Congress first provided a general definition of homeless individuals in 1987 in what is now called the McKinney-Vento Act. In 2002, Congress added a definition for homeless children and youths to be used in educational programs. Prior to the enactment of the HEARTH Act, the McKinney-Vento Act generally defined a homeless individual (McKinney- Vento Individual) as someone who lacks a fixed, regular, and adequate nighttime residence and has a nighttime residence that is a supervised shelter designed to provide temporary accommodations; an institution providing a temporary residence for individuals awaiting institutionalization; or a place not designed for, nor ordinarily used as, a regular sleeping accommodation. However, in the provisions on education of children and youths, the McKinney-Vento Act also specifically included children and youths who are sharing the housing of other persons due to loss of housing, economic hardship, or a similar reason (that is, are doubled up); living in motels, hotels, trailer parks, or camping grounds due to the lack of alternative adequate accommodations awaiting foster care placement; or living in substandard housing (McKinney-Vento Children and Youth). For its homeless assistance programs, HUD has interpreted the McKinney- Vento Act definitions so that a homeless individual is someone who resides in places not meant for human habitation, such as in cars, abandoned buildings, housing that has been condemned by housing officials, or on the street, in an emergency shelter or transitional or supportive housing, or any of these places, but is spending a short time (up to 30 consecutive days) in a hospital or other institution. Additionally, individuals are considered homeless if they are being evicted within a week from a private dwelling and no subsequent residence has been identified and the person lacks the resources and support networks needed to obtain housing; discharged within a week from an institution in which the person has been a resident for 30 or more consecutive days and no subsequent residence has been identified; or fleeing a domestic violence situation. The HEARTH Act includes changes in the general definition of homelessness, but the new definition and associated regulations had not taken effect by June 2010. The HEARTH Act broadened the general definition and provided greater statutory specificity concerning those who should be considered homeless but did not change the McKinney-Vento Children and Youth definition. For example, the HEARTH Act definition includes individuals and families that will be evicted in, or who can otherwise demonstrate that they will not be able to remain in their current living place for more than, 2 weeks. The HEARTH Act definition includes some individuals, families, and youths who would have been considered homeless under the McKinney-Vento Children and Youth definition but not under the prior individual definition. Some federal programs that were authorized outside of the McKinney- Vento Act use other definitions of homelessness. For example, the Runaway and Homeless Youth Act, first introduced as the Runaway Youth Act of 1974, defined a homeless youth as being generally from the ages of 16 to 22, unable to live in a safe environment with a relative, and lacking any safe alternative living arrangements. Within various programs, the definition of homelessness determines whether individuals are eligible for program benefits. For the Education of Homeless Children and Youth program, meeting the definition entitles the student to certain benefits; however, in other cases, such as HUD’s homeless assistance programs or HHS’s Runaway and Homelessness Youth programs, benefits are limited by the amount of funds appropriated for the program. For these programs, meeting the definition of homelessness does not necessarily entitle individuals or families to benefits. In addition, programs have other eligibility criteria, such as certain income levels, ages, or disability status. As illustrated in table 1, programs that provide targeted assistance primarily to those experiencing homelessness have different purposes, definitions of homelessness, and funding levels. One of these programs, HUD’s Homeless Prevention and Rapid Rehousing Program, was created under the American Recovery and Reinvestment Act (Recovery Act) of 2009, and many others received additional funding under that act. HUD’s Homeless Assistance Programs comprise a number of individual programs. These include the Emergency Shelter Grant Program, under which funding is provided on a formula basis, and competitive programs funded under the umbrella of the Continuum of Care (Continuum). The latter include the Supportive Housing, Shelter Plus Care, and Single Room Occupancy Programs. A Continuum is a group of providers in a geographical area that join to provide homeless services and apply for these grants. The Continuum is also responsible for planning homeless services, setting local priorities, and collecting homelessness data. Additionally, many federally-funded mainstream programs provide services for which those experiencing homelessness may be eligible. Some of these programs are required to provide services to those experiencing homelessness and may define it, others allow local providers to choose to target certain services to those experiencing homelessness or provide homelessness preferences using locally determined definitions, and still other programs do not distinguish between those experiencing homelessness and those not experiencing it (see table 2). The McKinney-Vento Act also authorized the creation of the U. S. Interagency Council on Homelessness (Interagency Council). Initially, the main functions of the Interagency Council revolved around using public resources and programs in a more coordinated manner to meet the needs of those experiencing homelessness. The McKinney-Vento Act specifically mandated the council to identify duplication in federal er programs and provide assistance to states, local governments, and oth public and private nonprofit organizations to enable them to serve those experiencing homelessness more effectively. In the HEARTH Act, the council, which includes 19 agencies, was given the mission of coordinat the federal response to homelessness and creating a national partnersh at every level of government and with the private sector to reduce and end ip homelessness. This act also mandates that the Interagency Council develop and annually update a strategic plan to end homelessness. Several agencies overseeing targeted homelessness programs are required to collect data on segments of the homeless population. As illustrated in table 3, HUD, HHS, and Education all have met their requirements through their own data collection and these sources differ in housing data collected and level of aggregation. In addition, the data collected necessarily reflect the definitions of homelessness included in the statutes that govern the relevant programs. Under the McKinney-Vento Act, HUD is to develop an estimate of homeless persons in sheltered and unsheltered locations at a 1-day point in time, so HUD requires Continuums to conduct a count of the sheltered and unsheltered homeless in their jurisdictions in January of every other year. Additionally, pursuant to the 2001 amendments to the McKinney-Vento Act, HUD was to develop a system to collect and analyze data on the extent of homelessness and the effectiveness of McKinney-Vento Act programs. As a result, HUD developed a set of technical data standards for the Homelessness Management Information System (HMIS), which sets minimum privacy, security, and technical requirements for local data collection on the characteristics of individuals and families receiving homelessness services. HMIS data standards allowed communities to continue using locally developed data systems and adapt them to meet HUD standards. Local Continuums are responsible for implementing HMIS in their communities, and Continuums can choose from many HMIS systems that meet HUD’s data standards. HUD officials said that by allowing Continuums to choose from multiple systems, more service providers participate and Continuums and service providers can modify existing systems to meet HUD standards and the community’s goals. Continuums report aggregated data to HUD annually. Results from analysis of the point-in-time count and HMIS data are reported in HUD’s Annual Homelessness Assessment Report to Congress. Pursuant to the Runaway and Homeless Youth Act, HHS requires all service providers to collect data on youths who receive services through the Runaway and Homeless Youth Program. Grantees submit these data every 6 months to the Runaway and Homeless Youth Management Information System (RHYMIS), a national database that includes unidentified individual-level data. To demonstrate compliance with the Elementary and Secondary Education Act of 1965, Education requires states to complete Consolidated State Performance Reports that include data on homeless children and youths being served by Elementary and Secondary Education Act programs and the Education of Homeless Children and Youth Program, as amended. The McKinney-Vento Act requires local school districts to have homelessness liaisons, who work with other school personnel and those in the community to identify homeless children and youths, provide appropriate services and support, and collect and report data. States aggregate local data and report to Education annually cumulative numbers of homeless students enrolled in public schools by grade and primary nighttime residence. As part of its decennial population and housing census, the U.S. Census Bureau has programs designed to count people experiencing homelessness. The Census counts people at places where they receive services (such as soup kitchens or domestic violence shelters), as well as at targeted nonshelter outdoor locations. While the Census makes an effort to count all residents, including those experiencing homelessness, the 2010 Census does not plan to report a separate count of the population experiencing homelessness or a count of the population who use the services. Although federal agencies collect data on those experiencing homelessness, these