In 1950, a median-income American family could buy a median-priced home for roughly two to three times annual income. By 2024, that ratio in San Francisco had reached approximately 11 to 1, in Los Angeles 9 to 1, and in New York 7 to 1. London's ratio exceeded 10 to 1. Sydney's exceeded 12 to 1. This is not primarily a story about rising incomes failing to keep pace with general price inflation, or about construction becoming prohibitively expensive, or about too many people wanting to live in cities. It is primarily a story about a political failure: the systematic prevention of housing construction in the places where people most want to live, sustained over decades by the organized interests of those who already own homes.
The human costs are not abstract. Workers who cannot afford to live near productive urban labor markets either endure crushing commutes, accept lower-paying jobs in less expensive areas, or do not move at all — trapped in declining regions where opportunities are scarce. Young people delay family formation because they cannot afford the space. Low-income renters are displaced by rising costs and pushed further from jobs, schools, and services. Homelessness in expensive cities reflects the extreme end of a housing market that has failed to allocate shelter efficiently. Raj Chetty's research at Harvard has documented that high housing costs in productive cities function as a barrier to upward mobility: children raised in high-opportunity areas have dramatically better life outcomes, but those areas are increasingly available only to those who were already wealthy.
The economics of the housing crisis are, in one sense, simple: prices rise when demand exceeds supply, and supply in high-demand cities has been severely constrained by regulation. But the political economy is complex. The restrictions on supply exist because they serve the interests of those who already own homes — a politically powerful, high-voting constituency who benefit financially from scarcity. Understanding why housing is so expensive requires understanding both the mechanism and why the mechanism persists despite its social costs.
"Land use regulations in New York, San Francisco, and San Jose have reduced aggregate US GDP by 2.0 percentage points. If these cities adopted the median land use rules of other US cities, these metro areas could expand their workforces and lead to a substantial reallocation of workers to high-productivity areas." -- Chang-Tai Hsieh and Enrico Moretti, Housing Constraints and Spatial Misallocation (2019)
Key Definitions
Land use regulation: Government rules governing what can be built on land. Includes zoning designations (residential, commercial, industrial), density limits, height restrictions, setback requirements, parking minimums, and design standards.
Single-family zoning: Zoning that restricts residential land to detached single-family homes, prohibiting apartments, condominiums, duplexes, or accessory dwelling units. Covers the majority of residential land in most large American cities.
Supply elasticity: The degree to which housing supply responds to price increases. In elastic markets, rising prices quickly trigger new construction, moderating price increases. In inelastic markets, regulatory barriers prevent construction from responding, and rising demand manifests entirely as price increases.
NIMBYism: The political opposition of existing residents, typically homeowners, to new development near their properties. Derives its influence from homeowners' financial stake in scarcity and their disproportionate participation in local political processes.
Filtering: The process by which housing stock built for upper-income households gradually becomes accessible to lower-income households as it ages. Filtering requires a large and growing housing stock; when supply is constrained, filtering slows and lower-income households face unrelenting competition for existing units.
Inclusionary zoning: Requirements that a percentage of units in new residential developments be priced below market rate. Intended to produce affordable units but criticized for reducing overall housing production by raising development costs.
The Supply-Restriction Mechanism
The core economic argument about housing affordability is well-established and crosses political lines. Edward Glaeser and Joseph Gyourko published foundational research in 2003 comparing housing prices to construction costs across American cities. In markets without binding regulatory constraints, housing prices should approximately equal construction costs plus a reasonable profit: if they diverged significantly upward, developers would build until prices fell back toward costs. In highly constrained markets like San Francisco, New York, and Boston, however, Glaeser and Gyourko found prices far exceeding construction costs by margins they called the "zoning tax" — the premium attributable not to physical costs of building but to regulatory restrictions on what can be built.
Their estimate of the zoning tax in Manhattan exceeded $300,000 per unit in 2003 dollars. In San Francisco, the gap between construction cost and market price similarly reflected a regulatory premium many times the physical cost of building. This is not land cost per se — urban land can be priced into construction costs and the calculations control for land — but the restriction on how intensively land can be used. A single-family home on a lot that could legally support a six-story apartment building has a market price that reflects the lost value of the prohibited development.
