California Statewide Study of People Experiencing Homelessness
The California Statewide Study of People Experiencing Homelessness (CASPEH), conducted by The University of California, San Francisco Benioff Homelessness and Housing Initiative (BHHI), is the largest representative study of homelessness in the United States since the mid-1990s. The study provides a comprehensive look at the causes and consequences of homelessness in California and recommends policy changes to shape programs in response. #CAHomelessnessStudy
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Designed to be representative of all adults 18 years and older experiencing homelessness in California, CASPEH includes nearly 3,200 administered questionnaires and 365 in-depth interviews with adults experiencing homelessness in eight regions of the state, representing urban, rural, and suburban areas. Interviews were conducted in English and Spanish, with interpreters for other languages. In partnership with a wide array of community stakeholders, the UCSF BHHI team collected data between October 2021 and November 2022. CASPEH was funded by UCSF BHHI, the California Health Care Foundation, and Blue Shield of California Foundation.
CASPEH is a cross-sectional study—a study that happened at a single point in time. Cross-sectional studies of homelessness seek to answer questions related to the experiences of those who are homeless at one point in time. This is a different question than asking “what are the experiences of people who were homeless at any point this year?” Because most homelessness episodes are short, people who are homeless for longer periods are more likely to be homeless at any one given point in time. People with behavioral health conditions are more likely to be homeless for longer periods, and thus more likely to be in cross-sectional studies. Studies that ask different questions, such as “what percentage of people who are homeless at any time during this year have a behavioral health problem” will have lower rates of behavioral health problems.
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Special Reports
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Reports
Toward Thriving: Understanding Health and Homelessness
November 18, 2025
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Reports
Toward Equity: Latine Experiences of Homelessness
June 11, 2025
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Latine Californians represent more than one-third of the state's homeless population. Yet their experiences are too often left out of research, policy, and service design.
To better understand these experiences, we examined data from the California Statewide Study of People Experiencing Homelessness. This report, based on the California Statewide Study of People Experiencing Homelessness (CASPEH), examines who experiences homelessness in the Latine community, their experiences while homeless, and offers evidence-based policy and program solutions.
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Reports
Behavioral Health and Homelessness
March 19, 2025
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Behavioral health challenges both contribute to and are exacerbated by homelessness. To better understand behavioral health and homelessness, we examined data from the California Statewide Study of People Experiencing Homelessness. Our latest report examines the relationship between homelessness, substance use, and mental health, providing critical insights for policymakers, program leaders, Continuum of Care leaders, and healthcare systems.
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Topic Brief
Unsheltered Homelessness
September 12, 2024
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This topic brief examines who experiences unsheltered homelessness, how they lost their housing, their experiences during homelessness, and barriers to regaining housing. The findings highlight the urgent need for the homelessness system to advance evidence-based strategies to meet the needs of unsheltered people.
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Topic Brief
Pregnancy and Homelessness
July 25, 2024
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This topic brief examines who experiences pregnancy during homelessness, how they lost their housing, their experiences during homelessness, and obstacles to regaining housing. The findings highlight the urgent need for the homelessness system to advance evidence-based strategies to meet the reproductive health needs of people experiencing homelessness.
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Reports
Toward Dignity: Understanding Older Adult Homelessness
May 23, 2024
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To better understand the experiences of older adults experiencing homelessness, the UCSF Benioff Homelessness and Housing Initiative examined findings from the California Statewide Study of People Experiencing Homelessness (CASPEH), the largest representative study of homelessness since the mid-1990s. This report reviews who experiences homelessness in late life, how they lost their housing, their experiences during homelessness, and the barriers they face to regaining housing. These findings highlight the urgent need for research-backed solutions and policy interventions to address the unique challenges faced by older adults experiencing homelessness.
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Reports
Toward Equity: Understanding Black Californians’ Experiences of Homelessness
February 21, 2024
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Reports
Toward Equity: Understanding Black Californians’ Experiences of Homelessness
February 21, 2024
To better understand the experiences of Black Californians experiencing homelessness, the UCSF Benioff Homelessness and Housing Initiative examined the experience of Black Californians within the California Statewide Study of People Experiencing Homelessness (CASPEH), the largest representative study of homelessness since the mid-1990s. This report reviews who experiences homelessness in the Black community, what may have precipitated their homelessness, experiences during their episode of homelessness, and what impacts their return to permanent housing. These findings aim to inform evidence-based solutions for preventing and ending homelessness for Black Californians.
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Reports
Toward Safety: Understanding Intimate Partner Violence and Homelessness
January 16, 2024
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To better understand the experiences of survivors of intimate partner violence currently experiencing homelessness, this report analyzed data related to IPV in the California Statewide Study of People Experiencing Homelessness (CASPEH)—the largest representative study of homelessness since the mid-1990s. The mixed-methods study included data about participants’ experiences of violence across the life course, in the six months prior to homelessness, and during their current episode of homelessness. The report presents these findings to advance research-backed solutions for preventing and responding to homelessness among survivors of IPV.
