Treb Allen, Costas Arkolakis, and Yuta Takahashi. 2020. “Universal Gravity.”Journal of Political Economy, 128(2):393-433. (DOI: 10.1086/704385)

摘要

We study the theoretical properties and counterfactual predictions of a large class of general equilibrium trade and economic geography models. By combining aggregate factor supply and demand functions with market-clearing conditions, we prove that existence, uniqueness, and—given observed trade flows—the counterfactual predictions of any model within this class depend only on the demand and supply elasticities (“gravity constants”). Using a new “model-implied” instrumental variables approach, we estimate these gravity constants and use these estimates to compute the impact of a trade war between the United States and China.

推介理由

Shows key theoretical properties & predictions of large class of trade/geography gravity models depend on 2 parameters: elasticities of supply and demand. Proposes IV estimation strategy relying on GE structure.

Ambrus, Attila, Erica Field, and Robert Gonzalez. 2020. Loss in the Time of Cholera: Long-Run Impact of a Disease Epidemic on the Urban Landscape. American Economic Review, 110 (2): 475-525. (DOI: 10.1257/aer.20190759)

摘要

How do geographically concentrated income shocks influence the long-run spatial distribution of poverty within a city? We examine the impact on housing prices of a cholera epidemic in one neighborhood of nineteenth century London. Ten years after the epidemic, housing prices are significantly lower just inside the catchment area of the water pump that transmitted the disease. Moreover, differences in housing prices persist over the following 160 years. We make sense of these patterns by building a model of a rental market with frictions in which poor tenants exert a negative externality on their neighbors. This showcases how a locally concentrated income shock can persistently change the tenant composition of a block.

推介理由

1854 London: prices fell in blocks served by well transmitting cholera. Differences persist. Model: tenants change as contracts expire, negative externality of poor tenants, shock makes landlords persistently target poor.

Konstantin Büchel, Maximilian v.Ehrlich. 2020. “Cities and the structure of social interactions: Evidence from mobile phone data.” Journal of Urban Economics, 119: 103276. (DOI: 10.1016/j.jue.2020.103276)

摘要

The impact of telecommunication technologies on the role of cities depends on whether these technologies and face-to-face interactions are substitutes or complements. We analyze anonymized mobile phone data to examine how distance and population density affect calling behavior. Exploitingan exogenous change in travel times as well as permanent relocations of individuals, we find that distance is highly detrimental to link formation. Mobile phone usage significantly increases with population density even when spatial sorting is accounted for. This effect is most pronounced for local interactions betweenindividuals in the same catchment area. This indicates that face-to-face interactions and mobile phone calls are complementary to each other, so that mobile phone technology may even increase the dividends of density.

推介理由

More sociable individuals sort into cities. Even after accounting for sorting, those in denser areas call each other more often & longer, suggesting complementarity between face-to-face and phone interactions.

Felipe Carozzi.2020. “Credit Constraints and the Composition of Housing Sales. Farewell to First-Time Buyers?”Journal of European Economic Association, 18(3):1196-1237. (DOI: 10.1093/jeea/jvz017)

摘要

During the housing bust of 2008–2009, housing prices and transaction volumes fell across the United Kingdom. Although the drop in prices was similar across housing types, transaction volumes fell more for units at the lower end of the market. I document this fact and provide panel and instrumental variable estimates showing its link with tightening credit conditions in England and Wales during 2008. I then use an overlapping-generation framework to relate the change in the composition of sales with the reduction in loan-to-value ratios by British banks and to derive additional predictions. As down-payment requirements increase, young households with scarce financial resources are priced out by older owners who retain their previous houses as rental properties when trading up. Recent changes in aggregate housing tenure, disaggregated changes in renting, and sales in areas with different age compositions, are consistent with these predictions. The results presented here show how the composition of sales changes over the housing cycle and may inform ongoing policy discussions about reduced access to home-ownership by the young.

推介理由

Shows how credit constraints affect composition of housing sales & access to home-ownership by the young. Neat model of housing markets as ladders with young in cheap units, possibly trading up as they age, post-2008 UK evidence.

Harari, Mariaflavia. 2020. Cities in Bad Shape: Urban Geometry in India. American Economic Review, 110 (8): 2377-2421. (DOI: 10.1257/aer.20171673)

摘要

The spatial layout of cities is an important feature of urban form, highlighted by urban planners but overlooked by economists. This paper investigates the causal economic implications of city shape in India. I measure cities' geometric properties over time using satellite imagery and historical maps. I develop an instrument for urban shape based on geographic obstacles encountered by expanding cities. Compact city shape is associated with faster population growth and households display positive willingness to pay for more compact layouts. Transit accessibility is an important channel. Land use regulations can contribute to deteriorating city shape.

