消費者通常會根據產品的效益，以價格和功能的評比作為決策的參考，這種訴求是理性的。但是另外有一些消費行為卻超越理性，而是以使用者主觀衡量得失之後的認知價值作為決策的關鍵。另一方面，以創意與美學等感性訴求的設計活動，則被視為能夠提昇產品認知價值的關鍵因素。因此，本研究期望能探討設計提昇產品認知價值之情感向度指標及其評價模式，作為改進產品開發與決策品質的重要依據。本研究分為三個階段：第一階段先透過文獻研究及訪談設計師與使用者的方式，找出建立情感向度的15 個元素因子；第二階段則透過159 份有效問卷，進行因素分析並萃取出情感向度的四個構面，並將之命名為費思指標 (FASE Index)；第三階段則以三款經典設計商品，對21 名決策性格不同的受測者進行實驗，結合模糊理論與成對比較矩陣，對受測者費思指標的權值進行評價。最後並藉由卡方分析、G2 統計與四次的二因子變異數分析，檢定費思指標的區別能力與實用性。統計分析結果顯示，受測者面對不同設計款式的產品，在費思指標上具有顯著的感受差異；而某些產品的設計手法，也能使不同決策性格的受測者在費思指標上，呈現不同的感受評價。研究結果顯示，產業將可藉由費思指標作為規劃產品開發策略之依據，除可強化競爭優勢，提昇設計品質外，並可擴展成為生活、商業和公共政策等諸多領域的決策參考。

Often customers make their purchase decision based on price, quality and functionality of the product. However, sometimes, they make the decision based on perceived value. Though design can improve the perceived value of the product, it is not easy for designers to predict the user’s preference and reaction toward their products. The gap between designers and users in the design process is always a challenge that academic and industrial professionals try to overcome. Therefore, an effective decision method is necessary and extremely important to evaluate the design at the early stage of product development. This study extracted the indexes from emotional dimensions and developed an evaluation method for the perceived value of products. Based on literature review and the interview of designers and users, the authors identified 15 emotional variables. Followed by conducting questionnaire survey on 159 participants and factor analysis, four indexes were extracted. They are Features, Association, Social-esteem, and Engagement, also named as FASE index. Then by combining the fuzzy theory and the pair-wise comparison method, an evaluation method for FASE index was developed. At the end, the analysis of perception differences for three classic design products was executed to test the sensitivity of FASE index. The findings of this study have demonstrated that FASE index and the decision method can be used to discriminate among design concepts and improve the design process and quality.