Testing order review and release mechanisms to improve flow time: a multi-method approach

For decades, various improvements in shop floor performance due to work load control (WLC) and order review and release (ORR) systems have been reported. The majority of these studies rely only on computer simulation to demonstrate their benefits, which typically include minimising resource idleness or order tardiness, among others. However, the vast majority of these studies do not test these mechanisms in real-world shops, thus limiting the research in this area. Using the 'theory-practice iterative cycle', this study employs a combination of case study, computer simulation, and action-research to develop and empirically test a new ORR mechanism that improves mean system flow time (MST) through shortest setups (SSU). This is important because extant simulation studies do not support the proposition that ORR improves MST. The SSU mechanism led to improvements in MST of 25% in simulation studies and 7% in a real-world firm, among other benefits. Additionally, we discuss a number of issues related to field research in ORR that may benefit researchers working on completing the theory-practice cycle.