Skip to main content
Ending and Preventing

With pioneering measurement methods and hands-on technical assistance, we are working


to drive federal, state, and community action on homelessness





Lauren Dunton, Associate Scientist, Social and Economic Policy Division


Watch Lauren discuss Abt's contribution to bringing around an end to homelessness across the U.S.





Until 2000’s there was no clear understanding of the national prevalence or nature of homelessness, nor a common vision for what it meant to "end" it.

Beginning in 2001, we pioneered a method of producing reliable, national estimates of homelessness, and describing the characteristics of those experiencing it.

This approach has been used for more than a decade to understand homelessness in America.

For more than 10 years, we have created the Annual Homeless Assessment Report (AHAR), the definitive two part report to the U.S. Congress on behalf of the U.S. Department of Housing and Urban Development (HUD). The report assesses the nation’s progress against the Federal Strategic Plan to Prevent and End Homelessness.

AHAR Part 1: provides estimates of homelessness based on Point-in-Time (PIT) count data, which estimates the number of people experiencing sheltered and unsheltered homelessness on a single night in January.

AHAR Part 2: builds on Part 1 by adding 1-year estimates of sheltered homelessness and describes the characteristics of those experiencing homelessness, based on data from local Homeless Management Information Systems (HMIS).

I can say from my own firsthand experience inside of the government that there is a straight line between the AHAR and improving the lives of our most vulnerable community members.

Ann M. Oliva
former Director of the Office of Special Needs Assistance Programs (SNAPS) and Deputy Assistant Secretary for Special Needs, U.S. Department of Housing and Urban Development

Data enables a deeper understanding of the prevalence and nature of homelessness across populations.

People Experiencing Homelessness (PIT) in the United States Total Homeless Population, All
Show trend lines by None Subpopulation Geography Type

Imagine a homeless services system in which...the housing programs are designed to match the needs and preferences of people in the community...a coordinated approach ensures the most vulnerable people get the help they drives continuous improvement. Through our system modeling and on-the-ground support, we are helping to make this vision a reality in communities across the U.S.


More than 150,000 families with children experience homelessness each year.

How do we best help these families?


Through the Family Options Study, we conducted a national evaluation involving more than 2,300 families across 12 sites in the U.S.. The families were assigned randomly to one of three approaches meant to help families leave homelessness, and a "usual care" group.

The study provided conclusive evidence about the effectiveness of long-term housing subsidies as the best way to end homelessness. It also confirmed that communities and funders should move away from a transitional housing approach in which families stay in a facility and receive intensive services. This approach is more expensive and had no better results than other options.


Providing priority access to long-term housing subsidies helps keep families who enter emergency shelters from becoming homeless again. These housing subsidies lead to additional positive benefits such as reducing food insecurity, school moves for children and intimate partner violence.


People with chronic patterns of homelessness are often the most visible of those experiencing homelessness, as they often stay on the street, in abandoned buildings or in encampments. People homeless for a long time--or repeatedly-- tend to be heavy users of costly public services, including jails, detox centers and emergency rooms.


Permanent supportive housing-housing with security of tenure linked to services most needed by vulnerable people - can break the cycle of chronic homelessness.


On a single night in January 2017, California accounted for 42 percent of all individuals experiencing chronic homelessness in the U.S., with LA County experiencing a particularly high proportion. The Conrad N. Hilton Foundation’s Chronic Homelessness Initiative has been working on addressing the issue in Los Angeles since 2010, and has asked Abt to independently evaluate its strategy and progress.



Our formative evaluation of the Chronic Homelessness Initiative is informing county-wide systems change that is producing more supportive housing for use by the people who need it most, when they need it. In addition to producing a quantitative assessment of progress, we tracked indicators in major areas of focus for major areas of focus for stakeholders over the next five years to end chronic homelessness in LA. These include political will, scaling up the housing and service resources, building a county-wide prioritization system, and understanding the impact of inflow on the population.

In addition to the evaluation, our direct technical assistance team works closely with the Los Angeles Services Authority to apply a system modeling approach to analyze demand for homeless assistance, quantify resource gaps, and scale up outreach. The cohesive, coordinated approach ensures that system-decision making is effective, and that the most vulnerablepeople do not slip through the cracks but instead receive the help they need.


On a single night in January 2017, 40,056 veterans were experiencing homelessness in the U.S. — just over 9 percent of all homeless adults. The U.S. federal government and communities across the nation are focusing resources on preventing and ending Veteran homelessness.


Permanent supportive housing, case management and short-term assistance are critical to preventing and ending Veteran homelessness.


The HUD-Veterans Affairs Supportive Housing (VASH) program has demonstrated that permanent supportive housing that uses Section 8 Housing Choice Vouchers works for Veterans with disabling conditions -- just as our earlier research indicated that the housing voucher approach works for vulnerable people generally.

Additional mobilization of resources through programs like VA's Supportive Services for Veterans' Families (SSVF) and HUD's Vets@Home have been instrumental in bringing down Veteran homelessness by 45 percent since 2009.


In dozens of communities across the U.S., we are bringing together local stakeholders to identify key barriers to ending homelessness among veterans and creating community-specific systems to overcome these barriers.

In addition to direct technical assistance, we have developed robust tools, with a focus on improving community crisis response systems. To further enhance community capacity, we developed a Master List Template and Benchmark Generation Tool that makes it easier for communities to identify criteria and measure their progress toward effectively ending veteran homelessness.

As a result of this work, several of the communities that we have worked with, - including Dayton, recognized by the United States Interagency Council on homelessness for veterans.


According to the point-in-time counts, 40,799 unaccompanied youth and young adults experienced homelessness on a single night in January 2017. Yet, assessing the full extent and nature of the homeless youth population is particularly challenging.


Youth (under 18) and young adults (18 to 25) may experience homelessness differently from adults. It may start with their aging out of foster care, running away from an abusive home, or parental rejection-a situation to which LGBTQ youth are particularly vulnerable. Vulnerable youth may show up in emergency shelters for adults, or just "couch surf" or stay with an adult who is exploiting or trafficking them.

Programmatic definitions of homelessness for youth vary across federal agency, and fail to capture all those who are eligible, by definition, for their services.


Better understanding, and a coordinated strategic approach, is critical to addressing youth and young adult homelessness.

We are researching and synthesizing evidence on programmatic approaches, being used to serve young people experiencing homelessness.

In one evaluation, we are tracking a sample of youth who use transitional housing programs funded by the Department of Health and Human Services to help better understand the challenges and experiences of youth who experience homelessness.


Through our technical assistance efforts, we help communities design data-informed system responses to prevent and end homelessness for youth and young adults.

In the District of Columbia, we helped developed DC's Interagency Council on Homelessness' strategic plan to end youth homelessness. With the adoption of the five year strategic plan, the District became one of the first cities in the U.S. to adopt a data-driven strategy for ending youth homelessness. Our system modeling helped shape the plan's recommendations, including analysis of the number of young people who experience homelessness in the District each year, the programs they are likely to access, and the length of time they are likely to stay enrolled in each program.

We are undertaking similar efforts through our technical assistance to two of HUD's Youth Homelessness Demonstration Program grantees. We helped both sites develop coordinated community plans with projections of the type and level of resources needed to comprehensively address youth homelessness.