A new DEA model has been introduced recently combining the primal and the dual models in order to impose strong complementary slackness conditions. It was claimed that a reference set that contains the maximum number of efficient units can then be determined. The model is very interesting as a...

Measuring productive efficiency is an important research strand within fields of economics, management science and operations research. One definition of efficiency is the proportional scaling needed for observations of an inefficient unit to be projected onto an efficient production function...

The performance of local tax offices of Norway is studied over a three-year period using Data Envelopment Efficiency analysis and calculating Malmquist productivity indices. One input, labour, is used, and six output categories of the main service activities carried out by tax offices are...

Many countries have followed a policy of being self-sufficient in electricity. However, in the last two decades exchange of electricity across borders has become more widespread, and the European Union's policy is to encourage a gradual expansion of cross-border trading and integration of...

The materials balance principle points to the crucial role of material inputs in generating residuals in production processes. Pollution modelling must be of a multi-output nature. The most flexible transformation function in outputs and inputs used in textbooks is too general to make sense in...

A dynamic analysis of structural change is reviewed based on a vintage model of substitutability between inputs including capital before investment, but no substitution possibilities after investment, and ex post production possibilities characterised by fixed input coefficients. Key elements in...

Attempts can be found in the DEA literature to identify returns to scale at efficient interior points of the production possibility set on the basis of returns to scale at points of the corresponding reference sets. However, an opposite approach is put forward in this paper, advocating that...