data have a number of shortcomings and consequently do not capture the true extent and nature of homelessness. Some of these shortcomings derive from the difficulty of counting a transient population that changes over time, lack of comprehensive data collection requirements, and the time needed for data analysis. As a result of these shortcomings, the data have limited usefulness. Complete and accurate data are essential for understanding and meeting the needs of those who are experiencing homelessness and to prevent homelessness from occurring. According to HUD, communities need accurate data to determine the extent and nature of homelessness at a local level, plan services and programs to address local needs, and measure progress in addressing homelessness. HUD needs accurate data to fulfill its reporting obligations to Congress and to better understand the extent of homelessness, who it affects, and how it can best be addressed. HUD’s point-in-time count is the only data collection effort designed to obtain a national count of those experiencing homelessness under the McKinney-Vento Individual definition, and approximately 450 Continuums conduct a point-in-time count in January of every other year. However, service providers and researchers we interviewed expressed concerns about the ability of HUD’s point-in-time count to fully capture many of those experiencing homelessness for reasons including the following: People experiencing homelessness are inherently difficult to count. They are mobile, can seek shelter in secluded areas, and may not wish to attract the notice of local government officials. Point-in-time counts do not recognize that individuals and families move in and out of homelessness and can experience it for varying lengths of time. These counts more likely count those experiencing homelessness for long periods rather than those experiencing it episodically or for short periods. Although homelessness can be episodic, the count is done biennially in January, which might lead to an undercount of families because landlords and others may be reluctant to evict families when the weather is cold or school is ongoing. Count methodologies vary by Continuum, can change from year to year, and might not be well implemented because counters are volunteers who may lack experience with the population. Large communities do not necessarily attempt to count all of those experiencing homelessness but rather may use estimation procedures of varying reliability. HUD provides technical assistance to communities, which helps them to develop and implement point-in-time count methodologies, and HUD officials said that methodologies and the accuracy of the count have improved. Additionally, HUD officials said that as part of their quality control efforts, they contacted 213 Continuums last year to address errors or inconsistencies in their data from fiscal year 2008. A communitywide point-in-time count demands considerable local resources and planning, and communities rely on volunteers to conduct counts of the unsheltered population. Continuums do not receive any funding from HUD to conduct the point-in-time counts, and using professionals or paid staff to conduct the count could be costly. Other federal data collected on those experiencing homelessness primarily or only captures clients being served by federally-funded programs. As a result, federal data do not capture some people seeking homeless assistance through nongovernmental programs, or others who are eligible for services but are not enrolled. For instance, while HUD grantees are required to participate in HMIS, participation is optional for shelters that do not receive HUD funding. HUD can use the annual Continuum funding application to assess the extent to which those shelters not receiving HUD funding participate in HMIS. In their funding applications Continuums provide an inventory of shelter beds in their community and also provide the percentage of those beds that are located in shelters that participate in HMIS. HMIS participation rates vary widely across communities and shelter types. For example, one of the locations we visited reported data for less than 50 percent of its beds for transitional shelters, while another reported data for more than 75 percent of its beds. HUD officials said that while some Continuums have been slower to implement HMIS and receive full participation from their providers than others, according to HUD’s 2009 national housing inventory data of homeless programs, 75 percent of all shelter beds were covered by HMIS, including programs that do not receive HUD funding. The Violence Against Women Act prohibits service providers from entering individual-level data into HMIS for those in domestic violence shelters. Similarly, RHYMIS collects data on those clients using its residential systems, but these serve only a small percentage of the estimated number of youths experiencing homelessness. HHS officials stated that nationwide, they only fund approximately 200 transitional living centers for young adults. Education also does not fully capture the extent of homelessness among school-aged children because all of the districts we visited used a system of referrals and self-reporting to identify those children. In one of the school districts we visited, an official said that, based on estimates of the number of children experiencing homelessness under the McKinney-Vento Children and Youth definition, the district was serving about half of those students. Many of the school officials and advocates with whom we spoke said the term homelessness carried a stigma that made people reluctant to be so identified, and two school systems had removed the word from the name of their programs. Additionally, federal data systems on homelessness may count the same individual more than once. HUD designed HMIS to produce an unduplicated count—one that ensures individuals are counted only once— of those experiencing homelessness within each Continuum. Providers in the same Continuum use the same HMIS system and some Continuums have designed an open system, where providers can view all or part of an individual’s record from another provider within the Continuum. This is useful to providers because it helps them to understand an individual or family’s service needs. It also allows them to produce an unduplicated count of those using services in the Continuum because every person receiving services in the Continuum has a unique identifier in HMIS. However, it is difficult to share data across Continuums and this can be done only if Continuums have signed agreements that protect privacy and are using the same HMIS system. Thus, clients may be entered into HMIS in more than one Continuum and counted more than once. Nonetheless, some states have constructed statewide HMIS systems to help avoid duplication in the data. Because RHYMIS has individual data on all program recipients in a single database, HHS can obtain an accurate count on the number of youths served by its residential programs. Education data also may be duplicative. Because students generally are counted as homeless if they experience homelessness at any point during the school year, if they change school districts during the year, they could be counted as homeless in both systems. While each agency makes efforts to avoid duplication in its data, it is not possible to determine how many total unique individuals federal homelessness programs have served because HUD, HHS, and Education data systems generally do not interface or share data. Further, the data in HMIS may not always accurately reflect the demographic information on families and individuals seeking shelter. For example, HMIS provides data for individuals and families but the system may not accurately identify family members and track the composition of families over time. Using HMIS, service providers associate individuals entering into a shelter with a family if family members enter the shelter together. However, some families split up to obtain shelter, so the system would not track all families over time. In one of our site visit locations, we met a mother and son who were split up and placed in separate shelters. Because the mother was in an individual shelter, and the son was in a youth shelter, HMIS would not associate these two as a family. Further, one service provider we spoke with said that HMIS may not always accurately track demographic information on individuals seeking emergency shelter. Some researchers and advocates told us that HMIS’s design limited its usefulness, and the extent to which service providers found that the HMIS system their Continuum had implemented was useful varied across the four locations we visited. For example, a researcher who has extensively used HMIS told us that if service providers used the data they collected for HMIS to manage their programs, they would implement processes to help ensure data quality. But in three of the four locations we visited, many providers said they were unable to use HMIS for program administration and client case management. Many providers noted that they often had to enter information in several different databases, and they generally used their own database to administer their programs. Additionally, we found only two providers who developed data export tools that allowed their private systems to upload data to HMIS, and in both cases, the providers were unable to use their new tools after the Continuum switched HMIS software. HHS officials told us that they support providers’ development of tools to link data systems, but they do not provide funding for this endeavor. In contrast, service providers in one location we visited reported that the HMIS system they had adopted had options that allowed them to conduct comprehensive case management for clients and produce all of the reports required by the various organizations funding their programs and operations. HUD officials said that a community’s success in using HMIS for program administration and client case management depends on a variety of factors including staff capability and the quality of the HMIS software that they chose to purchase or develop. HUD and Education data also have shortcomings and limited