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Our Research
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Our Research
Tobacco Use Patterns and Missed Opportunities for Cessation Treatment Among People Experiencing Homelessness
June 30, 2025
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Our Research
Tobacco Use Patterns and Missed Opportunities for Cessation Treatment Among People Experiencing Homelessness
June 30, 2025
People experiencing homelessness have significantly lower life expectancies than the general population, and among those aged ≥ 45, tobacco-related illnesses are the leading cause of death.[1] Compared to the general population, tobacco use among people experiencing homelessness is six times higher, and the quit ratio (ratio of former to ever-smokers) is five times lower. [2],[3] We used the largest representative study of people experiencing homelessness since the 1990s to estimate tobacco use prevalence and its association with shelter status, behavioral health, and health services use among adults experiencing homelessness in California to identify opportunities to address unmet tobacco treatment needs.
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Our Research
Illicit Substance Use and Treatment Access Among Adults Experiencing Homelessness
February 19, 2025
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Our Research
Illicit Substance Use and Treatment Access Among Adults Experiencing Homelessness
February 19, 2025
Most people experiencing homelessness in California are not regular drug users — and for some, substance use begins or worsens after losing housing. Some use drugs to stay awake and safe, coping with the trauma and danger of life without shelter.
At the same time, many who want treatment can’t get it.
This paper uses data from the California Statewide Study of People Experiencing Homelessness to show a comprehensive, representative look at substance use, overdose risk, and unmet treatment needs among people experiencing homelessness in California.
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Our Research
Experience of Violence During Homelessness
October 14, 2024
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This research letter discusses the experience of violence during homelessness, its impact on health, and recommendations for intervention. In the California Statewide Study of People Experiencing Homelessness, 38% of participants experienced violence during their current homelessness episode, and 74% of participants reported experiencing violence at some point in their lives. These results highlight the need to address violence against people experiencing homelessness through safer housing options, trauma-informed care, and long-term violence prevention strategies.
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Our Research
Novel Methods to Construct a Representative Sample for Surveying California’s Unhoused Population: The California Statewide Study of People Experiencing Homelessness
September 11, 2024
Existing literature on people experiencing homelessness (PEH) draws on non-representative samples from service providers, populations with comorbidities, or areas with disproportionately high sheltered homelessness, leading to bias. Nearly a third of PEH in the US and over half of unsheltered PEH live in California. Researchers from the UCSF Benioff Homelessness and Housing Initiative designed a rigorous state-representative survey of PEH to investigate the antecedents of homelessness, understand health, and inform policy solutions. This is the first large representative study of PEH, beyond a single county, to draw inference on a large population that did not depend on service utilization.
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Related Content
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Videos
Webinar: Understanding Health & Homelessness
December 9, 2025
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People experiencing homelessness in California face high rates of chronic illness and disability, and numerous barriers to care. These health challenges make it harder for people to obtain and retain housing, and homelessness worsens health, trapping people in a vicious cycle. As the homeless population ages, these burdens deepen, with profound implications for individuals, communities, and the systems that serve them.
This webinar includes findings from our recent report, Toward Thriving: Understanding Health & Homelessness, with insights from the report’s lead author and experts from across the health and homelessness systems.
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Reports
Toward Thriving: Understanding Health and Homelessness
November 18, 2025
Read the Full Article
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Press Release
New UCSF BHHI Report Finds High Rates of Chronic Disease and Disability Among Californians Experiencing Homelessness
November 18, 2025
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Press Release
New UCSF BHHI Report Finds High Rates of Chronic Disease and Disability Among Californians Experiencing Homelessness
November 18, 2025
The University of California, San Francisco Benioff Homelessness and Housing Initiative (BHHI) today released a report on the relationship between health and homelessness.
Toward Thriving: Understanding Health & Homelessness reveals that nearly half of Californians experiencing homelessness rate their health as poor or fair—about four times the rate in the general U.S. population. The report documents high rates of chronic disease, disability, and steep barriers to care for Californians experiencing homelessness.
Read the Full Article
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Reports
Toward Equity: Latine Experiences of Homelessness
June 11, 2025
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Latine Californians represent more than one-third of the state's homeless population. Yet their experiences are too often left out of research, policy, and service design.
To better understand these experiences, we examined data from the California Statewide Study of People Experiencing Homelessness. This report, based on the California Statewide Study of People Experiencing Homelessness (CASPEH), examines who experiences homelessness in the Latine community, their experiences while homeless, and offers evidence-based policy and program solutions.
Read the Full Article
