績效考評是組織掌握內部狀態與激勵人員的重要管理工具。在進行考評時，所採用的評分方式與計算方法會直接影響評比結果，進而影響考評目的之達成。採用語意變數進行考核，因較貼近人們的思維與習慣，而有較容易施行、較容易理解與較富有彈性的優點。然而，這樣的考評方式會使計算過程變得較為繁複。本文就在探討以語意變數進行績效考評時，如何利用凸和與模糊加權平均計算受考核者的整體績效評估值，並達到降低計算複雜度與符合評比效度上之要求。

Performance appraisal is an important management tool for the organization to grasp the internal state and motivate the personnel. In the evaluation, the scoring and calculation methods will directly affect the results of the evaluation, and then affect the achievement of the purpose. Using linguistic variables to evaluate, because more close to people's thinking and habits, has the advantages of easier to implement, easier to understand and more flexible. However, this method of evaluation will make the calculation process more complicated. In this paper, we discuss how to use the convex sum and the fuzzy weighted average to calculate the overall performance value, and to reduce the computational complexity and match the validity requirement of the appraisal.