Extremum estimation is typically an ad hoc semi-parametric estimation procedure which is only justified on the basis of the asymptotic properties of the estimators. For a fixed finite data set, consider a large number of investigations using different extremum estimators to estimate the same...

This essay is written with two goals. the first is to outline the main ideas underlying the growing study of complex economic environment. The second is to suggest areas of public policy where those ideas might be important.

In this paper we obtain bounds under weaker nonparametric assumptions and explore how the bounds with assumptions imposed.