Median multiple
The median multiple is a housing affordability indicator calculated by dividing the median house price by the gross annual median household income in a given metropolitan market.[1] This price-to-income ratio, employing medians to mitigate the influence of outliers, offers a straightforward, comparable assessment of how many years of typical household earnings are required to purchase a typical home.[2] Markets are classified by Demographia as affordable at 3.0 or below, moderately unaffordable between 3.1 and 4.0, seriously unaffordable from 4.1 to 5.0, and severely unaffordable above 5.1, with the latter category dominating in many major cities due to supply constraints from regulatory barriers rather than demand-side factors alone.[3] Popularized through annual Demographia International Housing Affordability surveys starting in the mid-2000s, the metric underscores empirical patterns where freer land-use policies correlate with lower multiples, challenging narratives that attribute unaffordability primarily to income disparities or speculation.[1][4]Definition and Calculation
Formula and Components
The median multiple is a price-to-income ratio defined as the median house price divided by the gross median household income, serving as a core metric for evaluating housing affordability in metropolitan markets.[2] This calculation employs medians rather than means to mitigate the influence of outlier values, such as luxury properties or exceptionally high earners, thereby better approximating conditions for middle-income households.[5] The formula is expressed as: \text{Median Multiple} = \frac{\text{Median House Price}}{\text{Median Household Income}} The median house price component captures the central value among prices of homes sold within a specified metropolitan housing market, typically prioritizing established single-family houses or equivalent dwelling types that constitute the majority of owner-occupied housing stock.[2] Data for this are derived from authoritative sources including official government sales transaction registers (such as those in Ireland, England, and Wales), real estate industry time-series databases, or market analytics reports, ensuring representation of actual transaction prices rather than asking prices or new constructions.[5] This focus on median transaction prices standardizes comparisons across markets while excluding atypical segments like high-end condominiums unless they dominate local supply. The median household income component refers to the pre-tax gross annual income at the 50th percentile for all households in the relevant metropolitan area or national context, reflecting typical earning power before deductions.[2] Incomes are estimated using contemporaneous official government statistics, such as census-based surveys or labor market data from statistical agencies, to align with the timing of house price observations and avoid temporal mismatches.[5] Gross rather than net income is used to maintain simplicity and comparability, as tax regimes and deductions vary widely across jurisdictions. Together, these components yield a dimensionless ratio that facilitates objective, apples-to-apples assessments of affordability trends over time or between markets, though it abstracts from factors like mortgage interest rates, property taxes, or maintenance costs.[2] Demographia applies this formula consistently to third-quarter data from major urban markets, updating annually to track shifts driven by supply constraints, income growth, or policy changes.[5]Interpretation as an Affordability Metric
The median multiple functions as a core affordability metric by quantifying the relationship between the cost of acquiring a typical home and the earning capacity of a typical household, thereby highlighting the financial accessibility of homeownership for middle-income earners. Specifically, it divides the median dwelling price by the gross annual median household income, yielding a ratio that, when low, implies households can allocate a smaller proportion of income to housing without undue strain, assuming standard financing terms. This approach draws from economic principles where housing costs exceeding three times annual income historically signaled overextension, a threshold validated in pre-2000 data across developed economies where multiples rarely surpassed 3.0.[5][2] Demographia applies standardized thresholds to interpret the metric's implications for market health:| Median Multiple | Affordability Rating |
|---|---|
| 3.0 or less | Affordable |
| 3.1–4.0 | Moderately unaffordable |
| 4.1–5.0 | Seriously unaffordable |
| 5.1 or greater | Severely unaffordable |
Historical Development
Origins in Economic Analysis
