A conditional directional distance function approach for measuring regional environmental efficiency: Evidence from the UK regions

This paper, by using conditional directional distance functions as introduced by Simar and Vanhems [J. Econometrics 166 (2012) 342-354] modifies the model by Färe and Grosskopf [Eur. J. Operat. Res. 157 (2004) 242-245], examines the link between regional environmental efficiency and economic growth. The proposed model using conditional directional distance functions incorporates the effect of regional economic growth on regions’ environmental efficiency levels. The results from the UK regional data reveal that economic growth has a negative effect on regions’ environmental performance up to a certain GDP per capita level, where after that point the effect becomes positive. This indicates the existence of a Kuznets type relationship between the UK regions’ environmental performance and economic growth.