Urban search models under high-relocation costs. Theory and application to spatial mismatch

We develop a search-matching model in which mobility costs are so high that it is too costly for workers to relocate when a change in their employment status occurs. We show that, in equilibrium, wages increase with distance to jobs and commuting costs because firms need to compensate the transportation cost difference between the employed and unemployed workers at each location in the city. We also show that the equilibrium land rent is negatively affected by the unemployment benefit because an increase in the latter induce firms to create less jobs, which, in turn, reduces the competition in the land market. We then use this model to provide a mechanism for the observed spatial mismatch between where black workers live and where jobs are. We finally show that a transportation policy consisting in subsidizing the commuting costs of black workers can increase job creation and reduce unemployment if the level of the subsidy is set at a sufficiently high level.     

The effects of an equiproportional transport improvement in a fully-closed Monocentric City

This paper investigates the effects of an equiproportional transport improvement (or, equivalently, a fall in the ‘price’ of transportation) in a fully-closed monocentric city. It focuses on the impact of the improvement on aggregate land rents, differential land rents, and aggregate transport costs. The elasticity of the aggregate transport demand is related to the elasticity of substitution between land and all other goods and the compensated elasticity of demand for land.     

Income taxes and urban spatial structure

This paper examines the impact of an income tax in a monocentric city where households equilibriate their allocation of time between work, commuting, and leisure. An increase in the income tax rate lowers the implicit value of time, and hence transportation costs. “Compensated equilibrium” comparative statics analysis shows that under certain conditions, this results in a larger, more dispersed urban area, with lower land rents at the city center and less population within any given distance from the center. The welfare effect of an income tax rate change is also studied, and an expression for the marginal excess burden is derived. The income tax produces welfare losses both because it induces substitution in favor of leisure and in favor of travel—the latter accompanied by excessive spatial dispersion and consumption of space. The marginal excess burden depends not only on the compensated demand elasticity for leisure, but also on that for space. Finally, the problem of benefit measurement for transportation projects in this tax-distorted spatial economy is examined. Benefit measures should be deflated to adjust for the fact that further transportation improvements lead to reduction of land use intensity, exacerbating the problem of spatial resource misallocation in an already excessively dispersed urban area.     

Equilibrium search unemployment with explicit spatial frictions

Assuming that job search efficiency decreases with distance to jobs, workers' location in a city depends on spatial elements such as commuting costs and land prices and on labour elements such as wages and the matching technology. In the absence of moving costs, we show that there exists a unique equilibrium in which employed and unemployed workers are perfectly segregated but move at each employment transition. We investigate the interactions between the land and the labour market equilibrium and show under which condition they are interdependent. When relocation costs become positive, a new zone appears in which both the employed and the unemployed co-exist and are not mobile. We demonstrate that the size of this area goes continuously to zero when moving costs vanish. Finally, we endogeneize search effort, show that it negatively depends on distance to jobs and that long and short-term unemployed workers coexist and locate in different areas of the city.     

Endogenous job destruction and job matching in cities

We propose a spatial search-matching model where both job creation and job destruction are endogenous. Workers are ex ante identical but not ex post since their jobs can be hit by a technological shock which decreases their productivity. They reside in a city, and commuting to the job center involves both pecuniary and time costs. As a result, workers with high wages are willing to live closer to jobs to save on time commuting costs. We show that, in equilibrium, there is a one-to-one correspondence between the productivity space and the urban location space. Workers with high productivities and wages reside close to jobs, have low per distance commuting costs and pay high land rents. We also show that higher per distance commuting costs and higher unemployment benefits lead to more job destruction.     

Firm suburbanization and urban subcenters

The theory of firm location within an urban area is extended to consider a city in which firms can export their output via a suburban terminal as well as via the usual CBD terminal. Firms benefit from suburbanization since freight transport costs are reduced and since they can pay lower wages, but labor may be scarce in the suburbs. This forces suburban firms to readjust their wages, causing some workers to out-commute and giving all workers an incentive to relocate. The existence of an employment subcenter under labor scarcity conditions is shown to cause household utility levels to rise, the size of the metropolitan area to increase, and overall urban land value to change indeterminately. Finally, determination of the optimal location for a suburban terminal is considered.     

Workforce location and equilibrium unemployment in a duocentric economy with matching frictions

This article examines unemployment disparities and efficiency in a duocentric city where workers are non-uniformly distributed between the two job centers. We introduce commuting costs and search-matching frictions to deal with the spatial mismatch between workers and firms. In a decentralized economy job-seekers do not internalize a composition externality they impose on all the unemployed. With symmetric job centers, a change in the distribution of the workforce can lead to asymmetric equilibrium outcomes. We calibrate the model for Los Angeles and Chicago Metropolitan Statistical Areas. Simulations suggest that changes in the workforce distribution have non-negligible effects on unemployment rates, wages, and net output, but cannot be the unique explanation of a substantial mismatch problem.     

