Limitations of the House of Quality to provide quantitative design information

The House of Quality (HoQ) is a popular design tool that supports information processing and decision making in the engineering design process. While its application is an aid to conceptual aspects of the design process, its use as a quantitative information tool in engineering design is potentially flawed. This flaw is a result of potential designer interpretation of the HoQ results – interpretation which is invalid given the assumptions and information sources behind the HoQ – and is viewed as a critical limitation on the results of the method which can lead to potentially invalid and/or poor decisions. In this paper this limitation and its implications are explored both experimentally and through simulated application.

The approach taken in this research is to first study the HoQ through a “digital experiment” in order to identify the key factors that drive the quantitative results within the tool. Based on the results of the experiment, an example HoQ for a hair dryer is used to empirically study the resulting dangers of the quantitative information which results from the HoQ.

Through this research study of the HoQ, it is determined that while the tool offers conceptual support to the design process, the quantitative information that results is largely invalid.

For the research community the results in this paper create motivation for continued improvement of the HoQ tool from a conceptual, qualitative design aid to a sound quantitative tool. The results indicate exactly where the methodology must be improved.

For users of QFD, specifically the HoQ, the results of this research provide evidence to the limitations of the tool in providing quantitative information for design.