How can a quantitative analysis of Kano’s model be improved further for better understanding of customer needs?

Kano's model is very effective in classifying different customer requirements into different categories considering their impact on customer satisfaction. Since the analysis of the Kano's model is mostly qualitative, however, S-CR relationship functions were earlier proposed as a quantitative approach, and they were applied to many studies successfully. Although the relationship functions are attractive, they have several limitations. This paper proposes new functions, called S-CR+ relationship functions, to overcome the limitations of the previous relationship functions. Furthermore, the new functions also resolve the contradiction between the traditional definition and graph of Kano attributes. The new and previous relationship functions were compared through two examples to demonstrate the effectiveness of the newly proposed functions. The two examples show that the new functions can successfully be implemented to quantify the relationships between customer satisfaction and CR fulfillment level more accurately.