X倍數(Factor X)是一種將產品的價值與產品對環境的衝擊數值化，並進一步的比較出新舊產品的進步比率的方法，可以由倍數的方式輕易的分析出產品本身的進步及對環境衝擊的影響，雖然各公司均開始採用X倍數的方法去計算自家的產品，但是由於各家公司所訂定的X倍數方法不盡相同，只能比較同一家公司的產品，而不同公司的產品將無法相互比較。
本論文先將幾個公司所提出來的較有指標性的方法，做一個整理比較及說明，發現各公司對於環境負載值的計算部份，大多採用Life Cycle Assessment(LCA)生命週期評估方法，且評估的項目差異不大，因此針對差異性較大的產品價值的部份，做進一步的產品收集與分析，包含各公司所採用的產品功能、新舊產品年份與算法，再針對此三部份提出解決的方法，在產品功能的部份使用Quality Function Deployment(QFD)品質機能展開法，將消費者的意見轉化到產品功能上，從中找到權重較高的產品功能；在產品年份的選擇上，有三種選擇方法，第一種是選擇最老的產品，第二種是選擇功能最差的產品，第三種是選擇特定年份的產品；算法的部份，提出兩種不同的算法，第一種是將選出的產品功能包含壽命乘上其各自權重，再做加總，第二種是將產品功能但不包含壽命乘上其各自的權重再加總後，再乘上壽命。
　　接著，將收集到的產品功能資訊套入到以上改良的方法中，實際作運算，即可算出各產品的X倍數。各公司的產品可以透過改良過且統一的X倍數方法得到其產品進步的倍數，使各公司的產品可以互相做比較，且在權重的部份透過QFD方法將消費者的聲音轉化到產品的工程特性上，不再是由公司自行來訂定，較能符合顧客對產品的想法，讓消費者更能比較各公司之產品。

Factor X Indicator Method is an approach to numeric data of product value and the environmental load; hence it also can compare the improvement rate of old and new products by using multiple approaches. Because different companies use different Factor X Indicator Methods to calculate their own products, they can’t compare themselves to other companies.
This research collects, compares and explains some companies’ Factor X Indicator Methods. Most companies use Life Cycle Assessment (LCA) to calculate the environmental loads, hence the items which they use to evaluate don’t have much differences. Therefore, bigger diversification of the same items in different companies pertain product values, the year and calculation of old and new products are collected amd analysed .Also, some methods are proposed to solve the diversifications. First, using Quality Function Deployment (QFD) to turn consumer’s opinions into product value and find the higher index of product value. There are three options of product year choosing: first is choosing the oldest one, second is choosing the worst function one, and the third one is choosing the specific year product. Finally, there are two options of Factor X Indicator calculation. One is multiple product value year to its own index and add all of them, the other is multiple productvalue but not including age to its own index and add all together then multiple age.
Consequently, put all the product information to above proposed methods and we can calculate the Factor X indicator methods of different products. Every company can use the reform method to get the product improvement multiplier, and compare them to different companies. Hence, it is more objective and easier for consumers to compare with all products made by different companies by using QFD for turning consumer’s opinions to product engineering function in index instead of companies using their own approaches.

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