An integrated rough number-based approach to design concept evaluation under subjective environments

This study aims at improving the quality and effectiveness of concept evaluation in the early phases of new product development. New product concept evaluation has long been recognised as one of the most crucial decisions for the success of product development, because it has significant impact on the downstream development activities. However, evaluating new product concept is a process involving subjectivity and vagueness. In order to manipulate this problem, a novel decision approach for selecting more rational new product concepts is proposed. Basically, two stages of evaluation process are described: the computation of evaluation criteria weights for new product alternatives and the selection of the most appropriate concept. These stages are composed of a hybrid approach based on a rough group analytic hierarchy process (AHP) method and a rough group technique for order of preference by similarity to ideal solution (TOPSIS) method. The novel approach integrates the strength of rough number in handling vagueness, the advantage of AHP in hierarchy evaluation and the merit of TOPSIS in modelling multi-criteria decision-making. Finally, an application in mini-fridge concept evaluation is given to demonstrate the potential of the methodology.