Theory of Constraints Handbook - James Cox Iii [454]
Findings and Recommendations
There is seemingly ample evidence of how diverse issues and problems can be tackled effectively using a variety of Goldratt’s TOC tools, principles, and methods—from the simplistic product mix algorithm, the 5FS, Drum-Buffer-Rope (DBR), Buffer Management (BM), Critical Chain (CC), the EC, to the suite of TP (Rahman, 1998; Kim et al., 2008; Mabin and Balderstone, 2000; 2003; Mabin and Davies, 2003; Inman et al., 2009; Watson et al., 2007).
The review of Kim et al. (2008), reported here, revealed specific publication and research gaps, and some common future research topics and approaches have emerged. First, no work has been published that relates to critical success factors or necessary conditions underpinning the effective implementation of the TP. Given the empirical importance of measuring and comparing the rate of success or failure with other business improvement approaches, such as ERP, Lean, or Six Sigma, it is a little surprising that the publication of research on this topic has attracted minimal attention among TP academics. Further investigation of critical success factors and common problems in the application of the TP is definitely required.
Second, in order to provide practitioners and academics with a critical evaluation of TP tools-in-use, the lack of published empirical work on the effectiveness of TP applications must be addressed. Inman et al.’s (2009) cross-sectional analysis, using structural equation modeling, to examine the links between elements of TOC use, TOC outcomes, and organizational performance has provided illustration of analysis not previously attempted, as a means of filling such gaps. Further empirical studies of both cross-sectional and longitudinal nature, across industries and applications, and over time, would be appropriate, in as much as they would promote the testing of research hypotheses and would strengthen the TP knowledge base. In particular, such research could be directed toward identifying and measuring performance before and after TOC implementation.
Third, the literature reveals an ongoing discussion and critique regarding the philosophical underpinnings of TOC as a methodology. One apparent limitation with the use of the TP is that their use appears to be problem driven; they are applied only when there is a “problem” (Tanner and Honeycutt, 1996; Antunes et al., 2004). The review suggests that there is an unmet need for studies exploring how TOC methods can be applied, not just in problem situations, but also in situations that are problematic in a positive rather than a negative sense. This approach reflects a paradigm shift that has been termed “‘blue ocean” strategy. Kim and Mauborgne (2005) argue that most companies need to create blue oceans of opportunities. They show how a company can create a blue ocean by changing its strategic thinking and using a systems approach. As such, Kim et al. (2008) recommended that more consideration should be given to how the TP could be applied in situations where positives are renewed and advanced, rather than just responding to negatives, or to a need to eliminate or ameliorate problems. The recent development of S&T and their application in situations where “stretch” strategic goals may be set, either to ameliorate or eliminate negatives or to pursue positives, would appear to address this gap. S&T trees were not found in the peer-reviewed literature, but are discussed in Chapters 15, 18, 22, 25, 31, and 34 in this volume.
Furthermore, the overview presented here suggests that there is scope for building on the considerable work that uses the non-TP part of TOC, to test the impact of using the TP in addition or as an alternative to the non-TP tools. Many non-TP examples were documented in Mabin and Balderstone (2000), while a recent example, Pirasteh