This package, written for Mathcad 15, is a comprehensive solver for a wide range of Data Envelopment Models (DEA). I've used it on quite large models and also for calculating improvement stragegies for sectors of New Zealand's Tourism Industry using inputs derived from Statistics NZ. It covers the usual Constant and Variable returns to Scale problems, accepts either input or output orientation and has the added feature of also calculating Capacity Utilisation - essentially a DEA model, but some of the inputs are fixed whilst others are variable (e.g. Capital Stock might be regarded as a fixed input).
There are three solver systems: 1) the solution of either Input or Output DEA models, 2) the Calculation of Exemplars for non-exemplary DMUs and the calculation of slacks - and finally 3) the Capacity Utilisation solutions for a mix of variable and fixed inputs.
The use of the Solver Block is a bit novel as it is completely parameterised and works like a dream!
Models can be copied in from Excel and the overall final tableau sent back to Excel in the same fashion.
A few caveats: the application of DEA can be contentious as the actual behaviours of the DMUs are 'assumed' to vary with scale in some fashion or other (but in reality they might not). Also, this formulation does not pre-solve for the 'archimedian' (a non-zero but infinitesmal constraint that is part of the classical solution set). This model simply assumes the archimedian to be zero and that has worked in all but the most extreme of situations (such as where the data is exceeedingly large - as might be the case if inputs represented, say, Yen or the populations of large countries. Also, in DEA, inputs should be at least 3*outputs for credibility (test sets excepted). Some test sets are included to get the user started.
Regards
John P Moriarty
