The integrated efficiency of economic development and CO2 emissions among Asia Pacific Economic Cooperation members

In recent years, the evaluation of energy, economic and environmental efficiency, employing the data envelopment analysis models, has been a hot topic in academe. When choosing models, people always expect to improve desirable outputs, while reducing undesirable outputs at the same time (e.g. when using a directional distance function model). However, directional distance function models may lead to biased estimations due to different directions given to different units. To overcome this shortcoming, in this paper, we propose another non-radial efficiency evaluation model based on previous literature, which can also improve desirable outputs and reduce undesirable outputs. Then we employ this model to analyse the economic efficiency and CO2 emissions efficiency of the Asia Pacific Economic Cooperation (APEC) members. Meanwhile, we also measure the efficiency change by using the Luenberger index, and analyse the reasons for efficiency changes from the perspectives of technical efficiency, and technical, changes. The results indicate that most countries have an extremely high economic efficiency, but relatively low CO2 emissions efficiency and integrated efficiency except for the United States, Japan, and Singapore. According to the Luenberger index, we find an increase in integrated efficiency and CO2 emissions efficiency for most members from 2001 to 2010; however, technical progress is the main contributor. Technical efficiency exhibits a downward trend for most members.