本文重新編製以貿易權數為基礎的新台幣實質有效匯率指數，並實證分析其時間數列性質與預測表現。我們發現：(一)該指數的變動，由於市場套利力量存在，只有少部分可由進出口量的變動解釋；與(二)該指數足以預測未來出口量，且預測表現優於大部分其他單位所編製的指數。這些結果顯示我們所編製的實質有效匯率指大致合理並符合編製目的。亦即，如果我們想瞭解進出口競爭力、進出口或貿易收支與有效指數的互動關係。或預測出口量，現行以「貿易權數」為基礎所編製的實質指數都能適用。

　　　　　Real effective exchange rate index is considered an important economic indicator. We re-construct a trade- weighted measure of Taiwan's real effective exchange rate, and examine its time series properties. Our major findings include: (1)variation of changes in export and import, due to the arbitraging mechanism, explains a limited amount of the index variation, and (2)the index demonstrates a superior out-of sample prediction performance to most of the available indices. Thus the trade-weighted index generally serves well as a measure of national competitiveness, and summarizes useful information about trade pattern.