欧洲央行-时变集聚经济与总工资增长（英）

Working Paper Series Time-varying agglomeration economies and aggregate wage growth Clémence Berson, Pierre-Philippe Combes, Laurent Gobillon, Aurélie Sotura Disclaimer: This paper should not be reported as representing the views of the European Central Bank (ECB). The views expressed are those of the authors and do not necessarily reflect those of the ECB. No 2997 AbstractWe examine how agglomeration economies have influenced labour earnings in France overforty years. First, we define cities dynamically to account for their changing footprints. Ourfindings show that aggregate wage growth is mainly driven by growth in larger cities, ratherthan smaller ones or by population shifts across cities. We estimate individual wages incor-porating time-varying city and individual fixed effects, and analyse how city characteristics(employment density, area, and market access) and their returns impact wage evolution.Changes in the values of these characteristics have minimal effect, but changes in their re-turns significantly influence wages, with notable variation across cities. Overall, aggregatewage growth in France reflects larger returns to larger city size. Our model, that incorporatethe impact of agglomeration economies on city size and population, suggests that changesin returns do not drive population or area changes sufficiently to impact aggregate labourearnings, supporting our empirical findings.JEL Codes: R23, J31, J61Keywords:Agglomeration economies, endogenous city size, growth, wagesECB Working Paper Series No 29971Executive summaryOver the last fifty years, cities around the world have grown at different rates, with some countriesseeing the emergence of urban giants, concentrating population and employment. These largecities drive economic growth through productivity gains, innovation, and economies of scale. Ascities expand and adapt to structural changes—like the rise of service industries and improvedtransportation—returns to agglomeration economies have evolved, impacting labour earningsand aggregate productivity. This study examines the dual role of changes in city characteristicsand their returns in explaining aggregate labour earnings in France from 1976 to 2015.Our contribution is threefold. First, we delineate cities every year, enabling us to capturechanges in land area and not solely in population or employment. This approach allows for amore dynamic view of how cities grow, absorb surrounding areas, and sometimes merge. Second,we estimate the magnitude of agglomeration economies for three city variables: employmentdensity, land area, and market access. This helps us identify whether shifts in aggregate labourearnings are driven by changes in these city characteristics or by changes in their returns overtime. Finally, we model a system of cities with endogenous employment and land area to analysethe equilibrium effects of agglomeration economies on labour earnings. This model captures boththe direct impact of changes in agglomeration returns on