The house price-to-income ratio emerged as a key metric in economic analysis during the 1970s, amid observations of diverging housing costs and household earnings in advanced economies. Early discussions highlighted how rapid house price inflation outpaced real income growth, with U.S. median home prices nearly doubling from 1970 to 1977 while family incomes rose more modestly, signaling emerging affordability pressures.[10] This ratio provided a straightforward empirical tool to evaluate whether housing markets aligned with fundamental demand drivers like income, contrasting with more complex models reliant on interest rates or rents.[11] By the early 1980s, economists formalized its use in assessing market dynamics and policy impacts. Studies examined the ratio to decompose house price movements into components influenced by income, credit availability, and fiscal incentives, such as tax deductions that effectively subsidized homeownership for higher earners.[12] For instance, research on owner-occupied housing modeled how inflation interacted with income taxes to alter the relative attractiveness of housing as an asset, predicting shifts in the price-to-income equilibrium based on expected real returns.[13] These analyses treated the ratio as a benchmark for long-term sustainability, assuming stable fundamentals would keep it within historical norms of 3 to 5 times annual income, deviations from which could indicate bubbles or structural imbalances.[14] Urban and macroeconomists in the late 1980s extended the metric to cross-sectional comparisons across cities, linking regional price-income disparities to factors like local tax policies and migration patterns.[15] This empirical tradition underscored the ratio's value in testing hypotheses about housing as a durable good, where prices should track income growth over time absent supply constraints or speculative fervor. Such work established the intellectual foundation for affordability metrics, emphasizing causal links between income as a demand determinant and price sustainability, independent of short-term financing conditions.[16]Adoption by Demographia
Demographia, an independent public policy firm founded by Wendell Cox and Hugh Pavletich, adopted the median multiple as the primary metric for assessing housing affordability in its inaugural International Housing Affordability Survey published in 2005.[17] The survey evaluated 48 major urban markets across Australia, Canada, Ireland, New Zealand, the United Kingdom, and the United States, calculating the ratio using third-quarter 2004 data to reveal emerging affordability crises, with multiples exceeding 5.0 in markets like Sydney (7.9) and London (8.0).[18] This adoption emphasized the metric's advantages over alternatives like mean-based ratios, which are susceptible to skew from luxury housing outliers, ensuring a focus on middle-income households.[19] The decision to prioritize the median multiple stemmed from its established use in international economic analysis, including endorsements by the World Bank and United Nations for evaluating urban market affordability due to its simplicity, reproducibility, and historical benchmark of 3.0 or below in affordable pre-1990s markets.[20] Pavletich and Cox argued that the metric's consistency across jurisdictions facilitated direct comparisons, highlighting policy-driven factors like land-use restrictions that had driven multiples upward since the late 1990s, as evidenced by baseline data showing multiples below 4.0 in most surveyed areas prior to that period.[18] By standardizing on gross pre-tax median household income against median unqualified house prices, Demographia avoided adjustments for regional income variations or mortgage qualifications, prioritizing raw price-income disequilibria.[5] Since 2005, Demographia has issued annual editions expanding to over 90 markets by 2023, consistently applying the median multiple to categorize affordability from "affordable" (3.0 and under) to "impossibly unaffordable" (9.0 and over, introduced in later reports), influencing policy discussions on housing supply constraints.[7] The firm's methodology draws from official government statistics and real estate data sources, such as the UK's Nationwide Building Society and Australia's CoreLogic, to maintain verifiability, though critics note potential limitations in data harmonization across countries.[5] This sustained use has positioned the median multiple as a de facto standard in global housing discourse, underscoring empirical trends of deterioration in high-regulation markets.[3]Methodology and Data Sources
Measurement Standards