usefulness because of the time lag between initial data collection and the reporting of the data. HUD published the most recent report to Congress, which provided data for October 2008–September 2009, in June 2010. Education expected to publish data for the 2008–2009 school year in June 2010. Because of the time lag in availability of HUD and Education data, they have limited usefulness for understanding current trends in homelessness and the ongoing effects of the recession. However, HUD officials report that they have made progress in reducing the time it takes to analyze data and publish its annual report to Congress. The time lag from data collection to report issuance has decreased from almost 2 years to less than 1 year, but collecting data on homelessness and producing national estimates takes time, and HUD officials said there will always be some time lag. Additionally, in recognition of these shortcomings, HUD recently introduced the Homeless Pulse Project, which collects quarterly homeless shelter data from nine communities. These communities volunteered to submit data on a more frequent basis, but they are not representative of Continuums nationwide. HUD plans to expand the Pulse Project and add approximately 30 Continuums that have volunteered to participate. HHS’ RHYMIS data are more timely because grantees submit data every 6 months, and HHS makes the data available online approximately 1 month after the end of the reporting period. Although a researcher with special expertise in HMIS and several advocates we interviewed cited some examples of incompleteness or inaccuracy in HMIS data, agencies and Continuums have been trying to improve the completeness and accuracy of their data. For example, HUD provides incentives for Continuums to increase HMIS participation rates. In its competitive grant process, HUD evaluates the level to which Continuums participate in HMIS. HUD officials have also provided technical assistance to Continuums to assist them in increasing local HMIS participation rates. HMIS rates have increased over time. Several Continuums we contacted have been conducting outreach to private and faith-based providers to encourage them to use HMIS to improve data on homelessness. Additionally, according to HUD officials, HMIS data have been used to conduct research on the prevalence of homelessness, the costs of homelessness, and the effectiveness of interventions to reduce homelessness. Further, HUD supplements HMIS data with point-in-time data to enhance the information available on those experiencing homelessness. HHS has begun a project to get some of its homelessness programs to use HUD’s HMIS system. For example, as discussed in more detail further on, in December 2009, HHS established an agreement with HUD requiring PATH providers to use HMIS. To address the issues faced by emergency shelters in quickly collecting and entering data on individuals, some Continuums issue identification cards containing demographic information to clients during their initial intake into the shelter system. Clients can swipe the cards as they enter a facility, and HMIS automatically captures the data. Despite the limitations discussed above, HUD uses data from point-in-time counts to estimate the number of those experiencing homelessness on a single night in January. HUD reported that approximately 660,000 individuals and persons in families experienced sheltered and unsheltered homelessness on a single night in January 2008. However, this estimate does not include people who do not meet the definition of homelessness for HUD’s programs but do meet definitions of homelessness for other programs. For example, HUD’s counts would not include families living with others as a result of economic hardship, who are considered homeless by Education. Figure 1 shows the count of sheltered and unsheltered persons s experiencing homelessness on a single night in January for the past 4 years. experiencing homelessness on a single night in January for the past 4 years. HUD also samples a number of communities and uses their HMIS data to estimate those experiencing homelessness in shelters during the year. HUD estimated that in 2008, 1.18 to 2 million people met HUD’s definition of homelessness and were sheltered at some time in the year. The estimate has a broad range because HUD uses a sample of 102 communities and not all of those communities can provide usable data. For those Continuums related to the communities that can provide data on at least half of the beds in their inventory, HUD assumes that the remaining beds would be occupied in similar ways to estimate shelter use for those Continuums that cannot provide such data. HUD officials noted that response rates have been steadily improving and the estimate’s range has decreased. For example, in 2008, 87 of the 102 communities in HUD’s sample provided usable data and another 135 communities voluntarily submitted data; while in 2005, 55 communities in a sample of 80 communities provided usable data and another 9 communities contributed data voluntarily. HUD estimates that individuals without children make up about two-thirds and families with children under 18 about one-third of the estimate. However, HMIS only captures individuals and families who are defined as homeless under the McKinney-Vento Individual definition. Additionally, as previously noted, concerns exist about HMIS’s ability to accurately record family status. HUD, HHS, and Education also report on other populations experiencing homelessness. HUD estimated that over the course of 2008, unaccompanied youths accounted for 2 percent of the sheltered homeless population, or approximately 22,000 unaccompanied youth who were homeless and sheltered. According to HHS, over the course of fiscal year 2008, approximately 48,000 youths experienced homelessness and received services from HHS’ Basic Center Program or Transitional Living Program, which have different eligibility criteria from HUD’s programs. Some youths may be in shelters funded by both HHS and HUD, and therefore be counted in both HMIS and RHYMIS, while others might be in shelters funded only by HUD or only by HHS and only included in the corresponding database. As shown in figure 2, Education reported that more than 770,000 homeless children received services in the 2007–2008 school year, but less than one quarter of these children—about 165,000—were living in shelters. HUD reported for that same year that approximately 150,000 children aged 6 to 17 were in shelters. Federally-funded mainstream programs, whose primary purpose is to provide a range of services and funds to low-income households, often provide these services and funds to those who are experiencing or have experienced homelessness or to those defined as being at risk of becoming homeless. Thus, while homelessness is not the primary focus of these programs, data collected by them could be useful for understanding the nature of homelessness. Further, several researchers and advocates with whom we spoke noted that they could better understand the dynamics of homelessness if these programs collected individual client-level data on homelessness and housing status as part of their routine data collection activities. However, these programs have not consistently collected data on homelessness and housing status. A few programs have collected individual data, some have collected aggregate data, and others collect no data on housing status at all. We identified several federally-funded mainstream programs that collect or are beginning to collect and report client-level data on persons experiencing homelessness to the federal agency overseeing the mainstream program. Public Housing Authorities (PHA) collect data on homelessness status of households at the time the PHA admits the household to a housing assistance program, which includes both Public Housing and Housing Choice Voucher programs; they report these data to HUD’s Office of Public and Indian Housing. HHS’s Substance Abuse Prevention and Treatment Block Grant program requires grantees to report participants’ living arrangements at entry and exit. DOL’s WIA Adult and Youth grantees also collect and report individual-level data on enrolled participants including whether the client is homeless. HHS’s John H. Chafee Foster Care Independence Program has developed a survey that states must begin using by October 2010 to gather data for the National Youth in Transition Database—a data collection required by the Foster Care Independence Act of 1999. States are required to survey foster care youths at ages 17, 19, and 21 to collect data on the services provided to, and outcomes of, youths in the foster care system. The survey includes a question asking youths if they have experienced homelessness over the relevant time period; however, as previously noted, the social stigma attached to the word homeless often limits self-identification. States administer USDA’s SNAP program, document if a person or family is homeless, and report a sample of data to USDA, which uses the data to assess the accuracy of eligibility decisions and benefit calculations. A number of other programs require that grantees report aggregate data to their funding agency on the number of persons experiencing homelessness that they served: Head Start grantees report the number of homeless families served annually to HHS. Health Center Program grantees collect limited data on the homelessness status of program participants and report the total number of participants known to be homeless to HHS. Community Mental Health Services Block Grant grantees collect and submit data to HHS on persons served by the program, including “homeless or shelter.” The Ryan White HIV/AIDS Program collects and reports to HHS limited aggregate data on the living arrangements (permanent, homeless, transient, or transitionally housed) of clients served. HHS has numerous other mainstream programs that provide funds to states to provide services to certain low-income populations, including those experiencing homelessness, but data collection and reporting on homelessness or housing status varies by program and across states. Medicaid and TANF are the two largest programs, but states are not required to collect or