Propagation and Amplification of Local Productivity Spillovers

This paper shows that local productivity spillovers propagate throughout the economy through the plant-level networks of multi-region firms. Using confidential Census plant-level data, we show that large manufacturing plant openings not only raise the productivity of local plants but also of distant plants hundreds of miles away, which belong to multi-region firms that are exposed to the local productivity spillover through one of their plants. To quantify the significance of plant-level networks for the propagation and amplification of local productivity shocks, we develop and estimate a quantitative spatial model in which plants of multi-region firms are linked through shared knowledge. Our model features heterogeneous regions, which interact through goods trade and labor markets, as well as within-location, across-plant heterogeneity in productivity, wages, and employment. Counterfactual exercises show that while knowledge sharing through plant-level networks amplifies the aggregate effects of local productivity shocks, it widens economic disparities between individual workers and regions in the economy.