ایجاد اشتغال و ساخت و ساز مسکن: محدودیت در رشد اشتغال ناحیه شهری

Differences in the supply of housing generate substantial variation in house prices across the United States. Because house prices influence migration, the elasticity of housing supply also has an important impact on local labor markets. I assemble evidence on housing supply regulations and examine their effect on metropolitan area housing and labor market dynamics. Locations with relatively few barriers to construction experience more residential construction and smaller increases in house prices in response to an increase in housing demand. Furthermore, housing supply constraints alter local employment and wage dynamics in locations where the degree of regulation is most severe.

A growing literature argues that labor migration is one of the primary mechanisms through which metropolitan areas adjust to changes in local economic conditions (Blanchard and Katz, 1992; Gallin, 2004; Topel, 1986). Prospective migrants choose a location by comparing the benefit to living in each area to the cost of moving. Because housing is a large share of the household budget, house prices have an important effect on the relative value of wages across geographic areas.1 As a result, areas with high house prices will attract fewer migrants holding other factors constant (Gabriel et al., 1993; Johnes and Hyclak, 1999). Because housing markets influence migration, local employment growth depends critically on the capacity of the construction industry to accommodate increases in housing demand. In places where residential construction responds to new demand without difficulty, workers will move into the area with little change in house prices. In contrast, if new construction is constrained, an increase in demand will lead mostly to higher house prices, with little change in employment. Thus, the elasticity of housing supply is a key factor in determining how labor markets adjust to changes in local economic conditions.2 Although changes in the housing supply are not the only way in which an area can adjust to a change in local labor demand, the correlation between changes in employment and new construction is strong. Controlling for year and metropolitan area fixed effects, a simple OLS regression of annual log changes in employment on annual log changes in the housing stock yields a coefficient of 0.57 (with a standard error of 0.03).3,4 Therefore, growing cities must confront the issue of where new workers will live. In this paper, I explore the effect of the housing supply on metropolitan area labor markets. To determine the elasticity of housing supply in individual metropolitan areas, I assemble evidence from six different sources of information on local land use policy. This new index reveals considerable heterogeneity in the extent of regulation across locations, and I find that areas with a larger degree of regulation experienced less residential construction and larger house price increases than less regulated locations from 1980 to 2000. In addition to these effects on local housing markets, I develop a simple model to show how the elasticity of housing supply (and consequently the degree of housing supply regulation) should also impact local labor markets. Specifically, a labor demand shock should result in lower employment growth, higher wages and higher house prices in places with an inelastic housing supply. Consistent with this theory, the long-run response of employment to an increase in labor demand is about 20 percent lower in metropolitan areas with a high degree of housing supply regulation.

Land use restrictions and other government regulations have a substantial impact on housing and labor market dynamics in metropolitan areas across the United States. These regulations lower the elasticity of housing supply, consequently altering relative differences in house prices and patterns of labor migration across locations. As a result, employment growth is lower in places where the housing supply is more constrained. The empirical analysis in this paper showed that locations with a larger degree of housing supply regulation experience less residential construction and larger increases in house prices in response to an increase in labor demand. Moreover, housing supply regulations have a lasting effect on metropolitan area employment. In the long run, an increase in labor demand results in considerably lower employment in metropolitan areas with a low elasticity of housing supply. These results demonstrate that the interaction between the housing supply and local labor markets is an important determinant of regional patterns of employment growth. The impact of housing supply regulations likely extends beyond the effects on employment, wages and house prices discussed here. For example, as places with a large degree of regulation experience rising house prices, the composition of the population within these metropolitan areas may change. Because young people and minorities have a higher propensity to move (US Census Bureau, 2004), areas with many housing supply constraints may end up with a smaller share of people in these groups. Furthermore, high house prices may mean that only rich households can afford to move into a location while poorer households are forced out, leading to higher income inequality across locations (Gyourko et al., 2006). An additional effect of changing the composition of the local population may be that the skills of the local workforce will change, thereby altering the industrial composition of local firms as well.Of course, policies that restrict the expansion of the housing supply are not without benefits. By enforcing quality standards for residential housing units and reducing the negative externalities associated with crowding and undesirable land uses, these regulations can make some local residents better off. The goal of this paper was not to emphasize the negative consequences of housing supply restrictions, but rather to point out that the costs of housing supply regulation will be underestimated if the effects on the labor market are not taken into account. Thus, discussions of land use policy are not complete without considering their implications for labor markets and employment growth in addition to their impact on housing markets.