submit information to HHS on the number of individuals or families experiencing homelessness that they served. States determine eligibility requirements and develop program applications for TANF and Medicaid. A recent HHS study that surveyed all the states found that all states collected minimum housing status data on their Medicaid and TANF applications, such as home address and if the applicant resides in public or subsidized housing, a long-term care facility, or a medical or rehabilitation facility. Twenty eight states collected indicators of homelessness—such as whether an individual resides in a shelter, stays in a domestic violence shelter, or has a permanent home—on their applications. Thirteen states collected information on risk factors often associated with homelessness—such as whether an individual lives with friends or relatives, or has an eviction notice—on their applications. However, these states did not collect this information using consistent definitions and used the data in limited ways. According to the HHS report, most states responding to HHS’s survey said that they did not know whether they had procedures in place to improve the quality of the items collected and thus how complete their homelessness data were. Additionally, while data on homelessness indicators and risk factors resided in statewide databases in many states, the data were not routinely confirmed or verified, making it unclear how reliable the data might be for analysis of homelessness. Further, as previously discussed, homelessness status changes over time, and data collected at one point in time may not accurately capture these changes. Nonetheless, in Michigan, New York City, and Philadelphia, researchers and state officials have been able to use identifying data in mainstream databases to match data in HMIS, and have thus been able to identify patterns in mainstream service usage for homeless populations. Several other mainstream programs provide services for persons experiencing homelessness, but do not provide aggregate or individual- level data on homeless clients served. The Community Services Block Grant, Social Services Block Grant, Maternal and Child Health Block Grant, and the Children’s Health Insurance Program all provide HHS with regular program reports. However, these reports do not include data on the number of clients experiencing homelessness or other housing status data. Although child welfare agencies often collect data on housing status and stability in the process of reviewing family reunification cases, this information is not reported to HHS. Community Development Block Grants often fund services that may benefit those experiencing homelessness, but grantees do not track the number of homeless served by the program. Additionally, local PHAs can give preferences to individuals and families experiencing homelessness; however, PHAs do not have to submit data on these preferences to HUD. HUD sampled Public Housing and Housing Choice Voucher Program to determine how many of them have a preference for those experiencing homelessness. The analysis showed that in 2009, approximately 27 percent of all PHAs had a homeless preference. Finally, agencies have not always consistently collected or analyzed data on housing stability or homelessness because these are not the primary purposes of their programs. In addition, data collection may be expensive, and agencies must weigh the costs and benefits of getting more detailed information. Collecting data on homelessness or housing status for programs such as TANF and Medicaid could be further complicated by the need to work with 50 different state offices to implement a new data collection effort. However, HHS recently reported that of the 28 states that do collect homelessness data, almost all of them indicated that it is not burdensome or costly to collect such data, and about half of the states that collect data said they would comply with requests to make some homelessness data available to HHS for research purposes. Yet even among the willing states, there were some concerns about resource constraints for responding to such requests and concerns about the reliability of the data. However, not having complete and accurate data limits the understanding of the nature of homelessness—a better understanding of which could be used to inform programs and policies designed to improve housing stability and thus reduce homelessness. The 45 research studies analyzing factors associated with homelessness that we reviewed used different definitions or measurements of homelessness, although many of the studies used definitions or measures that were more closely affiliated with the McKinney-Vento Individual definition than with the broader McKinney-Vento Children and Youth definition (see appendix II for a list of the 45 studies). As a result, study findings are difficult to compile or compare. In the absence of a consistent definition and measurement, “homelessness” can mean or designate many conditions. For example, homelessness can refer to long-term homelessness, short stays in shelters, living in nontraditional housing, or living with relatives, friends, or acquaintances. These definitional differences especially limited research on some specific populations, such as “runaway or homeless” youths. The research we reviewed also varied in how it defined and measured the factors that may be associated with the likelihood of experiencing homelessness. For instance, studies that examined families and youths used different definitions or, in some cases, failed to clearly define what they meant by families and youth. Several studies measured variables such as marital status, social or family support, or domestic violence differently. For example, in assessing relationships between family structure and homelessness, one study examined whether a father of a child was cohabitating with a woman, while another study looked at whether the individual was presently married, although it is possible the two categories overlapped. Studies also used various age categories to define youths, including under 17, from 14 to 23, or from 12 to 22. In addition, some studies did not consider factors that figured prominently in other studies, such as the economic conditions of the surrounding area or how childhood experiences influenced later episodes of homelessness. To contribute to a broad-based and reliable understanding of what factors are associated with the likelihood of experiencing homelessness, studies we reviewed and experts with whom we spoke noted research would need to use data that accurately reflect the population studied, track the same individuals or families over time, and consider a broad population over diverse locations. Further, such studies would need to consider a range of both structural factors, such as area poverty level, and individual factors, such as a person’s age. However, the majority of the studies we reviewed did not meet these criteria. As a result, the body of literature we reviewed cannot be used to predict with accuracy who among those at risk of homelessness would likely experience it. Studies we reviewed used samples from several types of data, such as providers’ administrative databases or surveys, but were not always able to ensure that data accurately reflected the population they studied. Approximately half of the studies used information from administrative records or other service-oriented data, such as standardized self- assessments. The remaining studies used information collected in interviews, surveys, or questionnaires. Studies using administrative data may be especially vulnerable to biased sampling or undercounting of street homeless populations because of the myriad issues described previously, such as collecting data only on those receiving services. Some researchers noted that data from secondary sources such as administrative data may be less accurate than data collected by research staff and targeted for research purposes. However, survey data collected for research purposes also are subject to undercounting and biased sampling, because populations experiencing homelessness are difficult to reach. Because people move in and out of homelessness and experience it for different periods, studies we reviewed and experts with whom we spoke noted that data would need to be collected on the same individuals or families over time to more clearly identify which factors could lead to an episode of homelessness or help determine homelessness experiences over longer periods. Like HUD’s point-in-time homeless counts, these studies more likely captured those individuals or families who had been homeless for long periods as opposed to those who experienced it episodically or for short periods, and thus do not give a clear understanding of factors associated with homelessness. These studies also could not determine whether factors associated with being homeless at a point in time caused homelessness. For example, one study found an association between poor physical health and homelessness, but could not say whether poor physical health contributed to experiencing homelessness or whether homelessness contributed to or worsened physical health. Nineteen studies in our review used data that did follow individuals or families over time. However, several of these used administrative data that suffered from the shortcomings described previously, followed individuals or families for relatively short periods, or considered populations in narrow geographic locations. A few studies also used national databases such as the Fragile Families and Child Wellbeing Study and one used the 1997 National Longitudinal Survey of Youth that annually tracks a sample of youth and their parents over time. In addition, most of the studies we reviewed defined their target populations—or the group of people to whom findings can be generalized—narrowly, making it difficult to generalize results to broader populations or to compare or compile them. Much of the research we reviewed focused on small subsets of the population experiencing homelessness in smaller geographic regions, such as those with mental illness or substance abuse problems in a single shelter or city. For example, one study published