User-satisfaction framework for the development of shoes for the elderly in fuzzy environment

Shoes designed for the elderly can reduce the risk of injury associated with falling. Pinpointing the specific needs of users and directions for product improvement allows companies to maximize the allocation of limited resources. However, user evaluation of important criteria is often ambiguous and uncertain. This paper contributes to solving this issue through the development of a two-stage user-satisfaction framework with a fuzzy-Six Sigma index and fuzzy axiomatic design (FAD). In the proposed method, we consider sampling uncertainty, analyze the vagueness of natural-language evaluations, and explore the match between company capabilities and user satisfaction. This framework highlights both the advantages and disadvantages of current shoe designs for the elderly, and a case study illustrates the applicability of the framework. Additionally, result comparison and sensitivity analysis are conducted to verify the reliability and effectiveness of the proposed method. Finally, the managerial implications, conclusions and limitations of the study are discussed.