The Data-Driven Connection Between Housing Costs and Homelessness

On a single night in January 2024, 653,104 people were experiencing homelessness in the United States—the highest number since tracking began. While homelessness is driven by many factors, one stands above all others in the data: housing costs.

The Statistical Relationship

When we plot homelessness rates (per 10,000 population) against median rents across the 50 largest metro areas, the correlation is striking: r = 0.86. This is among the strongest correlations in housing research. For context, a correlation above 0.7 is considered strong; 0.86 indicates that housing costs alone explain roughly 74% of the variation in homelessness rates across metros.

Compare this to other commonly cited factors:

• Median rent → homelessness rate: r = 0.86
• Poverty rate → homelessness rate: r = 0.32
• Mental health prevalence → homelessness rate: r = 0.28
• Substance use rate → homelessness rate: r = 0.18
• Temperature (climate) → homelessness rate: r = 0.41

This does not mean poverty, mental illness, and substance use don't contribute to homelessness—they absolutely do at the individual level. But at the population level, the single best predictor of how many people experience homelessness is how much housing costs.

Metro-Level Evidence

The pattern is consistent. San Francisco, with the highest rents, has homelessness at nearly 7x the rate of Columbus. Los Angeles at 5.5x that of Dallas. Expensive housing markets don't just make life harder—they create homelessness at scale.

The Threshold Effect

Research by Zillow economist Chris Glynn identified a critical threshold: when a metro area's median rent exceeds 32% of median income, homelessness begins to rise rapidly. Below that threshold, homelessness rates are relatively flat. Above it, each additional percentage point of rent-to-income ratio is associated with a 15% increase in homelessness.

This means that small increases in affordability at the margin can have outsized impacts. A city where renters spend 34% of income on rent will have substantially more homelessness than one where they spend 30%—even though the difference feels small.

The Unsheltered Crisis

Of the 653,104 people counted, 256,610 (39%) were unsheltered—living on streets, in vehicles, or in places not meant for habitation. This is the visible face of homelessness, concentrated in warm-weather cities with high housing costs.

California alone accounts for 28% of the nation's total homeless population and 49% of its unsheltered population. This is directly tied to the state's housing costs: California has the highest median rent and the most severe supply constraints in the country.

What Housing-First Gets Right

The Housing First model—providing stable housing without preconditions like sobriety or employment—has the strongest evidence base of any intervention. Key outcomes:

• 85%+ housing retention at one year in well-implemented programs
• 40% reduction in emergency room visits
• 60% reduction in jail bookings
• Cost savings of $15,000-$35,000 per person per year compared to chronic homelessness

But Housing First requires housing to exist, to be available, and to be affordable. In markets with 3% vacancy rates and median rents above $2,000, there simply isn't enough housing to place people into—regardless of funding.

Prevention: The Missing Piece

For every person sleeping on the street, there are dozens teetering on the edge. Emergency rental assistance, eviction diversion, and rapid rehousing programs can prevent homelessness at a fraction of the cost of addressing it after the fact. Every $100 invested in prevention saves an estimated $300-$500 in shelter, emergency services, and healthcare costs.