A simulation model, driven by real order time series, of an actual make-for-stock shop is described. A broad spectrum of different sets of decision rules has been incorporated in the model in an attempt to represent as many as possible of the production controls which might be utilized by a production manager. Experiments designed to determine the impact on a production cost function of changes in decision rules can be conducted over a wide range of conditions, with the objective of assessing the robustness of rule changes.