Sánchez De La Sierra R. On the origins of the state: Stationary bandits and taxation in eastern congo[J]. Journal of Political Economy, 2020, 128(1): 1-43.
Abstract: A positive demand shock for coltan, a mineral whose bulky output cannot be concealed, leads armed actors to create illicit customs and provide protection at coltan mines, where they settle as “stationary bandits.” A similar shock for gold, easy to conceal, leads to stationary bandits in the villages where income from gold is spent, where they introduce illicit mining visas, taxes, and administrations. Having a stationary bandit from a militia or the Congolese army increases welfare. These findings suggest that armed actors may create “essential functions of a state” to better expropriate, which, depending on their goals, can increase welfare.
Fajgelbaum, P. D., Morales, E., Serrato, J. C. S., & Zidar, O. (2019). State Taxes and Spatial Misallocation. Review of Economic Studies, (86), 333–376.
Abstract: We study state taxes as a potential source of spatial misallocation in the U.S.. We build a spatial general equilibrium framework that incorporates salient features of the U.S. state tax system, and use changes in state tax rates between 1980 and 2010 to estimate the model parameters that determine how worker and firm location respond to changes in state taxes. We find that heterogeneity in state tax rates leads to aggregate welfare losses. In terms of consumption equivalent units, harmonizing state taxes increases worker welfare by 0.6% if government spending is held constant, and by 1.2% if government spending responds endogenously. Harmonization of state taxes within Census regions achieves most of these gains. We also use our model to study the general equilibrium effects of recently implemented and proposed tax reforms.
Hsieh, C.-T., Hurst, E., Jones, C. I., & Klenow, P. J. (2019). The Allocation of Talent and U.S. Economic Growth. Econometrica, 87(5), 1439–1474.
Abstract: In 1960, 94 percent of doctors and lawyers were white men. By 2010, the fraction was just 62 percent. Similar changes in other highly‐skilled occupations have occurred throughout the U.S. economy during the last 50 years. Given that the innate talent for these professions is unlikely to have changed differently across groups, the change in the occupational distribution since 1960 suggests that a substantial pool of innately talented women and black men in 1960 were not pursuing their comparative advantage. We examine the effect on aggregate productivity of the convergence in the occupational distribution between 1960 and 2010 through the prism of a Roy model. Across our various specifications, between 20% and 40% of growth in aggregate market output per person can be explained by the improved allocation of talent.
Young, A. (2014). Structural Transformation, the Mismeasurement of Productivity Growth, and the Cost Disease of Services. American Economic Review, 1–51.
Abstract: If workers self-select into industries based upon their relative productivity in different tasks, and comparative advantage is aligned with absolute advantage, then the average efficacy of a sector's workforce will be negatively correlated with its employment share. This might explain the difference in the reported productivity growth of contracting goods and expanding services. Instrumenting with defense expenditures, I find the elasticity of worker efficacy with respect to employment shares is substantially negative, albeit imprecisely estimated. The estimates suggest that the view that goods and services have similar productivity growth rates is a plausible alternative characterization of growth in developed economies.
Jones C I, Kim J. A Schumpeterian model of top income inequality[J]. Journal of Political Economy, 2018, 126(5): 1785-1826.
Abstract: Top income inequality rose sharply in the United States over the last 40 years but increased only slightly in France and Japan. Why? We explore a model in which heterogeneous entrepreneurs, broadly interpreted, exert effort to generate exponential growth in their incomes, which tends to raise inequality. Creative destruction by outside innovators restrains this expansion and induces top incomes to obey a Pareto distribution. Economic forces that affect these two mechanisms—including information technology, taxes, and policies related to innovation blocking—may explain the varied patterns of top income inequality that we see in the data.
Land Misallocation, Property Rights and Agricultural Efficiency in China (with A.V. Chari, Elaine Liu and Shing-Yi Wang), Forthcoming at Review of Economic Studies
Abstract：This paper examines the impact of a property rights reform in rural China that allowed farmers to lease out their land. We find the reform led to increases in land rental activity in rural households. Consistent with a model of transaction costs in land markets, our results indicate that the formalization of leasing rights resulted in a redistribution of land toward more productive farmers. Consequently, the aggregate productivity of land increased significantly. We also find that the reform increased the responsiveness of land allocation across crops to changes in crop prices.
