METHODOLOGIES AND APPLICATION Mobile phone selection based on a novel quality function deployment approach Burak Efe 1 • Mehmet Akif Yerlikaya 2 • O ¨ mer Faruk Efe 3 Ó Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract Fuzzy quality function deployment (QFD) approach has been extensively implemented to transform customer requirements (CRs) into products or services because fuzzy numbers provide to obtain more accurately the judgments of experts in vagueness environment. This study proposes to use interval type-2 fuzzy (IT2F) numbers in the improving of fuzzy QFD method. The developed IT2F number-based QFD approach utilizes IT2F sets to define the correlations among CRs; the relations between CRs and design requirements (DRs); the correlations among DRs; the weights of DRs. There is no paper about integrating QFD approach and IT2F set in the literature. IT2F numbers include more accurately the judgments of the experts to express the vagueness of the applications. In addition, TOPSIS (technique for order performance by similarity to ideal solution) approach based on interval type-2 trapezoidal fuzzy (IT2TrF) is utilized to select the best mobile phone. Finally, mobile phone selection implementation is handled to indicate the efficiency of the proposed method. Keywords Quality function deployment  New product development  TOPSIS  Interval type-2 fuzzy number  Mobile phone selection 1 Introduction A valuable brand is important for consumers and investors, manufacturers and retailers in the market. Consumers are turning to brands that they believe to provide some value to them. This issue causes that investors invest to these brands and retailers include this brand in their stores. Such brands are also effective in helping to brokerage firms so that retail firms gain a positive image. Thus, a firm with brand value provides benefits for itself and other factors in the market (Gelal 2018). Nowadays, because customers’ desires are higher than the expected, products manufactured to meet customer requirements (CRs) and needs are insufficient to ensure that producers receive the lion share of the market. In particular, in free market economies, companies must constantly develop new products that can respond to mar- ket needs to become permanent and grow in market. In order to satisfy the changing of CRs, developing products using new modern research activities or producing com- pletely new products has become the main of firms in the industries that are based on full competition (S ¸ en 2006). This situation causes to be a more important and necessary step in the improving of novel products in the design phase. New product development (NPD) is handled as one of the important factors of competition. Although new products require effort, time and ability, the cost and risk of failure are still high. For example, a survey showed that the rate of failure in new products was 40% in consumer goods, 20% in industrial goods and 18% in services (S ¸ en 2006). Therefore, firms encounter high risks of reducing their market share advantage in the NPD process (Efe et al. Communicated by V. Loia. & Burak Efe burakefe0642@gmail.com Mehmet Akif Yerlikaya mayerlikaya@beu.edu.tr O ¨ mer Faruk Efe omerfarukefe86@gmail.com 1 Department of Industrial Engineering, Necmettin Erbakan University, Konya, Turkey 2 Department of Industrial Engineering, Bitlis Eren University, Bitlis, Turkey 3 Department of Industrial Products Design, Afyon Kocatepe University, Afyonkarahisar, Turkey 123 Soft Computing https://doi.org/10.1007/s00500-020-04876-x