in a journal on Community Mental Health focused on African Americans admitted to a state psychiatric hospital in New York, and another study published in a journal on youth and adolescence looked at youths aged 14 to 21 years who needed the services of a homeless drop-in center. In part, the target groups studied reflected the wide variety of disciplines—psychology, public policy, public health, and economics—of those conducting the studies. Although researchers have argued that it is necessary to consider structural or macro-level factors (such as employment rate, surrounding poverty level, and availability of affordable housing) as well as individual- level factors to arrive at a full understanding of which factors are associated with the likelihood of experiencing homelessness, only about one-third of the studies we reviewed considered these factors. Structural factors help to explain the prevalence of homelessness across a wider setting, while individual-level factors may explain the immediate circumstances surrounding an episode of homelessness. In addition, over three quarters of the service providers, researchers, advocates, and government agency officials we interviewed identified a structural factor—the lack of affordable housing—as a major barrier to serving those experiencing homelessness. However, most of the studies did not look at structural factors and focused on individual-level factors such as demographic characteristics, individual income, the presence of a mental illness, or substance abuse. Because the majority of the studies that we reviewed examined populations in one or a few cities, it was not possible for them to examine the role played by structural factors, such as unemployment rates and surrounding poverty levels, in a wider context. Although limitations in the studies we reviewed posed challenges for drawing comparisons and often focused on narrow populations in smaller areas, we identified two that tracked homeless families over time and considered structural and individual-level factors across wide geographical areas. One study that defined homelessness as living in a shelter, on the street, or in an abandoned building or automobile, but also considered the population that was doubled up, examined factors associated with individual and family homelessness using nationwide data from the Fragile Families and Child Wellbeing database, which was collected over several years. The study analyzed data on mothers when their children were one and three years old. One hundred and twenty-eight mothers reported experiencing homelessness at the one-year birthday, while 97 reported being homeless when their child turned three. A larger number of mothers reported being doubled up—343 at their child’s one-year birthday and 223 when their child turned three. The study found that the availability of affordable housing—a structural factor—reduced the odds of families experiencing homelessness and doubling up. A number of individual-level factors were associated with experiencing homelessness or doubling up. Specifically, access to small loans and childcare, having a strong family and friend support network, and living longer in a given neighborhood were associated with lowered odds of experiencing homelessness. Additionally, receiving public assistance reduced the likelihood that someone would live doubled up. Another study considered families homeless if they were living on the street, in temporary housing, or in a group home, or had spent at least one night in a shelter or other place not meant for regular housing in the past 12 months. This study, which used the Fragile Families and Child Wellbeing database found that families with higher incomes who received housing assistance had a reduced likelihood of experiencing homelessness. Physical and mental health problems, reports of domestic violence, and substance abuse issues appeared to place them at greater risk for homelessness. Receipt of TANF and poorer surrounding economic conditions—a structural factor—also were positively related to the likelihood of experiencing homelessness but, according to the authors, likely were proxies for individual need and lack of income rather than directly associated with homelessness. Two other studies looked at the association of structural factors and rates of homelessness across geographical areas over time, but did not track specific individuals or families: One nationwide study that tracked homelessness rates over time primarily examined how structural factors affected rates of homelessness. The study found that relatively small changes in housing market conditions could have substantial effects upon rates of homelessness or the numbers of persons in shelters. Their results imply that relatively small increases in housing vacancy rates, combined with small decreases in market rents, could substantially reduce homelessness. Another study that focused on the impact of structural factors on homelessness in 52 metropolitan areas found that poverty levels strongly related to the number of persons experiencing homelessness in an area. No other structural factors—such as unemployment rates, the number of government benefit recipients, or availability of affordable housing in the area—were found to be statistically significant predictors of homelessness. Together, the four studies underlined the importance of structural factors and identified some individual factors associated with homelessness; however, they did not address some issues of importance. None addressed the extent to which childhood experiences were associated with adult homelessness, and only one examined those living in doubled up situations. We reviewed 11 other studies that examined how childhood experiences were associated with experiencing homelessness in adulthood; however, these studies generally relied on people’s recollections. While the studies used varying methodologies and definitions of homelessness and other factors, most highlighted the influence of early childhood experiences on the likelihood of later experiencing homelessness. Results varied by study, but several studies found that factors such as running away from home, being in foster care, having a dysfunctional family, or being sexually molested as a child increased the odds an adult would experience homelessness. Similarly in 1996, the National Survey of Homeless Assistance Providers and Clients found that homeless adults reported many significant adverse childhood experiences. That survey did not compare those experiencing homelessness with those that were not. However, the findings from the studies we reviewed that did compare the two groups generally were consistent with the survey’s findings. Conversely, another study found that a range of childhood experiences (including residential stability: adequacy of income; dependence on public assistance; family violence; and parental criminality, mental illness, or substance abuse) were not significantly associated with adult homelessness. Recognizing that the relationships between living doubled up or in shelters or on the street are important to understanding homelessness, we identified a few studies that analyzed whether doubling up could predict future time spent in a shelter or on the street, or that measured differences at a point in time between those living doubled up and those living in shelters or on the street. However, the results of the studies were inconclusive. Of the two that examined how doubling up affects later homelessness in a shelter or on the street, one found that it was significant and the other found it was not significant. Of the four studies that compared persons on the street or in a shelter with those doubled up, two found few differences in demographic characteristics or backgrounds. A third found some differences between the two groups. For example, receiving public assistance lowered the chance of doubling up but was not significantly associated with homelessness. The fourth study found significant differences between doubled up and homeless mothers. Doubled up mothers were more likely to be younger and working and to have high school degrees, fewer children, and more relatives who could help with finances, housing, and child care. Among the majority of the advocates, government officials, service providers, and researchers we interviewed that identified differences in definitions of homelessness as an important barrier to providing services, several noted that families and youths living in some precarious situations were not eligible for federal assistance under a narrow definition of homelessness. Some said that families and youths who were doubled up or living in hotels because of economic hardship often had similar or greater needs for services than those who met narrower definitions, but were being excluded from receiving government-funded services. For example, those working in educational programs that have broader federal definitions of homelessness noted that those who do not meet the narrow definition have difficulty accessing housing services. One of the school liaisons we visited described visiting a house with a caved-in floor and no front door. This family met the criteria of substandard housing under the McKinney-Vento Children and Youth definition of homelessness, but it is unclear whether the house would have been considered abandoned or condemned, and if the family would have qualified as homeless under the narrower individual definition prior to the HEARTH Act. According to a research study presented at the HUD-HHS homelessness research symposium in 2007, a formal condemnation process for substandard properties does not typically exist in rural areas, and, as a result, properties that would meet the HUD definition of abandoned because they have been condemned in urban areas may not meet that definition in rural areas. HHS provides grants for Head Start programs to collaborate with others in the community to provide services for children and their families; however, officials noted that in the 2009 program year, less than half of the families in Head Start who experienced homelessness acquired housing. HHS has attributed this to a lack of affordable housing and long waiting lists for