15 per cent.