Glaeser E L. Urbanization and its Discontents[J]. Eastern Economic Journal, 2020: 1-28.
Abstract: American cities have experienced a remarkable renaissance over the past 40 years, but in recent years, cities have experienced considerable discontent. Anger about high housing prices and gentrification has led to protests. The urban wage premium appears to have disappeared for less skilled workers. The cities of the developing world are growing particularly rapidly, but in those places, the downsides of density are acute. In this essay, I review the causes of urban discontent and present a unified explanation for this unhappiness. Urban resurgence represents private sector success, and the public sector typically only catches up to urban change with a considerable lag. Moreover, as urban machines have been replaced by governments that are more accountable to empowered residents, urban governments do more to protect insiders and less to enable growth. The power of insiders can be seen in the regulatory limits on new construction and new businesses, the slow pace of school reform and the unwillingness to embrace congestion pricing.
Atalay, Enghin, et al. "How wide is the firm border?." The Quarterly Journal of Economics 134.4 (2019): 1845-1882.
Abstract: We examine the within- and across-firm shipment decisions of tens of thousands of goods-producing and distributing establishments. This allows us to quantify the normally unobservable forces that determine firm boundaries; which transactions are mediated by ownership control, as opposed to contracts or markets. We find firm boundaries to be an economically significant barrier to trade: having an additional vertically integrated establishment in a given destination zip code has the same effect on shipment volumes as a 40 percent reduction in distance. We then calibrate a multisector trade model to quantify the economy-wide implications of transacting across vs. within firm boundaries.
Sterk, Vincent, Petr Sedláček, and Benjamin Pugsley. "The nature of firm growth." American Economic Review 111.2 (2021): 547-79.
Abstract: About one-half of all startups fail within five years, and those that survive grow at vastly different speeds. Using Census microdata, we estimate that most of these differences are determined by ex ante heterogeneity rather than persistent ex post shocks. Embedding such heterogeneity in a firm dynamics model shows that the presence of ex ante heterogeneity (i) is a key determinant of the firm size distribution and firm dynamics, (ii) can strongly affect the macroeconomic effects of firm-level frictions, and (iii) helps understand the recently documented decline in business dynamism by showing a disappearance of high-growth startups (“gazelles”) since the mid-1980s.
Morten, M. & Oliveira, J. (2018). The Effects of Roads on Trade and Migration: Evidence from a Planned Capital City. NBER Working Paper 22158
Abstract: A large body of literature studies how infrastructure facilitates the movement of traded goods. We ask whether infrastructure also facilitates the movement of labor. We use a general equilibrium trade model and rich spatial data to explore the impact of a large plausibly exogenous shock to highways in Brazil on both goods markets and labor markets. We find that the road improvement increased welfare by 13.3%, of which 95% was due to reduced trade costs and 5% to reduced migration costs. Nevertheless, costly migration is responsible for large spatial heterogeneity in the benefits of roads: the interquartile range of welfare improvement is 6%–23%, as opposed to uniform gains with perfect mobility.
Lane N. Manufacturing revolutions: Industrial policy and industrialization in south korea[J]. Monash University Paper, 2019.
Abstract：I study the impact of industrial policy on industrial development through a canonical intervention. Following a political crisis in 1972, South Korea dramatically altered its development strategy with a new sector-specific policy: the Heavy Chemical and Industry (HCI) drive. With newly digitized data, I use the sharp introduction and withdrawal of HCI trade policy and investment incentives to study its impacts. (1) I show HCI successfully promoted the evolution of directly treated industries. Next I provide evidence for two key justifications of industrial policy: network and dynamic externalities. (2) Using variation in exposure to policies through the input-output network, I show HCI indirectly benefited (non-treated) downstream industry. (3) Finally, I show both direct and indirect benefits of HCI persist even after the policy is withdrawn, following the 1979 assassination of President Park. Together, my findings suggest that the temporary drive helped shift the economy into higher value-added activity.