Chang-Tai Hsieh and Enrico Moretti took this analysis further in their 2019 study in the American Economic Journal: Macroeconomics. They estimated the productivity losses from workers being unable to relocate to high-productivity cities because of housing cost barriers. Their headline finding — that land use restrictions in a handful of highly productive American metros had cost the US economy approximately two trillion dollars in GDP over a twenty-year period — reflects the aggregate effect of spatial misallocation: workers stuck in Detroit earning less than they would in San Francisco, because San Francisco cannot be afforded. This is not a second-order effect; it is among the largest sources of productivity loss in the American economy according to their calculations.
How Zoning Restricts Supply
American zoning law traces to Euclid v. Ambler Realty (1926), in which the Supreme Court upheld comprehensive zoning as a legitimate exercise of local government police power. The primary purpose of early zoning was separating industrial uses from residential neighborhoods. What developed over the subsequent decades was a system of land use regulation that went far beyond industrial separation and became a mechanism for restricting density and, critics argue, for excluding lower-income and non-white populations from desirable areas.
Richard Rothstein's "The Color of Law" (2017) documented extensively how zoning was explicitly used to enforce residential racial segregation, and how the wealth-building effects of homeownership in desirable areas were systematically denied to Black Americans through exclusionary land use policy. This history is inseparable from contemporary affordability debates: the neighborhoods that are most resistant to new housing today are often those whose exclusivity was originally enforced by overtly discriminatory means.
The specific mechanisms of supply restriction include several related regulations. Single-family zoning covering 70-80% of residential land in most large American cities means that even as prices rise dramatically, the most economically efficient response — adding density near existing infrastructure — is legally prohibited. Minimum lot size requirements prevent subdivision of existing lots for additional housing. Height limits prevent multistory construction. Setback and parking minimum requirements consume land that would otherwise accommodate housing. Floor-area ratio limits constrain how large a building can be relative to its lot. Environmental review requirements — which in California under CEQA (the California Environmental Quality Act) allow neighbors to challenge virtually any development project — add years of legal uncertainty and cost to housing production.
Each regulation individually may have a plausible purpose. The cumulative effect is to make legal housing construction in most desirable American neighborhoods either impossible or so expensive that only luxury projects pencil out economically. This is the mechanism behind a result that confuses many observers: housing production in expensive cities produces primarily luxury units, which seems to worsen affordability. The actual reason is that below-market construction is prohibited, not that developers prefer luxury — they build what the regulations make profitable at the margins of what is permitted.
The Political Economy of Restriction: Homevoters
Why do these restrictions persist given their well-documented costs? William Fischel, an economist at Dartmouth, developed the "homevoter" hypothesis to explain local land use politics. Homeowners, Fischel argues, are uniquely motivated political participants in local government because their most valuable asset — their home — is illiquid, undiversified, and vulnerable to changes in neighborhood characteristics. Unlike shareholders who can sell stock instantly, homeowners who decide their neighborhood is declining face large transaction costs in exiting. This illiquidity makes them intensely interested in local political decisions that affect neighborhood desirability.
Zoning restrictions that limit new housing supply have two effects that homeowners value: they preserve neighborhood character (loosely defined, but including density, traffic, parking, and aesthetic concerns), and they maintain or increase home values by constraining supply. A homeowner whose home is worth $600,000 in a constrained market might fear that liberalized zoning would allow a large apartment building next door, increasing traffic and reducing their property's "exclusivity premium." Whether or not these fears are empirically warranted — research on property value effects of nearby multifamily housing is mixed — they are politically potent.
Homeowners vote at high rates in local elections, participate in planning commission hearings, organize neighborhood associations, and have legal standing to challenge development approvals. Potential residents of new housing who do not yet live in the jurisdiction have none of these political resources. The result is a systematic political bias: local land use processes weight the interests of existing property owners heavily and the interests of future residents not at all. Vicki Been and colleagues at NYU Furman Center have studied this dynamic extensively, finding that planning bodies with high homeowner representation consistently approve less housing than those with more mixed membership.
