西藏自治區之農家生產效率分析

Abstract

西藏自治區位於青藏高原西南部，氣候與地形複雜而多樣，加上區域之間資源分布極度不均，農業發展問題一直受到各界與國際組織的關注。本文利用2002年西藏自治區政府的531戶農家抽樣調查資料以及資料包絡法（Data Envelopment Analysis, DEA）來分析西藏自治區內的農家生產效率，並以Tobit迴歸模型分析其影響因素。研究範圍包括拉薩市及阿里、林芝、日喀則、山南、那曲、以及昌都7地區，考量到各區的生產產品種類與技術均有很大的差異，因此本文採用共同生產邊界（Meta-frontier）DEA的方式來比較各地區的差異。分析結果顯示，西藏農家的平均技術效率、分配效率、以及規模效率值分別為0.478、0.844、0.838，超過6成以上的西藏農家之技術效率值小於0.50，但分配及規模效率值小於0.50的農家則分別僅占 5.1%及4.1%。透過共同生產邊界的分析結果則顯示西藏6個地區當中，那曲地區之生產技術與西藏整體的生產技術差異最小，而阿里地區之差異最大。就影響農家生產效率因素而言，阿里、那曲及林芝等地區平均具有較高的技術效率，而生產同時用以自用及銷售的農家，其技術及分配效率會較完全出售或完全自用之農家來得高，另外，本研究也發現農場規模雖會提高農家的分配效率，卻也同時會降低其技術效率，而非農業所得雖會對技術效率帶來正面影響，但卻會減少分配效率。

This study uses a 2002 data of 531 farm households in Tibet for analyzing production efficiencies-technical efficiency, allocative efficiency, and scale efficiency. The output-orientated traditional and meta-frontier DEA are both adopted for regional comparison. The self-consumption value is selected as one of the outputs in the household-level analysis. A Tobit regression model is also applied to determine the factors that have impact on household efficiencies. The DEA results exhibit that over 60 percent of farm households have a technical efficiency scores below 0.50, while the percentages are much smaller, only 5.1% and 4.1% for allocative and scale efficiencies, respectively. The meta-technology ratios of regional technical efficiency show that the lowest and highest ratios can be found in Ngari and Nakchu, respectively. Furthermore, the evidence of Tobit regression reports that Nyingtri, Nakchu, and Ngari have higher technical efficiencies. The technical and allocative efficiencies of semi-subsistence farm households are higher as compared to commercial and pure-subsistence households. Farm size enlargement increases allocative efficiency, but lower the technical efficiency and thus result in an overall efficiency loss. On the other hand, the off-farm income is helpful for farm households to increase their technical efficiency but at a cost of losing allocative efficiency.