We use a flexible parametric hyperbolic distance function to estimate environmental efficiency when some outputs are undesirable. Cuesta and Zofio (J. Prod. Analysis (2005), 31-48) introduced this distance function specification in conventional input-output space to estimate technical efficiency...

Distance functions are gaining relevance as alternative representations of production technologies, with growing numbers of empirical applications being made in the productivity and efficiency field. Distance functions were initially defined on the input or output production possibility sets by...