The YIMBY Movement and Legislative Responses
The "Yes In My Back Yard" movement emerged in the mid-2010s in response to the failure of traditional affordable housing advocacy to address the supply constraint problem. Earlier affordable housing politics had focused on tenant protection (rent control), subsidized construction (public housing, low-income housing tax credits), and inclusionary zoning requirements — demand-side and targeted supply approaches that did not challenge the fundamental restriction on market-rate supply.
YIMBY groups, initially organized online in San Francisco and spreading rapidly to other expensive cities, argued that the primary cause of housing unaffordability was supply restriction and that the primary solution was allowing more market-rate construction. This position proved divisive. Some affordable housing advocates argued that market-rate construction did not help low-income residents. YIMBY economists responded that filtering — the process by which new market-rate units gradually become accessible to lower-income residents as they age — required a large and growing housing stock, and that restricting supply harmed low-income renters by eliminating the filtering mechanism.
The YIMBY movement has achieved legislative results. Oregon in 2019 became the first US state to eliminate single-family zoning statewide, allowing duplexes on any residential lot and larger multifamily buildings near transit. Minneapolis had eliminated single-family zoning in 2018. California passed a series of state preemption laws beginning in 2019, including SB 9 (allowing duplexes on single-family lots statewide) and SB 10 (streamlining multifamily approvals near transit). Reforms to CEQA have been attempted repeatedly, with limited success against organized opposition from environmental groups and NIMBY coalitions that use environmental review as a tool to delay and challenge housing projects.
Tokyo: The Natural Experiment
The most frequently cited comparison case for supply-liberal housing policy is Tokyo. Japan's national zoning framework allocates land use nationally rather than locally, using a system of 12 use categories ranging from exclusive residential to heavy industrial. Crucially, the framework prevents local governments from imposing restrictive exclusionary zoning beyond what national rules allow, and it permits relatively dense construction across much of the metropolitan area.
The result is striking. The Tokyo metropolitan area — home to approximately 37 million people, one of the largest urban agglomerations in human history — has maintained relatively flat real housing prices over the past 30 years, while comparable cities in the US, UK, and Australia have seen prices multiply several times. New housing starts in Tokyo regularly exceed those of the entire state of California. Construction is abundant, diverse in type and price point, and includes high-density multifamily buildings in areas that would be single-family zones in American suburbs.
Alain Bertaud (NYU Marron Institute) and other urban economists have studied Tokyo extensively as evidence that supply elasticity can maintain affordability even in very large, high-demand cities. The comparison is not perfect — Japan's population has been declining nationally while American cities face net growth, and Tokyo's success reflects decades of cultural and institutional development that cannot be easily replicated. But the Tokyo example serves as a powerful counter to the frequently asserted claim that housing simply cannot be built fast enough or cheaply enough in world cities to moderate prices.
Financialization: A Contested Explanation
A competing explanation for high housing costs, popular in left-leaning media and politics, focuses on the financialization of housing — the increasing treatment of residential real estate as an investment asset by institutional investors, private equity firms, and foreign buyers. The acquisition of large portfolios of single-family rental homes by companies like Invitation Homes (backed by Blackstone) became a significant political controversy in the early 2020s, as did the growth of platforms like Airbnb removing units from long-term rental markets.
The empirical evidence on financialization as a housing cost driver is more limited than its political salience suggests. Institutional investors own a small percentage of the total US housing stock — approximately 2-3% of single-family homes as of 2022 — though their concentration in specific markets (Atlanta, Phoenix, Charlotte) is higher. Academic research has found modest effects of institutional landlord entry on local rents. Airbnb's effects on housing markets have been studied extensively; Barron, Kung, and Proserpio (2021) found that a 1% increase in Airbnb listings was associated with a 0.018% increase in rents and 0.026% increase in house prices — real but small effects compared to the overall magnitude of unaffordability.