The median multiple is calculated as the ratio of the median house price to the gross median household income in a given metropolitan market.[5] This measure employs medians rather than means to mitigate distortion from outlier high prices or incomes, thereby better reflecting affordability for middle- and lower-income households.[2] Median house prices are derived from data on the majority of existing owned dwellings, prioritizing sales of established homes over new constructions to capture typical market conditions.[5] Sources include official government sales registers, such as those in Ireland, England, Wales, and Scotland, or authoritative real estate time series and market reports where government data is unavailable.[2] These prices represent actual transaction values in the third quarter of the assessment year, ensuring recency and alignment with contemporaneous income data.[5] Gross median household income is estimated using official government statistics for the same period, capturing pre-tax earnings across household units in the metropolitan area.[2] Metropolitan markets are delineated by labor market commuting zones to maintain consistency in comparing housing costs against incomes earned within the same economic catchment.[5] No adjustments for purchasing power parity or regional cost variations are applied, preserving the metric's simplicity as a raw structural indicator endorsed by organizations like the United Nations Human Settlements Programme and the World Bank for basic affordability assessments.[21]Challenges in Cross-Jurisdictional Comparisons
Cross-jurisdictional comparisons of the median multiple face challenges stemming from variations in housing stock characteristics. The metric relies on median house prices that may encompass dissimilar property types, such as detached single-family homes in suburban-oriented markets versus apartments or townhouses in denser urban areas, leading to inflated ratios in jurisdictions where single-family dwellings predominate but represent a smaller share of transactions. For instance, critics argue that Demographia's emphasis on single-family house prices overlooks lower-cost multifamily options prevalent in markets like Vancouver, potentially exaggerating unaffordability by up to double when weighted medians including apartments are considered.[5][22] Demographia acknowledges that the approach does not adjust for differences in house sizes, build quality, or amenities, which can vary systematically across countries—for example, larger homes in the United States compared to more compact units in parts of Europe or Asia—thus limiting direct equivalence.[23][5] Data collection and definitional inconsistencies further complicate comparability. House price medians are derived from national or local real estate transaction records, but sources differ: government registries in places like the United Kingdom provide comprehensive sales data, while estimates from real estate agents or indices are used elsewhere, introducing potential variances in coverage and timeliness.[5] Median household incomes, drawn from census or official surveys, may lag by one to two years relative to price data and employ slightly varying household composition criteria across jurisdictions, such as inclusion of dependents or earners. Moreover, the use of gross (pre-tax) incomes ignores divergent tax regimes and social benefits, where higher-tax nations like those in Scandinavia effectively subsidize housing through transfers, altering net affordability not captured by the raw ratio.[5][24] Regulatory and market structure differences exacerbate these issues. Mortgage availability, down payment requirements, and interest deductibility vary— for example, low down payments in Canada versus stricter lending in Europe—impacting the feasibility of purchases at given multiples, yet the metric treats them uniformly.[5] Local zoning and land-use policies influence supply responsiveness differently, with contained markets like Hong Kong showing distorted multiples due to geographic constraints not paralleled in expansive U.S. metros, rendering causal inferences across borders tentative.[22] While Demographia standardizes by focusing on metropolitan labor markets to enhance internal consistency within nations, international aggregation remains approximate, as evidenced by critiques highlighting non-transparent data weighting that may bias toward less affordable outcomes in supply-constrained contexts.[5][25] These limitations underscore that, although the median multiple enables broad trend identification, precise cross-jurisdictional rankings require supplementary adjustments for contextual factors to avoid misleading interpretations.Affordability Ratings and Categories
Rating Scale
Demographia International Housing Affordability surveys classify housing markets into five affordability categories based on the median multiple, a standardized price-to-income ratio derived from median house prices divided by gross annual median household income. These categories provide a benchmark for assessing middle-income housing accessibility, with lower multiples indicating greater affordability aligned with historical norms observed in market-oriented economies. The scale originates from economic analyses by organizations including the World Bank and United Nations, which have endorsed multiples of 3.0 or below as indicative of affordable conditions for typical households.[8][21] The ratings are as follows:| Category | Median Multiple Range |
