The impact of resource flexibility and staffing decisions on cellular and departmental shop performance

Shop floor control researchers have begun to compare the shop performance advantages of varying forms of resource flexibility. Two major streams of shop floor control research, dual resource constrained shop scheduling (DRC) and group technology (GT), are converging as the literature documents that different forms of resource flexibility aid shop performance in different ways. For example, the DRC literature shows that a small amount of worker flexibility, in the form of cross-training, may be all that is required for superior shop performance. However, the GT literature demonstrates that restricting machines from processing individual part families reduces overall shop effectiveness. Not only does it appear that diverse forms of resource flexibility may be used to alter shop performance in different ways, it may also be that environmental characteristics play a role in arbitrating the performance-improving strength of different forms of flexibility. Studies that have jointly investigated machine and labor flexibility have generated very different conclusions. In this paper we examine the performance advantages of machine and labor flexibility over a wide and realistic set of assumptions and shop floor decisions. We evaluate shop floor control within three different shop configurations at four different levels of staffing. Results indicate that the conclusions of previous studies regarding the choice between labor and machine flexibility are relatively insensitive to a group of labor assignment rules, somewhat more sensitive to changes in demand variability, and very sensitive to staffing levels. Further, this study demonstrates that under several sets of conditions, promoting labor flexibility to the exclusion of machine flexibility provides excellent performance.