The CCR model by Charnes et al. (Eur J Oper Res 2:429–444, 1978)
together with the BCC model by Banker et al. (Manag Sci 30:1078–1091, 1984)
are the most popular approaches of measuring efficiency among a group of decision
making units, DMUs, in data envelopment analysis, DEA. The right choice of a
DEA model—CCR or BCC—often, if not always, is a difficult decision. To evaluate
a DMU’s efficiency for both models might be helpful, but it does not always capture
the essential issues at stake. In this paper we propose a comparative analysis of both
concepts: How does activity scaling under constant BCC-efficiency influence CCRefficiency.
And inversely, how does BCC-efficiency behave when activity scaling
under constant CCR-efficiency is applied. Such findings of mutual effects improve a
DMU’s ability to reassess upsizing and downsizing of activities. Moreover, it allows
for exact calculations of the resulting economic effects, and these effects give new
insights beyond classical DEA. Finally, scale efficiency turns out to be the ideal
concept to control these activity changes, rather than just CCR- or BCC-efficiency.
We use a little numerical example to emphasize advantages of the new concept and
sketch the new findings for a theater scenery.