Azar J, Vives X. General Equilibrium Oligopoly and Ownership Structure[J].Econometrica 2021.
Abstract：We develop a tractable general equilibrium framework in which firms are large and have market power with respect to both products and labor, and in which a firm’s decisions are affected by its ownership structure. We characterize the Cournot–Walras equilibrium of an economy where each firm maximizes a share-weighted average of shareholder utilities—rendering the equilibrium inde- pendent of price normalization. In a one-sector economy, if returns to scale are non-increasing then an increase in “effective” market concentration (which accounts for common ownership) leads to de- clines in employment, real wages, and the labor share. Yet when there are multiple sectors, due to an intersectoral pecuniary externality, an increase in common ownership could stimulate the econ- omy when the elasticity of labor supply is high relative to the elasticity of substitution in product markets. We characterize for which ownership structures the monopolistically competitive limit or an oligopolistic one are attained as the number of sectors in the economy increases. When firms have heterogeneous constant returns to scale technologies we find that an increase in common ownership leads to markets that are more concentrated.
Carvalho V M, Nirei M, Saito Y, et al. Supply chain disruptions: Evidence from the great east japan earthquake[J]. The Quarterly Journal of Economics. 2021
Abstract：Exploiting the exogenous and regional nature of the Great East Japan Earthquake of 2011, this paper provides a quantification of the role of input-output linkages as a mechanism for the propa- gation and amplification of shocks. We document that the disruption caused by the disaster prop- agated upstream and downstream supply chains, affecting the direct and indirect suppliers and customers of disaster-stricken firms. Using a general equilibrium model of production networks, we then obtain an estimate for the overall macroeconomic impact of the disaster by taking these propagation effects into account. We find that the earthquake and its aftermaths resulted in a 0.47 percentage point decline in Japan’s real GDP growth in the year following the disaster.
Dingel J I, Tintelnot F. Spatial Economics for Granular Settings[R]. National Bureau of Economic Research, 2021.
Abstract: We examine the application of quantitative spatial models to the growing body of fine spatial data used to study economic outcomes for regions, cities, and neighborhoods. In “granular” settings where people choose from a large set of potential residence-workplace pairs, idiosyncratic choices affect equilibrium outcomes. Using both Monte Carlo simulations and event studies of neighborhood employment booms, we demonstrate that calibration procedures that equate observed shares and modeled probabilities perform very poorly in such settings. We introduce a general-equilibrium model of a granular spatial economy. Applying this model to Amazon’s proposed HQ2 in New York City reveals that the project’s predicted consequences for most neighborhoods are small relative to the idiosyncratic component of individual decisions in this setting. We propose a convenient approximation for researchers to quantify the “granular uncertainty” accompanying their counterfactual predictions.
Heblich S, Redding S J, Sturm D M. The making of the modern metropolis: evidence from London[J]. The Quarterly Journal of Economics, 2020, 135(4): 2059-2133.
Abstract: Using newly constructed spatially disaggregated data for London from 1801 to 1921, we show that the invention of the steam railway led to the first large-scale separation of workplace and residence. We show that a class of quantitative urban models is remarkably successful in explaining this reorganization of economic activity. We structurally estimate one of the models in this class and find substantial agglomeration forces in both production and residence. In counterfactuals, we find that removing the whole railway network reduces the population and the value of land and buildings in London by up to 51.5% and 53.3% respectively, and decreases net commuting into the historical center of London by more than 300,000 workers.
Fajgelbaum P D, Schaal E. Optimal transport networks in spatial equilibrium[J]. Econometrica, 2020, 88(4): 1411-1452.
Abstract: We study optimal transport networks in spatial equilibrium. We develop a framework consisting of a neoclassical trade model with labor mobility in which locations are arranged on a graph. Goods must be shipped through linked locations, and transport costs depend on congestion and on the infrastructure in each link, giving rise to an optimal transport problem in general equilibrium. The optimal transport network is the solution to a social planner's problem of building infrastructure in each link. We provide conditions such that this problem is globally convex, guaranteeing its numerical tractability. We also study cases with increasing returns to transport technologies in which global convexity fails. We apply the framework to assess optimal investments and inefficiencies in the road networks of European countries.