Foreign investment effects on housing prices have been a particular focus of political controversy in cities including Vancouver, Sydney, and London. Research on this question is methodologically challenging because foreign ownership is difficult to track. Studies examining Vancouver's foreign buyer tax (introduced 2016) found measurable price effects in the near term, with prices falling after the tax's introduction. But most economists who have examined housing prices in these cities attribute the majority of unaffordability to supply restriction rather than foreign investment, with the latter a contributing but secondary factor.
The strongest counter-argument to finance-focused explanations is comparative: the cities that have successfully maintained housing affordability — Tokyo, among Western cities Houston and Minneapolis — are not notable for limiting financialization or foreign investment. They are notable for allowing supply to respond to demand.
The Evidence on Affordable Housing Programs
If market-rate supply liberalization is the primary solution, what role should affordable housing programs play? The evidence on specific program types varies.
Housing vouchers (in the US, the Housing Choice Voucher program, formerly Section 8) provide direct rental assistance to low-income households, allowing them to rent in the private market. Research consistently finds that vouchers effectively help recipients — they reduce homelessness, improve housing quality, and in some studies improve educational outcomes for children. But vouchers work by subsidizing demand in an inelastic supply market, meaning they can increase prices for non-recipients competing for the same units. Their effectiveness depends on supply conditions.
Public housing — government-owned and operated housing for low-income residents — has a mixed record. Vienna's model (roughly 60% of residents in government or cooperative housing) is widely cited as successful; American public housing has been more troubled, with concentrated poverty, underfunding, and physical deterioration creating problems that some researchers attribute to design choices and funding failures rather than inherent problems with the model.
Inclusionary zoning requirements — mandating that developers include a percentage of affordable units in market-rate projects — are politically popular because they extract affordable housing from developers at no direct public cost. The problem is that requirements above a modest threshold (typically 10-15% of units at modest income restrictions) make development economically unviable, reducing total housing supply. Several studies have found that cities with high inclusionary requirements produce less total housing than comparable cities with lower requirements, potentially worsening affordability on net.
Rent control is perhaps the most politically contested housing policy tool. Research by Rebecca Diamond, Tim McQuade, and Franklin Qian (2019) studying San Francisco's 1994 rent control expansion found it reduced rental housing supply by 15% — as landlords converted rent-controlled units to condominiums or took them off the rental market — while protecting existing tenants of controlled units. The net effect on affordability was negative: the reduction in supply increased rents for uncontrolled units by 5-7%.
The Generational Wealth Gap Through Housing
Rising housing prices have produced one of the most significant intergenerational wealth transfers in modern economic history. Homeowners who purchased in major cities before the price run-up of the 1990s and 2000s have accumulated enormous wealth — in many cases, more than the present value of a lifetime's professional earnings. Their adult children who cannot afford to buy homes in the same cities face a bifurcated economic future: those who inherit or receive parental help with down payments participate in housing wealth accumulation; those who do not rent indefinitely in markets where their rent flows to landlords who benefit from the same scarcity that excludes them from ownership.
This dynamic operates with particular force through geography and race. Black homeownership rates, historically suppressed by discriminatory policies documented by Rothstein and others, mean Black households have accumulated less housing wealth. Younger cohorts generally have lower homeownership rates than their parents at the same age, reflecting rising prices relative to income. Research by Matthew Rognlie (2015) found that the rising share of capital income relative to labor income that Thomas Piketty documented in "Capital in the Twenty-First Century" is largely explained by rising housing values — housing has been the dominant source of capital income growth.
Practical Implications
The research points toward a relatively clear policy agenda, though the political obstacles to implementing it are formidable. Supply liberalization — allowing more housing types in more places near jobs and transit — is the most robustly supported intervention. State-level preemption of exclusionary local zoning, as Oregon and California have attempted, addresses the homevoter problem by elevating housing decisions above the local political scale where NIMBY coalitions are most powerful.
