Efficiency is the main issue in any data envelopment analysis. Realizing output by a minimum of input or reaching a maximum of output by a given input is the credo, scale effects often are only a sort of accessory. In modern economics scale effects play a prominent role, however. What is the...

In data envelopment analysis (DEA), returns to scale (RTS) are a widely accepted instrument for a decision-making unit (DMU) to reveal its activity scaling potentials. In the case of increasing returns to scale (IRS), a DMU learns that upsizing activities improves its productivity. For...

DEA models help a DMU to detect its (in-)efficiency and to improve activities, if necessary. Efficiency is only one economic aim for a decision-maker; however, up- or downsizing might be a second one. Improving efficiency is the main topic in DEA; the long-term strategy towards the right production...