本文以資料包絡分析法衡量2004年第一季至2008年第三季台灣商業銀行之效率與生產力，並以其代表銀行之經營績效。不同於過去文獻之處在於本文以前瞻之觀點（沈中華，2005）求出放款預期損失以衡量放款風險，作為放款過程中的非意欲產出。本文並利用Ray and Desli（1997）架構拆解Malmquist總要素生產力指數，探討銀行績效變動之來源，此外，亦將該拆解結果與Färe et al.（1994）拆解方式比較，發現在技術變動部分有明顯不同。本文並探討影響銀行效率之因素以及檢定不同類型銀行之生產力表現是否有顯著差異。 / The purpose of this paper is to examine the efficiency and productivity change of Taiwan’s banks over 2004Q1-2008Q3 using data envelopment analysis. Unlike the literature of the past, this paper uses the forward-looking viewpoint to derive expected losses from loans to measure the credit risk. In addition, the loan expected loss is thought of as an undesirable output in the estimation of efficiency and productivity. On the other hand, this paper uses a VRS frontier benchmark (Ray and Desli, 1997) to analyze the sources of productivity change. This paper also compares this result with that of Färe et al.（1994）decomposition, and finds that the estimated technical changes of two approaches are significantly different. Further, this paper analyzes the factors influencing banks’ efficiency, and investigates the productivity differences between different ownerships.

本文採取隨機方向距離函數方法，探討制度變革前、後(第一次金融改革)對台灣銀行業技術效率的影響。資料期間涵蓋1999年至2012年。相較傳統Shephard距離函數，隨機方向距離函數方法最大優點係可同時考量增加意欲產出、減少投入與非意欲產出。本文依循Koutsomanoli-Filippaki et al. (2009a) 模型，並納入考慮非意欲產出。本文採取隨機邊界法進行實證估計，以最大概似法估計方向距離函數，依據Battese and Coelli (1995)的模型將環境變數納入實證模型 (主要模型)，並考量未包含環境變數之模型，與主要模型比較。此外，為凸顯非意欲產出之重要性，本文亦估計未考慮非意欲產出之模型以及傳統距離函數，以茲比較。 實證結果顯示，考慮非意欲產出與環境變數的主要模型，其估計結果相較其他模型之無效率明顯高估。2002年以前，技術無效率逐漸攀升。一次金改期間，技術無效率明顯下降，證明制度變革下，銀行效率獲得改善。惟2004年後反轉向上，尤其在雙卡風暴與次貸風暴期間，技術無效率明顯惡化。此外，本文將資料分群進行分析，發現公營銀行或是金控銀行較有效率。 / This paper aims to gain further insights into whether the policy of First Financial Restructuring (FFR) does improve the technical efficiency of banks in Taiwan during the period 1999-2012 by using the directional technology distance function (DDF). Compared to the conventional distance function, DDF simultaneously allows for the expansion of the desirables and the contraction of the undesirables. We follow Koutsomanoli-Filippaki et al. (2009a), and differing from them, we include undesirable outputs in DDF to depict a bank’s true production activities. We find on average that the banks have a lower technical inefficiency with the main model compared to the other models. However, prior to 2002, the technical inefficiency exhibits a gradual upward trend and then posts a downward trend during the FFR period. These results suggest that the improved efficiency in the FFR period is possibly due to enhanced banking and benefits obtained from compliance with FFR. After the FFR period, the inefficiency scores deteriorate sharply, especially during the “credit card and cash card crisis” in 2006 and “the subprime mortgage crisis” in 2008. Public banks are more efficient than private banks. Banks belonging to a financial holding company (FHC) may operate more efficiently than those belonging to a non-FHC.

本文以貝氏方法估計方向距離函數，加入單調性與曲度限制，同時考慮環境變數於模型中。為了凸顯考慮非意欲產出方向距離函數的優點，本文同時估計產出面射線距離函數，並與方向距離函數模型比較。實證分析資料為1970至2010年間各國總體經濟變數，分別在有無加入限制條件與環境變數的狀況下，估計兩種距離函數，從無效率值、效率分數與技術進步率等角度分析彼此間的差異。發現射線距離函數模型由於忽略非意欲產出，傾向高估生產單位的技術效率。另一方面，其係數估計值容易違反射線距離函數的先天性質，較不具參考性。而方向距離函數模型當中，有無加入限制條件與有無考慮環境變數的模型結果各不相同，其中同時加入限制條件與環境變數的模型結果最為合理。

本研究發展新的計量方法，運用隨機邊界法將單調性和曲度條件等性質納入迴歸模型，使用聯立迴歸模型進行估計，藉此讓係數估計值不易出現違反經濟理論的情況。 採用台灣2002年至2015年，51家商業銀行進行實證分析，發現本研究方法估計產出方向距離函數時，僅有5%以下的樣本點不符合單調和曲度等性質，用於估計產出面距離函數時，僅有2%以下的樣本點不符合。進一步探討台灣銀行業之非意欲產出--逾期放款--對估計技術效率的影響，顯示不考慮此非意欲產出造成整體銀行業、非金控本國銀行與外商銀行的技術效率被高估，而金控本國銀行的技術效率則被低估，此外，分析2007年金融風暴前後銀行業經營效率變化，顯示考慮非意欲產出銀行業經營效率顯著提升，然而，未考慮非意欲產出銀行業經營效率卻下降，兩者結果有著極大的差異。 / The aim of the paper is to develop a new approach, which is stochastic frontier analysis imposing monotonicity and curvature conditions, then using simultaneous regression model to estimate. By the approach, it can solve the problem of most of the coefficient estimates violating the economic theory. The study uses the data of 51 commercial banks in Taiwan from 2002 to 2015 to conduct the empirical analysis. It indicates that by output directional distance function, less than 5% sample points violate the monotonicity and curvature conditions; by output distance function, less than 2% sample points don’t obey the restricted conditions. Further, the paper discusses the effect of commercial banks’ undesirable output- non-performing loan- on estimating technical efficiency. The results show that ignoring the undesirable output cause the technical efficiency of overall banks, non-finance holding banks and foreign banks are overvalued, and the technical efficiency of finance holding banks are undervalued. Furthermore, analyze the change of business efficiency after financial crisis in 2007. It points out that using the model consider the undesirable output, the banks’ efficiency rises. However, using the model no consider the undesirable output, the banks’ efficiency decreases. There is an extremely conflict between two approach.