Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
This article employs the data envelopment analysis (DEA) approach to compute the environmental performance of all but two Organisation for Economic Co-operation and Development (OECD) countries. It is found that although the environmental performance of countries differs over time, Poland and Hungary are the two best performers for all periods while Italy, Japan, Austria and Switzerland are ranked among the worst. The effect of international regulations and some observed characteristics of countries on environmental performance are also investigated. International regulations are reported to have a positive effect on environmental performance.