In Grosskopf (1995) and Banker (1995) different approaches and problem
s of statistical inference in DEA frontier models are presented. This
paper focuses on the basic characteristics of DEA models from a statis
tical point of view. It arose from comments and discussions on both pa
pers above. The framework of DEA models is deterministic (all the obse
rved points lie on the same side of the frontier), nevertheless a stoc
hastic model can be constructed once a data generating process is defi
ned. So statistical analysis may be performed and sampling properties
of DEA estimators can be established. However, practical statistical i
nference (such as test of hypothesis, confidence intervals) still need
s artifacts like the bootstrap to be performed. A consistent bootstrap
relies also on a clear definition of the data generating process and
on a consistent estimator of it: The approach of Simar and Wilson (199
5) is described. Finally, some trails are proposed for introducing sto
chastic noise in DEA models, in the spirit of the Kneip-Simar (1995) a
pproach.