Engineering characteristics prioritisation in QFD using ordinal scales: a robustness analysis

Quality function deployment (QFD) is a management tool used for the design of new products/services and the related production/supply processes. One of the goals of the method is to translate the customer requirements (CRs) into measurable engineering characteristics (ECs) of the new product/service and prioritise them, basing on their relationships with CRs and the related importances. To this purpose, the current scientific literature encompasses several alternative approaches (the most used is the independent scoring method – ISM), in most of which cardinal properties are arbitrarily attributed to data collected on ordinal scales. This paper describes and discusses a new approach based on ME-MCDM (multi expert/multiple criteria decision making) techniques, which do not require any debatable ordinal to cardinal conversion. The theoretical principles and the robustness of the method are presented and tested through some application examples related to a well-known case study reported in the scientific literature.