|---|---|
| Affordable | 3.0 and under |
| Moderately Unaffordable | 3.1 to 4.0 |
| Seriously Unaffordable | 4.1 to 5.0 |
| Severely Unaffordable | 5.1 to 8.9 |
| Impossibly Unaffordable | 9.0 and over |
Global Market Assessments
The Demographia International Housing Affordability 2025 Edition evaluated median multiples in 95 major metropolitan markets across eight nations—Australia, Canada, China, Ireland, New Zealand, Singapore, the United Kingdom, and the United States—covering data through the third quarter of 2024.[3] For the first time in the survey's history, no market achieved an "affordable" rating, defined as a median multiple of 3.0 or below, signaling a widespread erosion of housing affordability for middle-income households in these locations.[6] Markets were categorized as moderately unaffordable (3.1–4.0), seriously unaffordable (4.1–5.0), severely unaffordable (5.1–9.0), or impossibly unaffordable (above 9.0), with the majority falling into the severely or impossibly unaffordable brackets.[3] Hong Kong recorded the highest median multiple at 14.4, rendering it impossibly unaffordable and the least accessible major market globally in the assessment.[26] Sydney followed closely with a median multiple of 13.8, also impossibly unaffordable and ranking as the second-worst market.[2] Other notably unaffordable markets included Honolulu at 10.8 and several Canadian cities like Vancouver, which have persistently high ratios exceeding 10.0 in prior editions, though exact 2025 figures for all underscore a pattern of extreme price-income disparities driven by limited supply responsiveness.[2] In contrast, even relatively better-performing markets in the United States, such as those in the Midwest, exceeded the 3.0 threshold, with no U.S. major market qualifying as affordable.[6]| Category | Median Multiple Range | Examples from 2025 Assessment |
|---|---|---|
| Affordable | ≤3.0 | None |
| Moderately Unaffordable | 3.1–4.0 | Limited; some peripheral U.S. and Australian markets approached but did not meet |
| Seriously Unaffordable | 4.1–5.0 | Various mid-tier North American and European markets |
| Severely Unaffordable | 5.1–9.0 | Majority, including Los Angeles (9.6 in recent data) |
| Impossibly Unaffordable | >9.0 | Hong Kong (14.4), Sydney (13.8), Honolulu (10.8) |
Empirical Trends and Findings
Pre-2000 Baselines
Prior to 2000, median multiples in major housing markets across the United States, Canada, Australia, the United Kingdom, Ireland, and New Zealand typically ranged from 2.0 to 3.0, reflecting broadly affordable conditions for middle-income households.[28][5] This benchmark, derived from historical price and income data, indicated that median house prices required no more than three years of gross median household income, enabling homeownership without disproportionate debt burdens.[18] Demographia reports note that multiples exceeding 3.0 were exceptional before the 1990s, with the norm aligning closely across these nations due to relatively unconstrained land supply and construction markets.[29] In the United States, national data from 1960 to 2000 show an average price-to-income ratio of approximately 2.6, supporting consistent affordability amid rising incomes and steady price growth.[30] For example, in 1985, the median home price stood at $82,800 against a median household income of $23,620, yielding a ratio of about 3.5—still within reachable bounds for many markets, though higher than the long-term average.[31] By 2000, two-thirds of large U.S. metropolitan areas maintained ratios below 3.0, underscoring the pre-millennium baseline of accessibility.[32] These pre-2000 figures contrast with later escalations, as urban containment policies and regulatory expansions began restricting supply in select regions from the late 1980s onward, though widespread deterioration occurred post-2000.[1] Historical analyses emphasize that such low multiples facilitated economic mobility, with homeownership rates peaking in the U.S. at around 69% by 2004, built on decades of stable ratios.[33]Post-2000 Deterioration and Recent Data