housing assistance. However, officials for at least one service provider said that the waiting list for housing assistance in their city was much longer for those that do not meet the narrow definition of homelessness. Many of those involved in homeless programs with whom we spoke were particularly concerned about the exclusion of families and youths from programs that addressed the needs of chronically homeless individuals— those unaccompanied individuals who have disabilities and have been continuously homeless for a year or homeless four times in the last 3 years. Before the passage of the HEARTH Act, families that otherwise met the criteria for chronic homelessness programs were not able to participate because chronic homelessness was defined to include only unaccompanied individuals. People in all of the categories we interviewed noted that the emphasis on funding programs for chronic homelessness has meant that families have been underserved. A youth service provider further noted that youths effectively were excluded from programs for those experiencing chronic homelessness because youths generally did not live in shelters or keep records of where they had been living or for how long. Those that cited differences in definitions as a barrier said that families and youths with severe shelter needs had to be on the street or in shelters to access some federally-funded homeless assistance, but shelters were not always available or appropriate for them. Researchers we interviewed noted that families have to obey a number of rules to stay in a shelter and families with the greatest challenges might be less able to follow those rules. Additionally, some facilities do not provide shelter for males above a certain age, so that couples or families with male teenage children may not be able to find shelter together. Similarly for youths, a researcher and a service provider suggested that adult shelters were not appropriate for unaccompanied youths or young adults, and shelters specifically for them were very limited. Some of the people we interviewed also noted that some narrow definitions of homelessness limited services that could be provided to individuals experiencing homelessness. For example, getting one service sometimes precluded individuals from getting another service for which they would otherwise have qualified. Officials at DOL told us that if veterans obtain housing vouchers through HUD-VASH, they no longer meet the narrow statutory definition of homelessness under which they would be eligible for job training funded by the Homeless Veterans Reintegration Program (HVRP). However, if veterans first apply for HVRP and then for vouchers, they can qualify for both programs. Similarly, those in transitional housing programs cannot be considered eligible for programs serving those experiencing chronic homelessness even if they meet the other requirements, such as being homeless for a year and having a disability. In addition, although HUD has recognized in its documents that helping people make successful transitions to the community as they are released from foster care, jails, prisons, and health care, mental health, or substance abuse treatment facilities requires systems to work together to ensure continuity of care and linkages to appropriate housing and community treatment and supports, the definitions of homelessness may hinder these transitions. In August 2009, one advocate noted that HUD’s definition of homelessness includes those that spend 30 days or less in prison if they had been homeless prior to entering prison, but those spending more than 30 days cannot be considered homeless until the week before their release. The advocate said that this limits the incentive for prison staff to work with homeless service providers to allow for a smooth transition from prison to housing and that if an individual leaving prison spends time on the street or in an emergency shelter, the likelihood of recidivism increases. Some of those arguing for a broader definition also have said that the definition of homelessness should not depend on available funding. Officials at one large service provider said that broadening the definition would not necessarily spread a fixed amount of resources across a larger group. Instead, targeting resources to specialized populations more effectively and concentrating on earlier intervention and prevention could lower the cost of serving individual clients. However, they also noted that this might require a better understanding of the needs of particular subgroups experiencing homelessness. Some local officials, homeless service providers, and researchers noted that choosing between a narrow or a broad definition of homelessness was less important than agreeing on a single definition, because multiple definitions made it more difficult or costly to provide services and created confusion that sometimes led to services not being provided to those legally eligible for them. Many researchers, government officials, and advocates with whom we spoke noted the importance of combining services and housing to meet the needs of those experiencing homelessness, and some of these noted that this was more difficult and costly when programs defined homelessness differently. They also noted that obtaining funding for services from sources other than HUD has become more necessary because the proportion of HUD funding for services has declined. Officials at HUD noted that this was a result of HUD having provided incentives to communities to increase the ratio of housing activities to supportive service activities in their funding applications to encourage the development of more housing resources for individuals and families experiencing homelessness. Not only do some targeted programs that provide services use different definitions of homeless, but some state and local grantees receiving federal funds under mainstream programs that can be used to provide certain services for those experiencing homelessness (such as TANF) develop their own local definitions of homelessness. Officials at a lead Continuum agency said that having these different definitions makes putting together funding for permanent supportive housing—the best solution for ending chronic homelessness—especially difficult. Officials at two entities that provide service to and advocate for those experiencing homelessness noted that, given the multiple definitions, scarce resources that could have been used to provide services instead went to eligibility verification. Furthermore, many of those involved in activities related to homelessness said that having multiple definitions created confusion, and government officials overseeing programs that use a broader definition and a service provider in one of these programs noted that this confusion could lead to services not being provided to those that are eligible for them. A school liaison and a youth service provider said that school administrative personnel often apply a narrower definition of homelessness than McKinney-Vento Children and Youth and thus may deny students access to services to which they are entitled. Additionally, Education has cited a state education agency for the failure of local education agencies’ to identify, report, and serve eligible homeless children and youths including youths in doubled-up situations that meet the broader definition of homelessness. Similarly, officials at HHS acknowledged that Head Start programs across the country sometimes were not using the appropriate definition of homelessness to identify children who qualified for those services. As a result, some homeless families would not be receiving Head Start services. However, some government officials, researchers, advocates, and service providers thought that having multiple or narrow definitions of homelessness had certain benefits. Some HHS officials in programs that address homelessness and others noted that having multiple definitions of homelessness allowed programs to tailor services and prioritize them for specific populations. HUD officials and some researchers and advocates said that having a narrow definition for homeless programs that provide shelter for specific populations and broader definitions for programs such as those designed to serve the educational needs of children and youths allowed programs to meet their goals best. HUD officials noted that having a broader definition for certain education programs is appropriate because those that meet the definition are entitled to the service, and the program does not provide housing. Alternatively, it is appropriate for programs such as HUD’s to have a narrower definition because its services are not entitlements and must target those most in need, such as those that are chronically homeless. HUD, HHS, VA, and DOL began redirecting resources to this narrowly defined group in 2003, and according to HUD point-in-time data, chronic homelessness fell by approximately 27 percent from the January 2005 count to the January 2008 count. HUD, HHS, and VA focused on this group, in part, because a research study had shown that they used an inordinate amount of shelter resources. One researcher noted that having a precise definition was essential to ensure that the same kinds of people are being counted as homeless in different locations, which would be important for measuring program outcomes. Supporters of a narrow definition also said that if the definition were broadened, limited resources might go to those who were easier to serve or had fewer needs, specifically to those families with young children who were doubled up rather than to those identified as chronically homeless. Finally, some advocates for those experiencing homelessness and government officials overseeing programs targeted at those experiencing homelessness noted that if the definition of homelessness were broadened for some programs without an increase in resources, many of those that would become eligible for services would not get them. In the HEARTH Act, Congress provided a broader definition of homelessness for those programs that had been serving individuals and families and using the McKinney-Vento Individual definition; however, it is still not as broad as the McKinney-Vento