Balboni, Clare, et al. "Transportation, Gentrification, and Urban Mobility: The Inequality Effects of Place-Based Policies." (2020).
Abstract：Roads, rail, and other public transport in a city are “place-based,” in that they are built in specific neighborhoods. Do such investments benefit the poor? If people are mobile within a city, then any such place-based investment can lead to neighborhood changes, such as rent increases, which change who can afford to live near these invest- ments and hence who benefits from them. We provide a tractable urban commuting model to study the distributional effects of urban infrastructure improvements. We derive intuitive “exact hat” expressions for the welfare change of initial residents after investment. We then apply the method to study the Dar es Salaam BRT system, using original panel data tracked on two dimensions (following households if they move and surveying all new residents of buildings). Preliminary results suggest that the BRT was a pro-poor investment: we estimate a welfare gain of 3.0% for incumbent low-income residents living near the BRT, compared with a 2.5% gain to incumbent high-income residents; across the city, poor gained on average 2.4% and rich gained 2.3%.
Bartik IV主题(Shift-share design)
Goldsmith-Pinkham P , Sorkin I , Swift H . Bartik Instruments: What, When, Why, and How[J]. NBER Working Papers, 2018.
Abstract: The Bartik instrument is formed by interacting local industry shares and national industry growth rates. We show that the Bartik instrument is numerically equivalent to using local industry shares as instruments. Hence, the identifying assumption is best stated in terms of these shares, with the national industry growth rates only affecting instrument relevance. We then show how to decompose the Bartik instrument into the weighted sum of the just-identified instrumental variables estimators, where the weights sum to one, can be negative and are easy to compute. These weights measure how sensitive the parameter estimate is to each instrument. We illustrate our results through three applications: estimating the inverse elasticity of labor supply, estimating local labor market effects of Chinese imports, and using simulated instruments to study the effects of Medicaid expansions.
Borusyak K , Hull P , Jaravel X . Quasi-experimental Shift-share Research Designs[J]. NBER Working Papers, 2018.
Abstract: Many empirical studies leverage shift-share (or “Bartik”) instruments that average a set of observed shocks with shock exposure weights. We de- rive a necessary and sufficient shock-level orthogonality condition for these instruments to identify causal effects. We then show that orthogonality holds when observed shocks are as-good-as-randomly assigned and growing in number, with the average shock exposure sufficiently dispersed. Quasi- experimental shift-share designs may be implemented with new shock-level procedures, which help visualize the identifying variation, correct standard errors, choose appropriate specifications, test identifying assumptions, and optimally combine multiple sets of quasi-random shocks. We illustrate these ideas by revisiting Autor et al. (2013)’s analysis of the labor market effects of Chinese import competition.
Ado R , Michal Kolesár, Morales E . Shift-Share Designs: Theory and Inference[J]. The Quarterly Journal of Economics, 2019, 134.
Abstract: We study inference in shift-share regression designs, such as when a regional outcome is re- gressed on a weighted average of sectoral shocks, using regional sector shares as weights. We conduct a placebo exercise in which we estimate the effect of a shift-share regressor constructed with randomly generated sectoral shocks on actual labor market outcomes across U.S. Commuting Zones. Tests based on commonly used standard errors with 5% nominal significance level reject the null of no effect in up to 55% of the placebo samples. We use a stylized economic model to show that this overrejection problem arises because regression residuals are correlated across regions with similar sectoral shares, independently of their geographic location. We derive novel inference methods that are valid under arbitrary cross-regional correlation in the regression residuals. We show using popular applications of shift-share designs that our methods may lead to substantially wider confidence intervals in practice.
Horn S , Reinhart C M , Trebesch C . China's Overseas Lending[J]. CEPR Discussion Papers, 2020.
Compared with China’s pre-eminent status in world trade, its role in global finance is poorly understood. This paper studies the size, characteristics, and determinants of China’s capital exports building a new database of 5000 loans and grants to 152 countries, 1949-2017. We find that 50% of China’s lending to developing countries is not reported to the IMF or World Bank. These “hidden debts” distort policy surveillance, risk pricing, and debt sustainability analyses. Since China’s overseas lending is almost entirely official (state-controlled), the standard “push” and “pull” drivers of private cross-border flows do not apply in the same way.