Since the early 2000s, housing affordability as measured by the median multiple has deteriorated markedly across major international markets, with median house prices outpacing median household income growth. In the United States, the national median multiple rose from around 3.0 in the 1990s to 4.0 by 2019 and reached 4.8 in 2023, reflecting an additional nearly one year of income required to purchase a median home compared to pre-pandemic levels.[5] This trend accelerated post-2005, coinciding with tightened land-use regulations in many urban areas, though income growth stagnation and credit expansion also contributed.[3] Australia exemplifies severe post-2000 decline, with the national median multiple climbing to 8.0 by 2022 from approximately 4.0-5.0 in the early 2000s, driven by stringent supply restrictions in coastal cities like Sydney and Melbourne.[34] Canada's major markets, such as Vancouver and Toronto, saw multiples exceed 10.0 by the mid-2010s, up from under 5.0 pre-2000, amid similar regulatory barriers to development.[5] In Europe, London’s median multiple increased to 8.3 by the late 2010s, contrasting with more stable affordability in less regulated Eastern European cities.[29] Recent data from the 2025 Demographia International Housing Affordability report, based on third-quarter 2024 figures, underscore ongoing exacerbation, with no surveyed market rated "affordable" (median multiple ≤3.0). Hong Kong remained the least affordable at 14.4, followed by Sydney at 9.6 and San Francisco at 9.5, while even relatively affordable U.S. markets like Pittsburgh hovered at 3.1.[2][3] Globally, the 25 least affordable markets all exceeded 5.0, with 94 major markets averaging 5.3 in 2024, up from historical norms under 4.0. This persistent upward trajectory highlights supply constraints outweighing demand moderators like higher interest rates in recent years.[2]Criticisms and Limitations
Methodological Critiques
Critics argue that the median multiple, as a price-to-income ratio, oversimplifies housing affordability by relying on a single static metric that disregards dynamic factors such as prevailing mortgage interest rates, which directly influence monthly payments and borrowing capacity.[35] This omission can mislead assessments, as lower rates may offset higher prices without altering the ratio, while rising rates exacerbate burdens irrespective of nominal price-income levels.[35] Similarly, the measure excludes ancillary homeownership costs including property taxes, insurance, maintenance, and utilities, which collectively can represent 20-30% of total housing expenses in many markets.[36] The use of aggregate medians introduces further distortions, as the median house price reflects sales across varying property qualities and locations, without adjustments for structural differences or desirability, potentially equating a premium urban dwelling with a suburban equivalent.[37] Buyer demographics compound this issue: actual home purchasers often earn above the overall median household income, skewing the ratio's relevance for marginal buyers while masking affordability for higher earners.[36] In Demographia's implementation, the focus on single-family detached houses—excluding condominiums, townhouses, and apartments—biases results toward inaffordability in land-constrained, denser markets where multi-unit options predominate and command lower price multiples.[25] For instance, Vancouver's reported median multiple of 10.6 drops to approximately 5.4 when incorporating apartment sales data.[22] Cross-jurisdictional applications amplify methodological vulnerabilities through inconsistent data definitions and sources; national statistics may vary in timing, inclusion criteria (e.g., new vs. existing sales), and income metrics (gross versus disposable), undermining comparability without standardization.[37] Demographia's surveys have faced scrutiny for opaque sourcing and occasional factual discrepancies, such as overstated median prices in specific cities like Vancouver (reported at US$704,800 versus verified [CA](/page/CA)638,500 equivalent in December 2014 data), limiting peer verification.[22] These critiques, often from urban planning scholars advocating density-oriented policies, highlight the ratio's potential to overemphasize price signals at the expense of broader consumption-adjusted or residual income approaches that better capture heterogeneous household preferences and total location costs.[25][37]Responses to Supply-Side Explanations
Critics of supply-side explanations for elevated median multiples contend that local regulatory constraints, such as zoning and land-use restrictions, fail to account for the uniform deterioration in housing affordability observed across diverse markets. A 2024 NBER working paper by Rhoulani, Giglio, and Van Nieuwerburgh examines U.S. metropolitan areas from 1980 to 2020, finding that real house price growth and housing quantity growth exhibit similar patterns regardless of local supply elasticity, as measured by geographic and regulatory factors.[38] The authors employ a structural demand-and-supply model, demonstrating that if inelastic supply were the dominant driver, price increases would disproportionately affect constrained cities relative to elastic ones like Houston or Atlanta; however, empirical data reveal comparable price-to-income escalations nationwide, implying supply constraints explain only a minor fraction of aggregate price rises.