'Multilateral productivity comparisons when some outputs are undesirable: A nonparametric approach'

Multilateral productivity comparisons of firms producing multiple outputs, some of which are undesirable, are obtained by making two modifications to the standard Farrell approach to efficiency measurement. The restriction that production technology satisfy strong disposability of outputs is relaxed to allow for the fact that undesirable outputs may be freely disposable, and the efficiency measures are modified to allow for an asymmetric treatment of desirable and undesirable outputs. Performance measures that satisfy these requirements are calculated as solutions to programming problems. The methodology is applied to a sample of mills producing paper and pollutants