Does the U.S. tax treatment of housing promote suburbanization and central city decline?

This paper examines the role of U.S. housing-related tax expenditures in creating incentives for decentralization and encouraging residential sorting by income and central city decline. Tax expenditures associated with the deductibility of mortgage interest and property taxes make housing less expensive relative to other goods and, hence, increase the quantity of housing and residential land purchased and lower the density of urban areas. Because the tax expenditures increase with income and the consumption of housing services, they lower the cost of geographic sorting by income typically associated with exclusionary zoning and other land- market imperfections. A direct consequence of this sorting process is that housing-related tax expenditures are concentrated in communities with the highest incomes and house values. These effects do not arise simply because of housing-tax policies alone, but rather from the interaction of these policies and other factors that affect local real e state markets, such as zoning or fixed housing capital stocks. Three models are developed to formally analyze these issues. In the authors' base case model in which there are no land-use constraints and local amenities are fixed, tax deductions related to home ownership result in population decentralization within the metropolitan area and a less dense central city, but do not induce sorting by income. Moreover, land prices in the city increase because the subsidy increases the aggregate demand for housing in all communities. Thus, the mere presence of the federal housing tax expenditures increases decentralization, but cannot generate America's patterns of income sorting and central city decline. These conclusions change in an important way in the authors' second model in which a land-use constraint, such as the type of minimum lot-size zoning prevalent in the suburbs, is introduced. In this case, the housing subsidies foster the separation of the rich from the poor. Inco me sorting results, and consequently, there is an increasing concentration of the poor in the central city. However, there still is no weakening of prices in city land markets in this model. The third and final model endogenizes the production of local amenities in the sense that they are made an increasing function of community income. In this case, three characteristics common to American urban form result: population decentralization within the metropolitan area, increased concentration of the poor in the urban core, and weak city land markets. These results indicate that America's current urban form reflects, at least in part, incentives arising from the interaction of the national tax and local zoning systems, rather than unique American tastes for low-density living environments.