Date Added: Jan 2010
The authors consider nonparametric identification in models of differentiated products markets, using only market level observables. On the demand side they consider a nonparametric random utility model nesting random coefficients discrete choice models widely used in applied work. They allow for product/market-specific unobservable, endogenous product characteristics, and high-dimensional taste shocks with arbitrary correlation and heteroskedasticity. On the supply side they specify marginal costs nonparametrically, allow for unobserved firm heterogeneity, and nest a variety of equilibrium oligopoly models. They pursue two approaches to identification.