考慮非意欲產出下之公車營運效率分析

Abstract

本研究提出考慮非意欲產出之公車營運績效分析方法，並探討考慮非意欲產出與否對 於績效分析結果之影響。不包含非意欲產出的績效分析結果往往高於納入非意欲產出的績 效分析結果，顯示出忽略非意欲產出可能造成高估整體績效。

以往衡量運輸服務的績效是利用投入產出比，具有較多的產出與較少的單位被視為有 效率的單位。然而，在執行生產活動時，除了獲得意欲產出外，非意欲產出也伴隨產生， 例如污染排放，造成了外部成本。在環保議題受到重視的現今，運輸服務所帶來的外部成 本必須內部化，以促使營運單位為了追求效率，必須要盡可能減少非意欲產出。

資料包絡分析常被用於衡量多投入與多產出的績效，但無法處理非意欲產出。本研究 採取差額式評量模式之改良模式—不可分割好/壞產出模式去衡量台北十四家民營公車業 者之績效，分析業者在納入非意欲產出與否的不同狀況下，其效率的變化情形，並在管理 意涵上有所詮釋。

The purpose of this research is to investigate how undesirable outputs influence performance. The efficiency scores are overestimated under considering without undesirable output, which shows that ignoring undesirable output may cause bias when estimating efficiency. As the environmental issues are taken seriously, undesirable outputs should be taken into the efficiency model, which urges the firms concern not only increasing good outputs but also decreasing bad outputs.

Data envelopment analysis (DEA) is an approach applied to measure multiple input-output efficiency of decision making units (DMUs). However, classical DEA model cannot deal with undesirable outputs, this research introduces SBM model (non-separable inputs/outputs model) to estimate the efficiency.

The data of Taipei bus transit firms over 2007 to 2010 is used for the case study, wherein the CO emission is selected as undesirable output. Our findings indicate that many efficiency DMUs become inefficiency if involving undesirable output into the DEA model. Furthermore, this research give some suggestions to improve efficiency.