Heterogeneous firms, agglomeration and economic geography: spatial selection and sorting
将Melitz异质性企业模型融入新经济地理模型，发现生产率最高的企业最倾向于迁往大区域，导致标准实证测量高估集聚经济，且区域政策会引发高生产率企业向核心区、低生产率企业向边缘区的分类效应。
A Melitz-style model of monopolistic competition with heterogeneous firms is integrated into a simple new economic geography model to show that the standard assumption of identical firms is neither necessary nor innocuous. We show that relocating to the big region is most attractive for the most productive firms; this implies interesting results for empirical work and policy analysis. A 'selection effect' means standard empirical measures overestimate agglomeration economies. A 'sorting effect' means that a regional policy induces the highest productivity firms to move to the core and the lowest productivity firms to the periphery. We also show that heterogeneity dampens the home market effect. © 2006 Oxford University Press.