Children and Youth definition, so different definitions will still exist when the HEARTH Act is implemented. In addition, the HEARTH Act mandated that the Interagency Council convene experts for a one-time meeting to discuss the need for a single federal definition of homelessness within 6 months of the issuance of this report. However, having one definition of homelessness would not necessarily mean that everyone who met that definition would be eligible for all homeless assistance programs or that those not defined as homeless would be ineligible. Some of the people we interviewed suggested alternatives—one based on a narrow definition of homelessness and others based on a broader definition. For example, one local official suggested defining homelessness using the narrow McKinney-Vento Individual definition and defining another category called “temporarily housed” that would include those who are doubled up or in hotels. While some programs might only be open to those experiencing homelessness, others such as the Education of Homeless Children and Youth program could be open to both groups. Alternatively, one researcher directed us to a classification scheme developed by the European Federation of National Associations Working with the Homeless. Under that classification scheme, homelessness was defined broadly as not having a suitable home or one to which a person was legally entitled, but then a typology was created that defined subcategories of living situations under headings such as “roofless” or “inadequate” that could be addressed by various policies. Officials at a large service provider we interviewed made similar distinctions saying that it is best to think of people as experiencing functional homelessness—that is, living in situations that could not be equated to having a home—rather than to think of them as literally homeless or doubled up. However, these officials said that subcategories of need would have to be developed based on a better understanding of homelessness, because all persons experiencing homelessness should not be eligible for the same services. In 2007, HHS convened a symposium to begin discussing the development of a typology of homeless families, and in May 2010, they convened about 75 federal and nonfederal participants to discuss issues related to children experiencing homelessness. The lack of affordable housing (whether housing was not available or people’s incomes were not high enough to pay for existing housing) was the only barrier to serving those experiencing homelessness cited more frequently by researchers, advocates, service providers, and government officials we interviewed than definitional differences. Some researchers have shown that more housing vouchers could help eradicate homelessness, but a research study also has shown that generally federal housing subsidies are not targeted to those likely to experience homelessness. Those with certain criminal records or substance abuse histories may not be eligible for federal housing assistance, and these factors sometimes are associated with homelessness. Although certain federal programs target vouchers to those who are most difficult to house, local service providers may still refuse to serve those who have been incarcerated or have substance abuse problems. For example, while the HUD-VASH program is to be available to many of these subpopulations, HUD officials and others told us that local service providers still refuse to serve them. In addition, while HUD estimates that 27 percent of PHAs have preferences for those experiencing homelessness, many of them restrict these programs to those who may be easier to serve. Service providers, advocates, researchers, and government officials that we interviewed also cited eligibility criteria for mainstream programs as a main barrier to serving those experiencing homelessness. In 2000, we reported on barriers those experiencing homelessness faced in accessing mainstream programs, and this is a continuing issue. To obtain benefits, applicants need identification and other documents, which those experiencing homelessness often do not have. Without documentation, they sometimes cannot enter federal and state buildings where they would need to go to get documentation or obtain benefits. Those that cited access as a barrier particularly noted difficulties with SSI/SSDI programs. Service providers and government officials noted that those experiencing homelessness may not receive notices about hearing dates or other program requirements because they lack a fixed address. At least one researcher told us that an initiative, SSI/SSDI Outreach, Access and Recovery (SOAR), has improved performance. The initiative’s Web site says that those experiencing homelessness normally have a 10–15 percent chance of receiving benefits from an initial application, but that SOAR has increased success to 70 percent in areas it serves. However, one local agency in an area served by SOAR told us in January 2010 that most applicants were rejected initially. Some of those we interviewed also noted that Medicaid applicants have some similar problems. For example, one advocate noted that it is difficult for those experiencing homelessness to get through the application process and, when necessary, prove disability; however, because Medicaid is a state- run program, these problems are worse in some states than in others. Another provider noted that Medicaid requires that information be periodically updated, and those experiencing homelessness may not receive notices of this. As a result, they may lose their benefits and be required to travel a long distance to get them reinstated. Finally, service providers said that PHAs often restrict federal housing assistance to those without substance abuse issues or certain criminal records and that programs generally have long waiting lists. Because homelessness is a multifaceted issue and a variety of programs across a number of departments and agencies have been designed to address it, collaborative activities are essential to reducing homelessness in a cost-effective manner. In prior work, we have determined that certain key activities, such as setting common goals, communicating frequently, and developing compatible standards, policies, procedures, and data systems, characterize effective interagency collaboration. In addition, we found that trust is an important factor for achieving effective collaboration. Efforts to address homelessness often have stressed the need for local, communitywide collaboration. For instance, entities applying to HUD for Homeless Assistance Grants have to come together as a Continuum to file applications. Other agencies or individuals, such as the school systems’ homeless liaisons, also are required to coordinate activities in the community. In addition, from 2002 to 2009, Interagency Council staff encouraged government officials, private industry, and service providers to develop 10-year plans to end homelessness or chronic homelessness and provided tools to communities to assist with the development of these plans. Many communities have developed these plans, but whether plans have been implemented or have been achieving their goals is unclear. The Interagency Council reports that 332 of these plans have been drafted. All of the locations we visited had drafted plans at the state or local level, however, in two of the four sites—California and South Carolina—plans that had been drafted had not been adopted by appropriate local or state government entities and thus had not been implemented. Some of the people with whom we spoke said that differences in definitions of homelessness limited their ability to collaborate effectively or strategically across communities. Local officials or researchers in three of the four locations we visited noted that certain elements of collaboration were difficult to achieve with different definitions of homelessness. In one location we visited, local agency officials who had extensive experience with a broad range of homelessness programs and issues noted that multiple definitions impeded those involved in homelessness activities from defining or measuring a common problem and were a major obstacle to developing measures to assess progress in solving the problem. Further, they noted that the trust of the local community in officials’ ability to understand the problem of homelessness was eroded when recent point-in-time counts showed that numbers of families experiencing homelessness under one definition declined while the number of families receiving homeless services in other programs that defined homelessness more broadly increased. In two other locations, local government officials and a researcher involved in evaluating local programs said that having multiple definitions of homelessness impeded their ability to plan systematically or strategically for housing needs or efforts to end homelessness at the community level. Congress also recognized the importance of federal interagency collaboration when it authorized the Interagency Council in the original McKinney-Vento Act and reauthorized it in the HEARTH Act. Some of the people we interviewed further noted that collaboration among federal programs was essential because addressing homelessness required that those in need receive a holistic package of services that might encompass the expertise and programs of a number of agencies. They also said that collaboration was necessary to prevent people from falling through gaps created by certain events, such as entering or leaving hospitals or prisons, aging out of foster care or youth programs, or otherwise experiencing changes in family composition. Further, they noted that, with HUD’s emphasizing housing rather than services in its funding priorities, the need for effective collaboration was greater now than in the past. Finally, officials at HUD, HHS, and Education noted that at a time of budget austerity collaboration among agencies was an effective way to leverage scarce resources. While we noted in 1999 and again in 2002 that homeless programs could benefit from greater interagency coordination, many of the government officials, researchers, advocates, and service providers we interviewed who were