（推荐人：钟辉勇）
Abadie A, Athey S, Imbens G W, et al. When Should You Adjust Standard Errors for Clustering[J]. National Bureau of Economic Research, 2017.
In empirical work in economics it is common to report standard errors that account for clustering of units. Typically, the motivation given for the clustering adjustments is that unobserved components in outcomes for units within clusters are correlated. However, because correlation may occur across more than one dimension, this motivation makes it difficult to justify why researchers use clustering in some dimensions, such as geographic, but not others, such as age cohorts or gender. This motivation also makes it difficult to explain why one should not cluster with data from a randomized experiment. In this paper, we argue that clustering is in essence a design problem, either a sampling design or an experimental design issue. It is a sampling design issue if sampling follows a two stage process where in the first stage, a subset of clusters were sampled randomly from a population of clusters, and in the second stage, units were sampled randomly from the sampled clusters. In this case the clustering adjustment is justified by the fact that there are clusters in the population that we do not see in the sample. Clustering is an experimental design issue if the assignment is correlated within the clusters. We take the view that this second perspective best fits the typical setting in economics where clustering adjustments are used. This perspective allows us to shed new light on three questions: (i) when should one adjust the standard errors for clustering, (ii) when is the conventional adjustment for clustering appropriate, and (iii) when does the conventional adjustment of the standard errors matter.
（推荐人：唐珏）
研究主题：充分统计量Sufficient Statistics
推荐语by刘志阔：近年来，充分统计量（Sufficient Statistics）的应用范围不仅局限于公共经济学，被更多领域和学者逐渐接受，Chetty和Kleven两位教授在ARE写了两篇综述性文章，值得研读。
Kleven H. Sufficient Statistic Revisited [J]. NBER Working Papers, 2020.
This paper reviews and generalizes the sufficient statistics approach to policy evaluation. The idea of the approach is that the welfare effect of policy changes can be expressed in terms estimable reduced-form elasticities, allowing for policy evaluation without estimating the structural primitives of fully specified models. The approach relies on three assumptions: that policy changes are small, that government policy is the only source of market imperfection, and that a set of high-level restrictions on the environment and on preferences can be used to reduce the number of elasticities to be estimated. We generalize the approach in all three dimensions. It is possible to develop transparent sufficient statistics formulas under very general conditions, but the estimation requirements increase greatly. Starting from such general formulas elucidates that feasible empirical implementations are in fact structural approaches.
Chetty, Raj. "Sufficient statistics for welfare analysis: A bridge between structural and reduced-form methods." Annu. Rev. Econ. 1.1 (2009): 451-488.
The debate between structural and reduced-form approaches has generated substantial controversy in applied economics. This article reviews a recent literature in public economics that combines the advantages of reduced-form strategies—transparent and credible identification—with an important advantage of structural models—the ability to make predictions about counterfactual outcomes and welfare. This literature has developed formulas for the welfare consequences of various policies that are functions of reduced-form elasticities rather than structural primitives. I present a general framework that shows how many policy questions can be answered by estimating a small set of sufficient statistics using program-evaluation methods. I use this framework to synthesize the modern literature on taxation, social insurance, and behavioral welfare economics. Finally, I discuss problems in macroeconomics, labor, development, and industrial organization that could be tackled using the sufficient statistic approach.
研究主题：Trade War
推荐语by刘志阔：贸易战以来，出现一系列讨论贸易战的文章，值得放到一起来研读，尤其QJE和AER的两篇文章。
Fajgelbaum, P. D., Goldberg, P. K., Kennedy, P. J., & Khandelwal, A. K. (2020). The return to protectionism. The Quarterly Journal of Economics, 135(1), 1-55.
