A systematic approach to quality function deployment with a full illustrative example

This paper presents a systematic and operational approach to quality function deployment (QFD), a customer-driven quality management system for product development. After a comprehensive description of the relevant elements in house of quality (HOQ), the first and most influential phase of the QFD system, a 9-step model is proposed to help build such an HOQ. A number of 9-point scales are developed whose uses could help unify the various measurements in HOQ to avoid arbitrariness. Special attention is paid to the various subjective assessments in the HOQ process, and symmetrical triangular fuzzy numbers (STFNs) are suggested for use to capture the vagueness in people's linguistic assessments. Instead of using the quite subjective sales-point concept, entropy method is introduced to conduct competitive analysis and derive competitive priority ratings. A thorough explanation is given to address the concepts, computations and implementations in the proposed HOQ model, followed by a full example for a fried Chinese vegetable to illustrate step by step all the relevant details with the purpose of facilitating the understanding and application of the QFD process. Two difficult parts omitted from our model, especially the correlation matrices, are discussed in some detail finally, and possible approaches are also suggested to deal with them in a potentially more complete HOQ model. (C) 2004 Elsevier Ltd. All rights reserved.