Importance-Performance Analysis(IPA) is a well-known methodology to find the area for improvement. However, the IPA uses different strategies depending on an attribute falls in either 'Concentrate', 'Keep up', 'Possible overkill', or Low priority' quadrant. Problems can occur when attributes locate near the demarcation lines. To solve this problem of IPA, I suggest a modified importance-satisfaction analysis which integrates the Slack(1994)'s diagonal approach and Kano's ASC(Jang et al., 2012) into Yang(2003)'s Importance-Satisfaction model. For this, I investigated 21 smartphone's quality attributes, which adopted from Song and Park(2012)'s study, and conducted a survey of 280 university students for the results of Kano' model and the importance and satisfaction of the quality attributes. The results show that the proposed model enables the business managers to prioritize the quality attributes for improvement through the interpretation on the continuous diagonal line using the Kano's questionnaire only, without acquiring any additional survey for importance of attributes. Accordingly, it is expected that the newly proposed method will diminish the limitation of the existing IPA. In addition, to test the validity of the ASC, this study conducts a comparative analysis between the Kano's ASC and Tontini(2007)'s method to determine the relative importance of quality attributes.

The relationship between product quality/function and customer satisfaction has been considered an important point for the new product development. The seminal paper by Kano was the first to thoroughly address the non-linear relationship between product p