Urban models of race discrimination

This paper presents two models of discriminatory behavior by whites in an urban context. In the first, both the black and white populations of the city are assumed fixed and the model yields the counterintuitive prediction that white prejudice makes blacks better off. In the second model, blacks and whites both migrate freely between cities when by doing so they can raise their welfare levels. In this case the model predicts that increases in whites' taste for discrimination cause racially mixed cities to become less mixed; whites move out and blacks move in. The remaining whites retreat to an isolated suburban outer ring where they are compensated for remaining in the mixed city by consuming more land than whites in non- mixed cities. From a welfare standpoint, racially mixed cities are shown to be inefficient since they are more spread out and travel costs are higher.     

A model of population distribution,traffic congestion,and neighborhood crowding in a circular city

An idealized static equilibrium model of a circularly symmetric city is presented. The model allows one to compute the spatial distribution of residences, given certain simple and plausible assumptions about the “costs” of transport, housing and neighborhood crowding. The model is chosen so as to guarantee that in first approximation, the residential population distribution which would be considered optimal by a perfect planner is identical to the distribution reached in a push-shove, laissez-faire equilibrium. This aspect of the construction is shown to be related in a simple way to the familiar “external diseconomy” situation in which a free resource is allocated among alternative uses by equating average, rather than marginal products. The existence of an infinite class of models in which the associated planner's optimum and laissez-faire equilibria are equivalent follows naturally from the standard theory of the private and social costs of highway congestion. The model leads naturally to exponentially falling population distributions which exhibit an “urban-suburban” dichotomy, to a particular overall city size, and to an optimal allocation of land between transport and residential uses.     

Local income taxation in an urban area

This paper indicates the response of a metropolitan area to the levying of a local income tax. The analysis is focused on a central city and its surrounding suburbs but allows for migration to and from the metropolitan area. Of primary interest are the spatial effects of local income taxation and the associated welfare costs derived from additional transportation expenditures. The analysis indicates the forms of compensation to central city high-income households for the fiscal deficit they bear. Changes in wage rates and land rentals are derived and the question of full capitalization is considered.     

Ageing and employability. Evidence from Belgian firm-level data

The Belgian population is ageing due to demographic changes, so does the workforce of firms active in the country. Such a trend is likely to remain for the foreseeable future. And it will be reinforced by the willingness of public authorities to expand employment among individuals aged 50 or more. But are older workers employable? The answer depends to a large extent on the gap between older workers’ productivity and their cost to employers. To address this question we use a production function that is modified to reflect the heterogeneity of labour with workers of different age potentially diverging in terms of marginal products. Using unique firm-level panel data we produce robust evidence on the causal effect of ageing on productivity (value added) and labour costs. We take advantage of the panel structure of data and resort to first-differences to deal with a potential time-invariant heterogeneity bias. Moreover, inspired by recent developments in the production function estimation literature, we also address the risk of simultaneity bias (endogeneity of firm’s age-mix choices in the short run) using (1) the structural approach suggested by Ackerberg et al. Structural identification of production functions. Department of Economics, UCLA, (2006), (2) alongside more traditional system-GMM methods (Blundell and Bond in J Econom 87:115–143, 1998) where lagged values of labour inputs are used as instruments. Our results indicate a negative impact of larger shares of older workers on productivity that is not compensated by lower labour costs, resulting in a lower productivity-labour costs gap. An increment of 10 %-points of their share causes a 1.3–2.8 % contraction of this gap. We conduct several robustness checks that largely confirm this result. This is not good news for older individuals’ employability and calls for interventions in the Belgian private economy aimed at combating the decline of productivity with age and/or better adapting labour costs to age-productivity profiles.     

Does City Structure Affect Job Search and Welfare?

We develop a model in which workers' search efficiency is negatively affected by access to jobs. Workers' location in a city is endogenous and reflects a trade-off between commuting costs and the surplus associated with search. Different configurations emerge in equilibrium; notably, the unemployed workers may reside far away (segregated city) or close to jobs (integrated city). We prove that there exists a unique and stable market equilibrium in which both land and labor markets are solved for simultaneously. We find that, despite inefficient search in the segregated city equilibrium, the welfare difference between the two equilibria is not so large due to differences in commuting costs. We also show how a social planner can manipulate wages by subsidizing/taxing the transport costs and can accordingly restore the efficiency.     

