本文的主要研究目的是採用方向性距離函數，除考量經濟發展的正向意欲產出，並納入負向的CO2非意欲產出，估算所有樣本國的共同邊界效率、各國所分屬的子群組邊界效率，以及達到整體理想最佳生產技術的追趕概況。結果顯示，共同邊界效率值與共同技術比率的變動趨勢大致與各國發展程度一致。即發展程度高的國家，平均而言擁有較佳的生產技術水準，於是加強相關政策管理以提升生產效率水準，將是首要之務。而發展程度低的國家，一如發展程度高的國家，除了要朝向潛在最佳生產技術效率水準邁進之外，尚須戮力往最佳生產技術水準前進。

The use of the directional distance function along with the meta-frontier analysis is to account for the desired output of economic development and the undesired output of CO2 emissions while the comparisons of the technical efficiencies for the overall sample countries and sub-group of the countries are made. The comparisons of technical efficiency performances are computed for the difference between a specific country and a sub-group of the countries and the meta-frontier technical efficiency that the specific country can capture up. The significant factors of institutional environment are then identified. The results show that except for the group of the low-income countries, part of the countries from all other three group countries, low middle-income, upper middle-income, and high income countries, have potential to reach the most efficient of the metafrontier. On average, the higher level of the economic development is the higher level of the production technology is. The management of the related policy to improve technical efficiency becomes crucial for this type of country. On the contrary, countries at low level of economic development not only have to improve technical efficiency but also have to increase the level of production technology.