The Size and Census Coverage of the U.S. Homeless Population
Despite widespread concern about homelessness, fundamental questions about the size and characteristics of this hard to study population are unresolved, in large part because it is unclear whether existing data are sufficiently complete and reliable. We examine these questions as well as the coverage of new microdata sources that are designed to be nationally representative and will allow pathbreaking new analyses. We compare three restricted use data sources that have been largely unused to study homelessness to less detailed public data. In doing this triangulation of sources, we examine the completeness and accuracy of available data and improve our understanding of the size of the homeless population and its inclusion in household surveys. Specifically, we compare restricted data from the 2010 Census, American Community Survey (ACS), and Homeless Management Information System (HMIS) to HUD's public-use point-in-time (PIT) estimates and the Housing Inventory Count (HIC) at the national, city and county, and person level. We explore the extent to which definitions, weighting, frame completeness, and seasonality explain discrepancies between sources. We also link HMIS shelter-use data to the Census to evaluate the usefulness of these microdata to study this population. Our analyses suggest that on a given night there are 500,000-600,000 people experiencing homelessness in the U.S., about one-third of whom are sleeping on the streets and two-thirds in shelters. About 80-95 percent of those in shelters were counted in the Census. Despite employing substantially different methods, the Census, ACS, and PIT arrive at similar estimates after accounting for definitional differences, ambiguity in the classification of certain facilities, and differences arising from the timeframe of Census response. The coverage of these sources is surprisingly good given the difficulties of surveying this population. By establishing the broad coverage and reliability of the new data sources, this paper lays the foundation for pathbreaking future work on the characteristics, income, safety net participation, mortality, migration, geographic distribution, and housing status transitions of the U.S. homeless population.
This paper, which has been subject to a limited Census Bureau review, is released to inform interested parties of research and to encourage discussion. Any opinions and conclusions expressed herein are those of the authors and do not represent the views of the U.S. Census Bureau. The Census Bureau has reviewed this data product for unauthorized disclosure of confidential information and has approved the disclosure avoidance practices applies to this release, authorization numbers: CBDRB-FY20-ERD002-004, CBDRB-FY2022-CES005-006, and CBDRB-FY2022-CES005-008. We thank the U.S. Census Bureau for their support and thank John Abowd, Mark Asiala, George Carter, James Christy, Dennis Culhane, Kevin Deardorff, Conor Dougherty, Ingrid Gould Ellen, Anne Fletcher, Katie Genadek, Kristin Kerns, William Koerber, Margot Kushel, Larry Locklear, Tim Marshall, Brian McKenzie, Brendan O’Flaherty, James Pugh, Trudi Renwick, Annette Riorday, Nan Roman, William Snow, Eddie Thomas, and John Voorheis for providing feedback and answering our questions and Gillian Meyer, Connor Murphy, and Sophie Yang for research assistance. We appreciate the financial support of the Alfred P. Sloan Foundation, the Russell Sage Foundation, the Charles Koch Foundation, the Menard Family Foundation, and the American Enterprise Institute. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.