SPATIAL PRICE EQUILIBRIUM AND THE TRANSPORT SECTOR: A TRADE‐CONSISTENT SCGE MODEL

In spatial computable general equilibrium models, interregional trade ought to play an important role in determining the spatial price equilibrium. Although the Armington assumption is commonly employed to describe cross‐hauling, many of the existing models do not explicitly consider the behavior of transport firms. This paper presents a framework that is compatible with the Armington assumption and explicitly considers transport activities. In the model, the trade coefficient takes the form of a potential function, and the equilibrium market price becomes similar to the price index in the context of new economic geography. The features of the model are investigated by using the minimal setting, which comprises two nontransport sectors and three regions. Because transport costs are given exogenously, the commodity prices are determined relative to them. The model can be described as a system of homogeneous equations, where an output in one region can arbitrarily be determined similarly as a price in the Walrasian equilibrium.     

Labour market oligopsonistic competition: The effect of worker immobility on wages

We suggest that firms in a local labour market may be able to exploit worker mobility costs and offer immobile workers wages that are lower than their marginal product. If so, the ability of employers to exploit worker immobility in setting wages would decline in the competitiveness of the local labour market. We test this intuition using a measure of individual mobility costs and measures of local labour market competition. Our findings suggest that worker immobility causes substantial wage variation across workers in small, weakly competitive markets, and in occupations where wages are individually bargained.     

The effect of international firm mobility on wages and unemployment

Although the increase in international firm mobility is well documented, its effects on macroeconomic aggregates and the labour market remain controversial. Multinational enterprises (MNEs) benefit from an international outside option during wage bargaining, leading to a decrease in average wages. However, a strategic incentive to hire extra workers in a foreign (home) plant in order to reduce wages in the home (foreign) plant has an indirect positive effect on wages due to spillovers resulting from an increased demand for labour. In a framework of frictional unemployment, permitting MNEs leads to a decrease in unemployment. Abstracting from transport and plant fixed costs, MNEs lead to higher wages. Including transport and plant costs generally leads to lower wages, though the effects are small. The strategic hiring effect is important in mitigating the fall in wages.     

The Henry George Theorem in a second-best world

The Henry George Theorem (HGT) states that, in first-best economies, the fiscal surplus of a city government that finances the Pigouvian subsidies for agglomeration externalities and the costs of local public goods by a 100% tax on land is zero at optimal city sizes. We extend the HGT to distorted economies where product differentiation and increasing returns are the sources of agglomeration economies and city governments levy property taxes. Without relying on specific functional forms, we derive a second-best HGT that relates the fiscal surplus to the excess burden expressed as an extended Harberger formula.     

Transport subsidies, system choice, and urban sprawl

This paper analyzes the effect of transport subsidies on the spatial expansion of cities, asking whether such subsidies are a source of undesirable urban sprawl. Even though the cost-reducing effect of transport subsidies is offset by a higher general tax burden (which reduces the demand for space), the analysis shows that subsidies nevertheless lead to spatial expansion of cities. If the transport system exhibits constant returns to scale, the subsidies are inefficient, making the urban expansion they entail undesirable. The paper also studies transport “system choice,” with the city portrayed as selecting its transport system from along a continuum of money cost/time cost choices. The analysis shows that subsidies inefficiently bias choice in the direction of a high money cost/low time cost option. Lastly, the paper considers system choice in a city with rich and poor groups, showing that the rich favor a system with a high money cost and low time cost, but that their choice, if implemented, leads to a city whose spatial size is smaller than optimal. Thus, rich control of system choice does not lead to urban sprawl.     

Acquisition of skills, labor subsidies, and agglomeration of firms

The paper develops an analytically solvable model of new economic geography in which agglomeration of firms is caused by workers' investment in the acquisition of skills. Skilled workers earn high wages and have a large demand for goods. Since firms are attracted towards the demand, they locate at proximity of skilled workers. More workers invest in the acquisition of skills when more firms ask for these skills. Consequently, partial or full agglomeration of firms may be the location equilibrium. We also show that a reduction in transport costs increases the regional governments' incentives to subsidize the acquisition of skills.     

The origin of spatial interaction

This paper uses spatial empirical methods to detect and analyze trade patterns in a historical data set on Chinese rice prices. Our results suggest that spatial features were important for the expansion of interregional trade. Geography dictates, first, over what distances trade was possible in different regions, because the costs of ship transport were considerably below those for land transport. Spatial features also influence the direction in which a trading network is expanding. Moreover, our analysis captures the impact of new trade routes both within and outside the trading areas.     

Residential location and scheduling of work hours

The choices of residential location and work-start time in a monocentric city are examined. Workers may choose to live either near or far from the city center, where work takes place; they may also choose to start at a peak work-start time with many other workers, or to start at an off-peak time with fewer workers. The theoretical results indicate that the relation between choice of work-start time and location depends upon the effects of staggered work hours on income and the transportation technology in the city.