台灣民航機場隨機邊界生產函數及技術效率之分析

本文主要在探討台灣地區民航機場之生產函數型式及影響技術無效率之因素，所採用的是一般化超越對數生產函數，並引入三種不同的技術無效率效果模式，包括時變技術無效率模式、技術無效率效果模式及非中立邊界模式。邊界生產函數之結構由單一產出、三項投入及時間趨勢變數組成，產出定義為機場之勞務收入，投入則分為土地面積、員工薪資及中間投入；對技術無效率的衡量，在技術無效率效果模式及非中立邊界模式中，由影響技術效率之廠商特定因子所組成。本文以民國82年至88年台灣地區民航機場53筆不平衡之經緯資料，以最大概似法進行參數校估，實證結果以隨機邊界超越對數生產函數結合技術無效率之非中立邊界模式最適於說明台灣地區民航機場之生產結構與技術效率，而機場之技術效率範圍由9.4%至99.9%之間，平均技術效率僅達65.1%，影響技術效率之因素有機場之航線數目、土地面積，類型及時間趨勢。

關鍵字

航空站；隨機邊界模式；生產函數；技術無效率

並列摘要

In this paper we attempt to analyze the production functional form and technical efficiency affecting factors of airports in Taiwan. We consider translog stochastic frontier production functions in which the technical inefficiency effects are defined by three different models. The models involved are time-varying inefficiency model, the inefficiency effects model and non-neutral frontier model. The frontier is expressed in terms of one output variable, total revenue, together with the year of observation and three inputs, land area, labor and materials and services. The inefficiency effects model and the non-neutral frontier model specification include a technical inefficiency error term which is influenced by a number of firm-specific factors. Estimates of the parameters of the models are obtained using maximum likelihood estimation, applied to 53 observations from an unbalanced panel of 10 airports observed over 7 year period from 1993 to 1999. From these estimations, we obtain indices of technical efficiency. Moreover, the flexible functional form chosen, namely the translog stochastic frontier production. The mean technical efficiency of airports is estimated to be 65.1%, with the mean technical efficiencies of individual airports ranging from 9.4% to 99.9%. The differences to technical efficiencies among airports appear to be significantly influenced by routes of flight, land area, type of airport and year of observation.