Abstract
Polyhedral Cone-Ratio Data Envelopment Analysis Models generalizing the CCR Ratio Model are developed for situations with a finite number of DMUs and employing polyhedral cones of virtual multipliers. They provide improved definitions of efficiency over CCR models whose input-output data and/or numbers of DMUs are inadequate to capture aspects or restrictions which should be involved. The focus here is on the sum form for cones which easily provides for capturing exogenous expert opinion as well as mathematical reduction to the old form with its very powerful software. Transformation from the usual intersection form to it and vice versa is explicitly given. Thereby the advantages of either or both are available. The theory is illustrated with two-dimensional examples and by real banking examples for motivation.