After decades of supporting free trade, in 2018 the U.S. raised import tariffs and major trade partners retaliated. We analyze the short-run impact of this return to protectionism on the U.S. economy. Import and retaliatory tariffs caused large declines in imports and exports. Prices of imports targeted by tariffs did not fall, implying complete pass-through of tariffs to duty-inclusive prices. The resulting losses to U.S. consumers and firms who buy imports was $51 billion, or 0.27% of GDP. We embed the estimated trade elasticities in a general-equilibrium model of the U.S. economy. After accounting for tariff revenue and gains to domestic producers, the aggregate real income loss was $7.2 billion, or 0.04% of GDP. Import tariffs favored sectors concentrated in politically competitive counties, and the model implies that tradeable-sector workers in heavily Republican counties were the most negatively affected due to the retaliatory tariffs.
Flaaen, Aaron, Ali Hortaçsu, and Felix Tintelnot. "The production relocation and price effects of US trade policy: the case of washing machines." American Economic Review 110.7 (2020): 2103-27.
We analyze several rounds of U.S. import restrictions against washing machines. Using retail price data, we estimate the price effect of these import restrictions by comparing the price changes of washers with those of other appliances. We find that in response to the 2018 tariffs on nearly all source countries, the price of washers rose by nearly 12 percent; the price of dryers—a complementary good not subject to tariffs—increased by an equivalent amount. Factoring in the effect of dryers and price increases by domestic brands, our estimates for the 2018 tariffs on washers imply a tariff elasticity of consumer prices of between 110 and 230 percent. The 2016 antidumping duties against China—which accounted for the overwhelming majority of U.S. imports—led to minor price movements due to subsequent production relocation to other export platform countries. Perhaps surprisingly, the 2012 antidumping duties against Korea led to relocation of production to China, actually resulting in lower washer prices in the United States. We find that our measure of the tariff elasticity of consumer prices may differ in sign and magnitude from conventional pass-through estimates which are based on a regression of country-specific import price changes on country-specific tariff changes. Production relocation effects, price changes by domestic brands,and price changes of complementary goods all contribute to the differences between these measures.
Cavallo, A., Gopinath, G., Neiman, B., & Tang, J. (2019). Tariff passthrough at the border and at the store: evidence from US trade policy (No. w26396). National Bureau of Economic Research.
We use micro data collected at the border and at retailers to characterize the effects brought by recent changes in US trade policy -- particularly the tariffs placed on imports from China -- on importers, consumers, and exporters. We start by documenting that the tariffs were almost fully passed through to total prices paid by importers, suggesting the tariffs' incidence has fallen largely on the US. Since we estimate the response of prices to exchange rates to be far more muted, the recent depreciation of the Chinese Renminbi is unlikely to alter this conclusion. Next, using product-level data from several large multi-national retailers, we demonstrate that the impact of the tariffs on retail prices is more mixed. Some affected product categories have seen sharp price increases, but the difference between affected and unaffected products is generally quite modest, suggesting that retail margins have fallen. These retailers' imports increased after the initial announcement of tariffs, so the intermediate passthrough of tariffs to their prices may not persist. Finally, in contrast to the case of foreign exporters facing US tariffs, we show that US exporters lowered their prices on goods subjected to foreign retaliatory tariffs compared to exports of non-targeted goods.
Tatyana Deryugina, Garth Heutel, Nolan H. Miller, David Molitor, Julian Reif.”The Mortality and Medical Costs of Air Pollution: Evidence from Changes in Wind Direction.” American Economic Review,109.12(2019): 4178-4219.
Abstract：We estimate the causal effects of acute fine particulate matter exposure on mortality, health care use, and medical costs among the US elderly using Medicare data. We instrument for air pollution using changes in local wind direction and develop a new approach that uses machine learning to estimate the life-years lost due to pollution exposure. Finally, we characterize treatment effect heterogeneity using both life expectancy and generic machine learning inference. Both approaches find that mortality effects are concentrated in about 25 percent of the elderly population.
