Design for Six Sigma: caveat emptor

PurposeThe purpose of this paper is to describe the historical approach to concurrent engineering (CE) which has resulted in product line management (PLM) and then evaluates the theoretical models that have been proposed for design for Six Sigma (DFSS) in order to determine which model is able to provide the most consistent approach with historical development of PLM.Design/methodology/approachThe approach begins with an overview of the approach taken by the Union of Japanese Scientists and Engineers (JUSE) in the development of a coherent quality methodology for structured analysis and problem solving – the Deming Wheel of plan‐do‐check‐act (PDCA) which has become the standard model in Japanese total quality management to define a logical decomposition in process management. In Japan, PDCA is the single logical model which has been broadly accepted as the construct for understanding how to develop both strategic and operational quality methods. The second step in the approach is to examine a similar American development of the model for statistical problem solving that is applied in the Six Sigma method for statistical problem solving: define‐measure‐analyze‐improve‐control (DMAIC). Next, the paper examines the historical sequence in the way the product development process has developed over the past forty years, with emphasis on its military origins (especially CE) and which resulted in the generic model for PLM. The final part of this paper examines the models that have been proposed to implement DFSS over the past ten years and evaluate their logical congruence with the engineering community's design process.FindingsProblems in alignment with the engineering design process were identified with all of the DFSS models and with the non‐structured or “heuristic” approach to developing a coherent body of knowledge related to DFSS.Originality/valueThis paper provides a challenge to the quality community as well as to the academic community. The paper points out the need for rigorous examination of logical models that are proposed for guiding the thinking of practitioners in the use of quality methods for both the engineering of products and business systems. An expose of lack of rationality in the way an approach to DFSS has been investigated calls for more responsibility in the management of the development of this body of knowledge.