Quantifying the Sources of Firm Heterogeneity *
构建并估计了一个多产品异质性企业模型，将企业规模分布分解为成本、吸引力、加成率和产品范围的贡献，发现企业吸引力和产品范围解释了至少五分之四的销售额差异，并指出标准生产率度量可能严重低估大企业的相对生产率。
Abstract We develop and structurally estimate a model of heterogeneous multiproduct firms that can be used to decompose the firm-size distribution into the contributions of costs, “appeal” (quality or taste), markups, and product scope. Using Nielsen barcode data on prices and sales, we find that variation in firm appeal and product scope explains at least four fifths of the variation in firm sales. We show that the imperfect substitutability of products within firms, and the fact that larger firms supply more products than smaller firms, implies that standard productivity measures are highly dependent on implicit demand system assumptions and probably dramatically understate the relative productivity of the largest firms. Although most firms are well approximated by the monopolistic competition benchmark of constant markups, we find that the largest firms that account for most of aggregate sales depart substantially from this benchmark, and exhibit both variable markups and substantial cannibalization effects.