The ratio definition of efficiency has the form of a productivity measure. But the weights are endogenous variables and they do not function as weights in a productivity index proper. It is shown that extended Farrell measures of efficiency can all be given an interpretation as productivity...

Research on productive efficiency at the firm level has developed as an important and active strand of research the last decades, both within operations research, management science and economics. However, the interests pursued within the fields have had some differences regarding sound...

The modelling of the interaction between production activities and the natural environment requires formulating a multioutput production function for intended and unintended outputs. The key feature when modelling joint production of intended outputs and unintended residuals is that the latter...