The Impact of Permanent Supportive Housing on Homeless Populations

Summary

"The Impact of Permanent Supportive Housing on Homeless Populations" is a 2017 paper by Kevin Corinth (then at the American Enterprise Institute), published in the Journal of Housing Economics 35: 69–84. It is carried on this wiki as a caveat-side source for Outcome: Homelessness is a housing-cost problem: it complicates the intervention corollary — that adding housing units to a community reduces its homeless population roughly one-for-one — while leaving the market-level rent-and-vacancy evidence of Quigley et al., Hanratty and Colburn & Aldern untouched.

Per the abstract: "Between 2007 and 2014 in the United States, national counts of the homeless population decreased as permanent supportive housing (PSH) for the homeless increased. Using a panel dataset from all communities across the country during this period, I investigate the effect of PSH on homeless population sizes."[1]

Core Findings

• The association is small. Controlling for time-invariant community factors and several time-varying ones, "one additional PSH bed is associated with between 0.04 and 0.12 fewer homeless people."[1] Far from a bed-for-a-person offset, most of a new PSH bed does not show up as a reduction in the counted homeless population.
• The causal (IV) estimate is also small — and imprecise. Using "federal funds allocated to communities for homeless assistance as instruments," Corinth finds that "adding one PSH bed reduces the homeless count by up to 0.10 people, and I can reject a reduction of more than 0.72 people at the 95% confidence level."[1] The point estimate is small; even the upper bound is less than a one-for-one reduction.
• In the companion working paper, the effect fades after year one. Corinth's AEI working paper "Ending Homelessness: More Housing or Fewer Shelters?" (2015) reports that "in the first year, one additional permanent housing bed is associated with 0.12 fewer homeless people on the streets and in shelters; however, this negative association is fully muted after the first year," with the muting "driven entirely by the homeless subpopulation with relatively shorter spells of homelessness."[2]

Why It Is a Caveat, Not a Refutation

The instinctive reading — "building housing barely reduces homelessness" — overstates what the paper shows, and it is important to state the limits honestly:

• PSH is a targeted intervention, not a market-rent shift. Permanent supportive housing is deeply subsidized, service-intensive housing rationed to a specific (often chronically homeless, disabled) subpopulation. Its bed count is not the same margin as the market rent level and rental vacancy rate that drive the cross-community geography of homelessness. Corinth's small PSH coefficient therefore does not contradict the finding that high-rent, low-vacancy markets have more homelessness — it addresses a different question (does this program shrink the count?).
• Flow, not just stock. The fade-out is concentrated in short-spell homelessness, consistent with search-and-flow models (O'Flaherty and others in Corinth's references): a subsidized unit that houses one person can be offset by continued inflows into a tight market, so the stock moves less than the number of beds. This is a reason the market-conditions story matters — a loose, cheap market both lowers inflows and makes each intervention stick.
• It genuinely tempers optimistic supply readings. With that scope stated, the paper is a real check on any claim that homelessness can be ended simply by adding units at the current margin without regard to the surrounding housing market — which is why it belongs in the outcome page's challenged_by, not its supported_by.

Bears On

• Outcome: Homelessness is a housing-cost problem — listed in that page's challenged_by: it complicates the intervention corollary of the housing-cost thesis.
• Quigley, Raphael & Smolensky (2001) and Hanratty (2017) — the market-level results Corinth's finding qualifies but does not overturn.
• Colburn & Aldern, Homelessness Is a Housing Problem — the anchor book, whose two-level (who vs. how many) framing helps reconcile Corinth's small program effect with the strong rent-geography relationship.

See Also

• Outcome: Homelessness is a housing-cost problem
• Narrative: The Housing Crisis Is a Land Crisis
• Outcome: LVT improves housing affordability

Sources

1. Kevin Corinth (2017), "The impact of permanent supportive housing on homeless populations," Journal of Housing Economics 35: 69–84. DOI: 10.1016/j.jhe.2017.01.006. Abstract via RePEc/IDEAS and AEI — used for the 2007–2014 panel design, the 0.04–0.12 association, and the IV estimate (≤0.10, upper bound 0.72 rejected at 95%); fetched and read 2026-07-11.
2. Kevin Corinth (2015), "Ending Homelessness: More Housing or Fewer Shelters?", AEI Economic Policy Working Paper 2015-12. aei.org PDF — used for the first-year 0.12 effect and its full muting after the first year, driven by the shorter-spell subpopulation; abstract fetched and read 2026-07-11.