For individuals, the housing crisis creates difficult trade-offs. Renting in expensive cities may be economically rational compared to buying at stretched valuations. Locating in cities with more elastic housing supply — historically including Dallas, Houston, Atlanta, and Phoenix among major US metros — involves lower housing costs but may mean lower wages in some fields. The case for homeownership as a wealth-building strategy depends heavily on local supply conditions: in constrained markets, it has been an extraordinary investment; in elastic markets, its financial advantages over renting are more modest.
See also: What Explains the Gender Pay Gap | How Poverty Traps Work | Why Social Comparison Makes Us Miserable
References
- Glaeser, E., & Gyourko, J. (2003). "The Impact of Zoning on Housing Affordability." NBER Working Paper 8835.
- Hsieh, C.T., & Moretti, E. (2019). "Housing Constraints and Spatial Misallocation." American Economic Journal: Macroeconomics, 11(2), 1-39.
- Fischel, W. (2001). The Homevoter Hypothesis. Harvard University Press.
- Shiller, R. (2005). Irrational Exuberance (2nd ed.). Princeton University Press.
- Rothstein, R. (2017). The Color of Law: A Forgotten History of How Our Government Segregated America. Liveright.
- Bertaud, A. (2018). Order Without Design: How Markets Shape Cities. MIT Press.
- Diamond, R., McQuade, T., & Qian, F. (2019). "The Effects of Rent Control Expansion on Tenants, Landlords, and Inequality." American Economic Review, 109(9), 3365-3394.
- Mast, E. (2021). "The Effect of New Market-Rate Housing Construction on the Low-Income Housing Market." Upjohn Institute Working Paper 19-307.
- Barron, K., Kung, E., & Proserpio, D. (2021). "The Effect of Home-Sharing on House Prices and Rents: Evidence from Airbnb." Marketing Science, 40(1), 23-47.
- Rognlie, M. (2015). "Deciphering the Fall and Rise in the Net Capital Share." Brookings Papers on Economic Activity, 1-69.
- Chetty, R., Hendren, N., & Katz, L. (2016). "The Effects of Exposure to Better Neighborhoods on Children." American Economic Review, 106(4), 855-902.
- Been, V., Madar, J., & McDonnell, S. (2014). "Urban Land Use Regulation: Are the Costs Worth the Benefits?" Fordham Urban Law Journal, 42(1), 103-154.
Frequently Asked Questions
Why has housing become so unaffordable in most cities?
The primary driver, according to the preponderance of economic research, is a severe constraint on housing supply in the most economically productive cities. Land use regulations — zoning restrictions, height limits, minimum lot size requirements, parking mandates, setback rules, and lengthy permitting processes — have dramatically limited new housing construction in high-demand areas. When population and economic activity grow but housing supply cannot respond, prices rise. This is a basic supply and demand dynamic that economists across the political spectrum largely agree on, even as they disagree on secondary factors. Contributing factors include: increased construction costs from both labor and materials; financialization of housing that treats it as an investment asset; and, in some specific markets, foreign investment and short-term rental platforms that remove units from the long-term rental market. But empirical research consistently identifies supply constraint as the dominant mechanism.
What does economic research say is the main cause of high housing costs?
Edward Glaeser (Harvard) and Joseph Gyourko (Wharton) published landmark research in 2003 finding that housing prices in constrained markets exceed construction costs by margins that cannot be explained by land costs alone — the excess price represents a regulatory 'zoning tax.' In San Francisco, they estimated the gap between construction costs and market prices reflected a regulatory tax equivalent to several hundred thousand dollars per unit. Chang-Tai Hsieh (University of Chicago) and Enrico Moretti (UC Berkeley) published research in 2019 finding that land use restrictions in high-productivity cities like New York, San Francisco, and San Jose had reduced aggregate US GDP by approximately two trillion dollars over two decades, by preventing workers from relocating to where they would be most productive. The Economist, IMF, and OECD have all published analyses reaching similar conclusions: supply restriction is the dominant causal factor in housing unaffordability in wealthy countries.
Does building more housing actually lower prices?
