TOC, lean and six sigma: The missing link to increase productivity?

The objective of this study is to analyze the points of convergence and divergence between the Theory of Constraints, Lean Manufacturing and Six Sigma in an integrated manner when used for continuous improvement of manufacturing systems. This research also aimed to advance a better understanding of the fundamental principles of such methodologies by performing a comparative analysis of critical issues. The focus of discussion of this study was to search the literature to identify characteristics of exclusion and similarities between the three approaches when applied in an integrated way in productive systems. The results of this study suggest that the Theory of Constraints, Lean Manufacturing and Six Sigma have many complementary elements that overlap the divergent points and there is a big space of research to be explored on this issue. As a result, this study presents a critical analysis of 28 comparative criteria relevant to the three approaches. Key words: Theory of constraints, lean manufacturing, six sigma, continuous improvement, manufacturing systems.