推介理由

City shape matters. More compact (circular) Indian cities grow faster (IVs compactness with mechanical expansion + geographic constraints). Compactness affects road network, location patterns, quality of life. Regulations affect shape.

Stephan Heblich,  Stephen J Redding,  Daniel M Sturm.2020. “The Making of the Modern Metropolis: Evidence from London.”Quarterly Journal of Economics, 135(4):2059-2133. (DOI: 10.1093/qje/qjaa014)

摘要

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.

推介理由

Uses quantitative urban model and spatially disaggregated data for London 1801-1921 to explore how steam railways triggered workplace-residence separation, enabling substantial agglomeration in production & residence.

Crocker H. Liu, Stuart S. Rosenthal, William C. Strange. 2020. “Employment density and agglomeration economies in tall buildings.”Regional Science and Urban Economics, 84：103555.  (DOI: 10.1016/j.regsciurbeco.2020.103555)

摘要

This paper examines vertical patterns of employment density and agglomeration economies within tall buildings. Theory suggests that vertical density should depend on the interplay of street access, height-related amenities, and productivity. Based on suite level data, we show that density patterns are u-shaped, with high density at ground level and high floors. Furthermore, factors associated with productivity, including nearby employment and firm-specific characteristics, have positive effects on employment density. Vertical density patterns are consistent with productivity spillovers that are strongest on a company’s floor and attenuate rapidly with vertical distance. Similar evidence is obtained based on sales for law firms.

推介理由

Agglomeration in tall buildings depends on street access, height amenities & productivity. Ground & high floors most valuable. Density & law firm sales indicate strong same-floor spillovers quickly attenuating vertically.

Daniel Oto-Peralías.2020.“Frontiers, warfare and economic geography: The case of Spain.”Journal of Development Economics, 146:102511. (DOI:10.1016/j.jdeveco.2020.102511)

摘要

This paper investigates the potential of frontiers to shape the economic geography of countries. I focus on the case of Spain to explore how historical frontier warfare affects the colonization of the territory and the distribution of the population across the space. Exploiting a spatial discontinuity in military insecurity during the Christian colonization of central Spain in the Middle Ages, my findings suggest that medieval frontier warfare heavily conditioned the settlement of the territory, resulting in a sparse occupation of the space, low settlement density and high population concentration. These initial features of the colonization process were already visible in the early 16th century and have persisted to this day, with potential negative consequences for economic development.

推介理由

Explores origins of settlement patterns exploiting spatial discontinuity in insecurity in medieval Spain. Frontier warfare encourages population concentration in few livestock-oriented (vs. agriculture) settlements, strong persistence.

Owens, Raymond III, Esteban Rossi-Hansberg, and Pierre-Daniel Sarte. 2020. Rethinking Detroit. American Economic Journal: Economic Policy, 12 (2): 258-305. (DOI: 10.1257/pol.20180651)

摘要

This paper studies the urban structure of Detroit—one that is clearly not optimal for its size—which features a business district immediately surrounded by largely vacant neighborhoods. A model is presented where residential externalities lead to multiple equilibria at the neighborhood level. Specifically, neighborhood development requires the coordination of developers and residents, without which it may remain vacant even with sound fundamentals. Given this mechanism, existing strategic visions to revitalize Detroit are evaluated within a quantitative spatial model that can rationalize Detroit's current allocations. Alternative plans that rely on development guarantees are also considered and shown to yield better outcomes.

推介理由

Detroit CBD surrounded by vacant land through model with residential externalities leading to coordination problem, evaluates development guarantees & other alternatives.

Piazzesi, Monika, Martin Schneider, and Johannes Stroebel. 2020. Segmented Housing Search. American Economic Review, 110 (3): 720-59. (DOI:10.1257/aer.20141772)

摘要

We study housing markets with multiple segments searched by heterogeneous clienteles. In the San Francisco Bay Area, search activity and inventory covary negatively across cities, but positively across market segments within cities. A quantitative search model shows how the endogenous flow of broad searchers to high-inventory segments within their search ranges induces a positive relationship between inventory and search activity across segments with a large common clientele. The prevalence of broad searchers shapes the response of housing markets to localized supply and demand shocks. Broad searchers help spread shocks across many segments and reduce their effect on local market activity.

推介理由

Housing search model with many segments, agents with different search ranges, broad searchers that narrow down by segment inventory. Helps think about Beveridge curve, scope & connectedness in housing markets.