Steven T. Berry

Developed essential tools that enable the analysis of demand in differentiated product industries, and in analyzing features of the environment that determine the number of firms active in any given market. Work with  coauthors is frequently incorporated into merger and other policy decisions by public agencies and is spreading also to the private sector. His work on entry-the long-run mechanism by which markets adjust to changes in policy and environmental conditions-provided a framework for analyzing its determinants that was extensively used. Empirical work on the automobile, radio, and airline industries both demonstrated how the techniques he developed function and provided valuable information on the determinants of profits and consumer surplus in those industries. Contributed greatly as an editor of Econometrica.