Multidimensional screening with complementary activities: regulating a monopolist with unknown cost and unknown preference for empire-building

We study optimal regulation of a monopolist when intrinsic efficiency (intrinsic cost) and empire-building tendency (marginal utility of output) are private information but actual cost (difference between intrinsic cost and effort level) is observable. This is a problem of multidimensional screening with complementary activities. Results are mainly driven by two elements: the correlations between types; and the relative magnitude of the uncertainty along the two dimensions of private information. If the marginal utility of output varies much more (resp. less) across managers than the intrinsic marginal cost, then we have empire-building (resp. efficiency) dominance. In that case, an inefficient empire-builder produces more (resp. less) and at lower (resp. higher) marginal cost than an efficient money-seeker. It is only when variabilities are similar that we obtain the natural ranking of activities (empire-builders produce more while efficient managers produce at a lower cost).