The Economics of Housing Supply


chart by Smallman12q

Housing economists Edward L. Glaeser and Joseph Gyourko have posted The Economic Implications of Housing Supply to SSRN (behind a paywall but you can find a slightly older version of the paper here). The abstract reads,

In this essay, we review the basic economics of housing supply and the functioning of US housing markets to better understand the distribution of home prices, household wealth and the spatial distribution of people across markets. We employ a cost-based approach to gauge whether a housing market is delivering appropriately priced units. Specifically, we investigate whether market prices (roughly) equal the costs of producing the housing unit. If so, the market is well-functioning in the sense that it efficiently delivers housing units at their production cost. Of course, poorer households still may have very high housing cost burdens that society may wish to address via transfers. But if housing prices are above this cost in a given area, then the housing market is not functioning well – and housing is too expensive for all households in the market, not just for poorer ones. The gap between price and production cost can be understood as a regulatory tax, which might be efficiently incorporating the negative externalities of new production, but typical estimates find that the implicit tax is far higher than most reasonable estimates of those externalities.

The paper’s conclusions, while a bit technical for a lay audience, are worth highlighting:

When housing supply is highly regulated in a certain area, housing prices are higher and population growth is smaller relative to the level of demand. While most of America has experienced little growth in housing wealth over the past 30 years, the older, richer buyers in America’s most regulated areas have experienced significant increases in housing equity. The regulation of America’s most productive places seems to have led labor to locate in places where wages and prices are lower, reducing America’s overall economic output in the process.

Advocates of land use restrictions emphasize the negative externalities of building. Certainly, new construction can lead to more crowded schools and roads, and it is costly to create new infrastructure to lower congestion. Hence, the optimal tax on new building is positive, not zero. However, there is as yet no consensus about the overall welfare implications of heightened land use controls. Any model-based assessment inevitably relies on various assumptions about the different aspects of regulation and how they are valued in agents’ utility functions.

Empirical investigations of the local costs and benefits of restricting building generally conclude that the negative externalities are not nearly large enough to justify the costs of regulation. Adding the costs from substitute building in other markets generally strengthens this conclusion, as Glaeser and Kahn (2010) show that America restricts building more in places that have lower carbon emissions per household. If California’s restrictions induce more building in Texas and Arizona, then their net environmental could be negative in aggregate. If restrictions on building limit an efficient geographical reallocation of labor, then estimates based on local externalities would miss this effect, too.

If the welfare and output gains from reducing regulation of housing construction are large, then why don’t we see more policy interventions to permit more building in markets such as San Francisco? The great challenge facing attempts to loosen local housing restrictions is that existing homeowners do not want more affordable homes: they want the value of their asset to cost more, not less. They also may not like the idea that new housing will bring in more people, including those from different socio-economic groups.

There have been some attempts at the state level to soften severe local land use restrictions, but they have not been successful. Massachusetts is particularly instructive because it has used both top-down regulatory reform and incentives to encourage local building. Massachusetts Chapter 40B provides builders with a tool to bypass local rules. If developers are building enough formally-defined affordable units in unaffordable areas, they can bypass local zoning rules. Yet localities still are able to find tools to limit local construction, and the cost of providing price-controlled affordable units lowers the incentive for developers to build. It is difficult to assess the overall impact of 40B, especially since both builder and community often face incentives to avoid building “affordable” units. Standard game theoretic arguments suggest that 40B should never itself be used, but rather work primarily by changing the fallback option of the developer. Massachusetts has also tried to create stronger incentives for local building with Chapters 40R and 40S. These parts of their law allow for transfers to the localities themselves, so builders are not capturing all the benefits. Even so, the Boston market and other high cost areas in the state have not seen meaningful surges in new housing development.

This suggests that more fiscal resources will be needed to convince local residents to bear the costs arising from new development. On purely efficiency grounds, one could argue that the federal government provide sufficient resources, but the political economy of the median taxpayer in the nation effectively transferring resources to much wealthier residents of metropolitan areas like San Francisco seems challenging to say the least. However daunting the task, the potential benefits look to be large enough that economists and policymakers should keep trying to devise a workable policy intervention. (19-20)

Regulation and Housing Supply

Gyourko and Molloy have posted Regulation and Housing Supply to SSRN.  Unfortunately, it is behind a paywall (although it is also available at NBER if your library has access and an earlier draft can be found here). The abstract of this book chapter states that it reviews the scholarly literature on the causes and effects of local government regulation that “influences the amount, location, and shape of residential development.” The abstract continues,

We begin with a discussion of how researchers measure regulation empirically, which highlights the variety of methods that are used to constrain development. Many theories have been developed to explain why regulation arises, including the role of homeowners in the local political process, the influence of historical density, and the fiscal and exclusionary motives for zoning. As for the effects of regulation, most studies have found substantial effects on the housing market. In particular, regulation appears to raise house prices, reduce construction, reduce the elasticity of housing supply, and alter urban form. Other research has found that regulation influences local labor markets, and household sorting across communities. Finally, we discuss the welfare implications of regulation. Although the large positive externalities of some specific rules are clear, the benefits of more general forms of regulation are very difficult to quantify. On balance, a few recent studies suggest that the overall efficiency losses from binding constraints on residential development could be quite large.
Land use geeks are familiar with Gyourko’s analysis of land use regulation, but many non-economists are not.  Even if they are, they often give it short shrift. I found the extension of their analysis beyond the borders of the U.S. interesting:
In theory, the availability of buildable land might not constrain the supply of housing units if housing could be constructed as densely as necessary to meet demand. But in most places in the U.S.—and indeed around the world—local land use policy imposes limits on residential development that restrict the size and type of housing units that can be built on a given amount of land. These restrictions add extra costs to a construction project, creating a wedge between the sales price of a house and the cost of buying the land and building the structure. (3)
As communities struggle with housing affordability, the link between land use regulation and housing costs is one that should not be ignored.