Rating the importance of customer needs in quality function deployment by fuzzy and entropy methods

A typical quality function deployment (QFD) consists of four phases. Phase I (sometimes called house of quality), which translates customer needs for a product into technical measures (i.e. product design specifications), can be considered as a nine-step process. A concise and applicable qualitative description and the corresponding quantitative presentation of the first four steps that focus on the customer input are given. Fuzzy and entropy methods are then proposed to obtain the final importance ratings of the customer needs in Step 4. These ratings form the basis for the company to make the product more attractive to customers and thus more competitive. The proposed methods make fuller use of customer input to reveal the relative importance of their needs and are easy to apply. Step 1 is to collect and structure the customer needs. The fuzzy method is used in Step 2 to convert the customers' importance assessments of the needs to fuzzy numbers, and the relative importance ratings of the customer needs are then obtained using fuzzy arithmetic. The entropy method of information theory is used in Step 3 to analyse the customers' assessments of the performance of the company and its related competitors for obtaining the competitive priority ratings of the customer needs. Step 4 combines the two sets of ratings in Step 2 and Step 3 to obtain the final importance ratings of the customer needs. An example is used throughout the paper to illustrate the applications of the proposed methods. It is concluded that the proposed approach shows clearly the consistency of QFD with multiple criteria decision making (MCDM) in determining the relative importance ratings of customer needs, and thus indicates the possibility that the practice-oriented QFD could be built into some existing theoretical frameworks.