Production scheduling theory: Just where is it applicable?

A proliferation of scheduling research has done little to improve production planning practice, despite calls for more comprehensive models. Using a four-factor classification of planning environments (planning level, production type, production strategy, and production cycle time) we show scheduling theory is relevant in few settings. For example, in increasingly common short-cycle environments, where production cycle times are shorter than the planning period, the order in which one processes jobs is seldom important. Moreover, even in long-cycle environments, capacity is seldom fixed, with managers often negotiating for enough capacity to make scheduling fairly easy. Based on extensive consulting experience in Australasia, we call for caution in applying scheduling theory. While complex models are pertinent in some cases, more benefit often arises from establishing appropriate performance measures, planning periods, capacity negotiation processes, and uncertainty reduction measures.