Theory and Empirical Work on Imperfectly Competitive Markets

This paper reviews recent methodological developments in the empirical analysis of imperfectly competitive markets highlighting outstanding problems. Some of these problems are econometric; e.g. the need for a deeper understanding of the small sample properties of our estimators. Most of the other problems relate to issues which have been a central part of ongoing research programs in economic theory for some time. We consider ways in which applied work can cope with these problems and, in so doing, also inform theory. The use of estimators based on moment inequalities opens up several possibilities in this regard and a detailed discussion of the assumptions used to rationalize these estimators is provided. An example, the analysis of contracts in buyer-seller networks, is used to highlight these points.