[38][39] Proponents of this view attribute much of the post-2000 surge in median multiples—often exceeding 5.0 in major markets—to nationwide demand pressures, including prolonged low interest rates set by central banks. Federal Reserve policies from 2008 to 2021, which reduced 30-year mortgage rates to historic lows below 3% in 2020-2021, expanded borrowing capacity by approximately 50% for median-income households, fueling bidding wars and price inflation independent of local supply conditions. This effect compounded in all markets, as lower rates shifted the effective demand curve upward uniformly, with elastic supply areas absorbing some quantity growth but still registering median multiple increases from around 3.0 pre-2000 to 4.5 or higher by 2022.[40] Empirical simulations in the NBER analysis confirm that demand-side income and financing shocks better replicate observed price-quantity dynamics than supply-side variations alone.[38] Additional responses highlight migration and investor demand as amplifying factors overlooked by supply-centric models. Interstate migration to high-amenity but supply-constrained regions, such as from 2010-2020 when over 5 million net migrants entered Sun Belt metros, drove localized demand spikes that outpaced even moderate supply responses, yet similar multiple deteriorations appeared in low-regulation donor regions like the Midwest. Institutional investors, acquiring 15-20% of single-family homes in select markets by 2021, further distorted prices through cash purchases, effects not mitigated by supply elasticity since investment flows followed national capital availability rather than local building permissiveness. These demand dynamics, critics argue, underscore causal realism in prioritizing macroeconomic levers over localized deregulation, though supply-side advocates counter that elastic markets like Dallas maintained sub-4.0 multiples longer due to fewer barriers.[40] Overall, such responses posit that while supply constraints exacerbate local shortages, they do not causally dominate the secular rise in median multiples, which aligns more closely with synchronized national demand expansions.Alternatives and Complementary Measures
Price-to-Rent Ratios
The price-to-rent ratio measures the affordability of purchasing a home relative to renting a comparable property, calculated as the median home price divided by the annual gross rent for a similar unit.[41] This metric indicates the number of years of rent required to recoup the purchase price, assuming no other costs; ratios below 15 typically favor buying over renting due to lower relative ownership costs, while ratios above 20 suggest renting is more economical.[42] Unlike the median multiple, which assesses buyer affordability against household incomes, the price-to-rent ratio focuses on the opportunity cost of capital tied up in ownership versus rental yields, making it a key indicator for investors and for detecting deviations from rental fundamentals in housing markets.[43] Empirically, U.S. national price-to-rent ratios have trended upward since the 1970s, averaging 102.46 index points from 1970 to 2024, with a peak of 140.30 in Q2 2022 amid low interest rates and post-pandemic demand surges.[44] In major cities, ratios vary significantly: as of 2024, Cleveland exhibited a low ratio of 11.0, indicating buying advantages, while San Francisco's ratio exceeded 30, signaling rental preference and potential overvaluation relative to rents.[45] Studies attribute much of the post-2000 rise in ratios to factors like declining mortgage rates and relaxed lending, which accounted for over half of the U.S. house price-rent increase from 1995 to 2006, though supply constraints amplified effects in inelastic markets.[46] As a complement to price-to-income ratios, the price-to-rent metric isolates housing valuation from income growth, revealing bubbles where prices outpace rents despite stagnant earnings; for instance, the U.S. experienced elevated price-to-rent but moderated price-to-income exuberance pre-2008, contributing to rental inflation pressures.[47] However, its limitations include sensitivity to rent controls or investor distortions, which can suppress observed rents below market values, and an assumption of equilibrium yields that ignores transaction costs or tax incentives favoring ownership.[48] In supply-constrained areas, both ratios rise, but price-to-rent better captures investor-driven dynamics where elastic supply mitigates price impacts more than rent impacts.[49]| City (2024) | Price-to-Rent Ratio |
|---|---|
| Cleveland, OH | 11.0[45] |
| Pittsburgh, PA | 11.9[45] |
| Chicago, IL | 12.1[45] |
| San Francisco, CA | >30[45] |