Yes, though the relationship is sometimes more complex than a simple linear model suggests. The most rigorous evidence comes from natural experiments and studies of housing construction across cities. Research by Evan Mast (2021) and others found that building market-rate housing — even luxury apartments — reduces rents in nearby buildings as residents 'filter' through the housing stock: new luxury residents move out of previously occupied units, reducing pressure on the rental market. The Tokyo metropolitan area is the most-cited natural experiment: Japan's national zoning framework allows relatively liberal construction across Tokyo, and despite being one of the world's largest cities, Tokyo's real housing prices have remained essentially flat over 30 years while comparable cities in the US, UK, and Australia have seen prices multiply. The mechanism is straightforward: when supply is elastic, demand increases translate into more housing units rather than higher prices.
How does zoning cause housing to be expensive?
Zoning regulations determine what can be built where. Large-lot single-family zoning — which prevents apartment buildings or even duplexes in designated areas — is the most significant mechanism. In most large American cities, 70-80% of residential land is zoned exclusively for single-family homes, preventing the densification that would allow more housing near jobs. Height limits constrain how many units can be built on available land. Parking minimums — requirements that each unit include one or two off-street parking spaces — consume land and add significant construction cost. Environmental review processes and neighbor appeal rights extend permitting timelines from months to years. Impact fees add tens of thousands of dollars per unit. The cumulative effect of these restrictions is that housing in high-demand areas cannot be supplied at or near construction cost, because restrictions either prohibit construction outright or add costs that make it economically unviable except at premium price points.
What is NIMBYism and how does it affect housing supply?
NIMBY ('Not In My Back Yard') describes the political opposition of existing residents and homeowners to new housing development near their homes. Homeowners have strong financial incentives to oppose new supply: their home is typically their largest asset, and they benefit from price appreciation caused by scarcity. They also vote at high rates in local elections — which determine zoning decisions — and have organizational advantages over potential future residents who do not yet live in the area and cannot vote in its elections. The result is a systematic political bias toward restricting supply. Research by William Fischel at Dartmouth describes homeowners as 'homevoters' — a politically dominant constituency in suburban jurisdictions whose incentives consistently push toward supply restriction. Vicki Been and colleagues at NYU have studied local land use political economy and found that owner-occupier dominated planning bodies approve far less housing than renter-dominated ones. The YIMBY (Yes In My Back Yard) movement emerged in the 2010s as an organized counter-coalition, with some legislative success in states including California, Oregon, and Minnesota.
What policies have successfully made housing more affordable?
The strongest evidence is for supply liberalization. Japan's national zoning framework that preempts restrictive local rules helps explain Tokyo's stable prices. Minneapolis eliminated single-family zoning citywide in 2018 and has seen relative affordability compared to comparable Midwestern cities. Oregon legalized duplexes statewide in 2019. California has passed multiple state preemption laws limiting local governments' ability to block certain housing types. The evidence on demand-side subsidies (housing vouchers, public housing) is that they help individual recipients but do not reduce prices market-wide when supply is inelastic. Inclusionary zoning — requiring a percentage of units in new developments to be affordable — can reduce affordability among the units included but reduces total supply if requirements are set too high, potentially worsening overall affordability. Public construction programs (Vienna, Singapore) can work at scale but require sustained political commitment and fiscal capacity. No single policy has worked in all contexts; the most consistent finding is that increasing supply is necessary.
Is buying a house still a good investment?
Robert Shiller, the Yale economist who co-won the Nobel Prize in Economics in 2013 and whose Case-Shiller home price index is the standard measure of US housing prices, has argued that residential real estate is a mediocre investment over long historical periods. His research found that US home prices rose only about 0.4% annually in real (inflation-adjusted) terms between 1890 and the early 2000s. The dramatic price appreciation since the late 1990s — and the 2008 crash — represented departures from this long-run trend. Owning a home provides consumption value (shelter), leverage, tax advantages, and inflation hedging, which make it rational as a household financial strategy in many contexts. But the investment returns on housing have been substantially lower than returns on equities over comparable periods. In cities with restrictive zoning, home prices have appreciated rapidly — meaning early buyers benefited enormously from scarcity rents — but this represents wealth transfer from renters and later buyers rather than economic value creation.