推荐语by匿名：这个其实有较多同类文献，这篇能发AER，应该有其独特之处。其中提到机器学习，可以关注。
Sebastian Heise, Tommaso Porzio(2019)"Spatial Wage Gaps in Frictional Labor Markets", NBER working paper
Abstract: We develop a job ladder model with labor reallocation across firms and space to study why differences in wages and labor productivity persist across regions within the same country. We apply the model to Germany, where real wages are still 26% lower in the East than in the West. Estimating the model on matched employer-employee data, we find that 60% of the gap is due to the fact that workers are paid a higher wage per efficiency unit in West Germany. We quantify a rich set of frictions preventing worker reallocation across space and across firms, and find that three spatial barriers impede East Germans’ ability to migrate West: migration costs, workers’ preferences to live in their home region, and more frequent job opportunities received from home. The estimated model highlights that the spatial barriers needed to generate the large wage gap between East and West are small relative to the frictions preventing the reallocation of labor across firms. As a result, policies that directly promote regional integration lead to smaller aggregate benefits than equally costly subsidies to worker hiring within region. Our findings show the importance of studying spatial wage gaps and frictional wage dispersion within a unified framework.
Lorenzo Caliendo, Luca David Opromolla, Fernando Parro, Alessandro Sforza(2017). "Goods and Factor Market Integration: A Quantitative Assessment of the EU Enlargement.” NBER working paper
Abstract: The economic effects from labor market integration are crucially affected by the extent to which countries are open to trade. In this paper we build a multi-country dynamic general equilibrium model with trade in goods and labor mobility across countries to study and quantify the economic effects of trade and labor market integration. In our model trade is costly and features households of different skills and nationalities facing costly forward-looking relocation decisions. We use the EU Labour Force Survey to construct migration flows by skill and nationality across 17 countries for the period 2002-2007. We then exploit the timing variation of the 2004 EU enlargement to estimate the elasticity of migration flows to labor mobility costs, and to identify the change in labor mobility costs associated to the actual change in policy. We apply our model and use these estimates, as well as the observed changes in tariffs, to quantify the effects from the EU enlargement. We find that new member state countries are the largest winners from the EU enlargement, and in particular unskilled labor. We find smaller welfare gains for EU-15 countries. However, in the absence of changes to trade policy, the EU-15 would have been worse off after the enlargement. We study even further the interaction effects between trade and migration policies and the role of different mechanisms in shaping our results. Our results highlight the importance of trade for the quantification of the welfare and migration effects from labor market integration.
Itskhoki, Oleg, and Benjamin Moll. "Optimal Development Policies With Financial Frictions." Econometrica 87.1 (2019): 139-173.
Abstract: Is there a role for governments in emerging countries to accelerate economic development by intervening in product and factor markets? To address this question, we study optimal dynamic Ramsey policies in a standard growth model with financial frictions. The optimal policy intervention involves pro‐business policies like suppressed wages in early stages of the transition, resulting in higher entrepreneurial profits and faster wealth accumulation. This, in turn, relaxes borrowing constraints in the future, leading to higher labor productivity and wages. In the long run, optimal policy reverses sign and becomes pro‐worker. In a multi‐sector extension, optimal policy subsidizes sectors with a latent comparative advantage and, under certain circumstances, involves a depreciated real exchange rate. Our results provide an efficiency rationale, but also identify caveats, for many of the development policies actively pursued by dynamic emerging economies.
推荐语by匿名：产业政策问题一直备受关注，那么存在金融摩擦情景下的什么才是最优的产业政策？可以参考这个框架讨论不同的最优产业政策问题。
Paul Dolfen, Liran Einav, Peter J. Klenow, Benjamin Klopack, Jonathan D. Levin, Laurence Levin, Wayne Best (2019).”Assessing the Gains from E-Commerce.” NBER Working Paper.
Abstract: E-Commerce represents a rapidly growing share of consumer spending in the U.S. We use transactions-level data on credit and debit cards from Visa, Inc. between 2007 and 2017 to quantify the resulting consumer surplus. We estimate that E-Commerce spending reached 8% of consumption by 2017, yielding consumers the equivalent of a 1% permanent boost to their consumption, or over $1,000 per household. While some of the gains arose from saving travel costs of buying from local merchants, most of the gains stemmed from substituting to online merchants. Higher income cardholders gained more, as did consumers in more densely populated counties.
（推荐人：兰小欢老师）