knowledgeable about multiple federal agencies said that collaboration among federal programs and agencies had been limited or did not exist at all. Generally, those we interviewed in our current work said that, from 2002-2009, the Interagency Council had focused on that part of its mission that required it to foster local collaboration rather than on that part that required it to foster collaboration among federal agencies. In addition, some of those we interviewed said that federal program staff had focused largely on their own requirements and funding streams rather than on collaborative approaches to addressing homelessness. In 1994, the Interagency Council issued an interagency plan to address homelessness that called for federal agencies to streamline and consolidate programs, when appropriate, and introduced the concept of a Continuum of Care, but did not include any longer-term mechanism to promote interagency collaboration, such as joint funding of programs. Following issuance of this plan, the Interagency Council did not again receive funding until 2001, although it did undertake some joint activities including coordinating and funding a survey of service providers and persons experiencing homelessness. In 2002, an executive director was appointed and, according to some of those involved with the Interagency Council, the council turned its attention largely to helping communities draw up 10-year plans to end chronic homelessness. In the HEARTH Act, Congress called on the Interagency Council to develop a strategic plan to end homelessness that would be updated annually, and in November 2009, a new executive director took office. In preparation for the strategic plan and in response to new staffing and funding at the Interagency Council and elsewhere, agencies and the Council appear more focused on interagency coordination. The Interagency Council issued its strategic plan on June 22, 2010. The plan says that it is designed to neither embrace nor negate any definition of homelessness being used by a program. Federal agencies have also not collaborated effectively outside the Interagency Council. Those we interviewed noted that agencies have focused on their own funding streams and have not coordinated dates for applying for grants that could be combined to provide housing and services for those experiencing homelessness. Service providers must apply for grants at different times, and grants run for different periods and have different probabilities of being continued. A provider might receive funding to build permanent housing but might not receive funding needed for certain support services, or vice versa. One group knowledgeable about an array of housing programs said that recently an HHS grant tried to link its funding to HUD’s, but a lack of full collaboration between the agencies created confusion and discouraged some service providers from applying for the HHS grant. The HHS grant required that applicants have an executed grant from HUD when they applied for the HHS grant. However, HHS applications were due before HUD had executed any of its grants. HHS officials then relaxed their grant criteria, saying that they would evaluate the lack of an executed grant contract with HUD on a case- by-case basis. HUD officials said that the grant criteria were relaxed to include recognition of HUD’s conditional grant award letters. Two groups with whom we spoke also noted that funding from multiple agencies often focused on demonstration projects and that grant processes for these also were not well coordinated and funding ended abruptly. Officials at HUD noted that lack of coordination on grants across agencies is likely the result of the statutes that authorize programs and agency regulations that implement them. Some of the service providers, advocates, and government officials we interviewed cited specific examples of successful programmatic collaboration, such as the HUD-VASH program, and federal agency officials directed us to a number of initiatives that illustrate a greater emphasis on interagency collaboration. HUD officials noted that they have been partnering with HHS and VA to improve and align their data collection and reporting requirements for federally-funded programs addressing homelessness. For example, HUD and HHS announced in December 2009 plans to move toward requiring that HHS’s PATH program use HMIS for data collection and reporting for street outreach programs. They noted that the agencies had agreed to align reporting requirements by establishing common outputs and performance outcomes. The plan called for HHS to begin providing technical assistance and training activities for PATH programs on individual-level data collection and reporting and alignment with HMIS in 2010, and to seek approval for a revised annual report to include HMIS data in 2011. In February 2010, officials from HUD, HHS, and Education—key agencies for addressing homelessness for nonveterans—outlined proposals on homelessness included in the proposed FY 2011 budget. These included a demonstration program that combines 4,000 HUD housing vouchers with HHS supportive services and another program that calls for HUD, HHS, and Education to be more fully engaged in stabilizing families. The latter proposal calls for HUD to provide 6,000 housing vouchers on a competitive basis. We also found that federal agency staff did not effectively collaborate within their agencies. For example, in January 2010, staff at one of HUD’s field offices told us that while collaboration between those involved in the Homeless programs and those involved in Public Housing programs would be beneficial, any coordination between these two HUD programs was “haphazard.” In February 2010, the Assistant Secretaries for the Offices of Public and Indian Housing and Community Planning and Development, which includes homeless programs, reported that they are meeting weekly and looking for ways to better coordinate programs. In another example, staff at HHS who developed the National Youth in Transition Database, which includes looking at experiences with homelessness, had not consulted with staff in the Family and Youth Services Bureau, who administer the Runaway and Homeless Youth Programs and generally were recognized as having some expertise on youths experiencing homelessness. Finally, we observed that while coordination has been limited, it was more likely to occur between those parts of agencies that were using a common vocabulary. For example, state McKinney-Vento education coordinators and local education liaisons are required to coordinate with housing officials and providers in a number of ways; however, the McKinney-Vento Homeless Education Program coordinator in one of the states we visited said that while she has coordinated locally with staff from Head Start, an HHS program that also uses the McKinney-Vento Children and Youth definition of homelessness, she has found it very hard to coordinate with local HUD staff that use a different definition of homelessness, because they did not see how the education activities relate to their programs. In addition, those agencies that have agreed on a definition of chronic homelessness—HUD, HHS, DOL, and VA—have engaged in some coordinated efforts to address the needs of those that met the definition. For many years, the federal government has attempted to determine the extent and nature of homelessness. As part of this effort, Education, HHS, and HUD have systems in place that require service providers involved in the homelessness programs they administer to collect data on those experiencing homelessness and report these data in various ways to the agencies. However, while the data currently being collected and reported can provide some useful information on those experiencing homelessness, because of difficulties in counting this transient population and changes in methodologies over time, they are not adequate for fully understanding the extent and nature of homelessness. In addition, the data do not track family composition well or contribute to an understanding of how family formation and dissolution relate to homelessness. Further, because of serious shortcomings and methodologies that change over time, the biennial point-in-time counts have not adequately tracked changes in homelessness over time. While these data systems have improved, it still is difficult for agencies to use them to understand the full extent and nature of homelessness, and addressing their shortcomings could be costly. For example, one shortcoming of HUD’s point-in-time count is that it relies on volunteer enumerators who may lack experience with the population, but training and utilizing professionals would be very costly. In part because of data limitations, researchers have collected data on narrowly defined samples that may not be useful for understanding homelessness more generally or do not often consider structural factors, such as area poverty rates, which may be important in explaining the prevalence and causes of homelessness. In addition, because complete and accurate data that track individuals and families over time do not exist, researchers generally have not been able to explain why certain people experience homelessness and others do not, and why some are homeless for a single, short period and others have multiple episodes of homelessness or remain homeless for a long time. However, those who have experienced or might experience homelessness frequently come in contact with mainstream programs that are collecting data about the recipients of their services. While homelessness is not the primary focus of these programs, if they routinely collected more detailed and accurate data on housing status, agencies and service providers could better assess the needs of program recipients and could use these data to help improve the government’s understanding of the extent and nature of homelessness. Researchers also could potentially use these data to better define the factors associated with becoming homeless or to better understand the path of homelessness over time. Collecting these data in existing or new systems might not be easy, and agencies would incur costs in developing questions and providing incentives for accurate data to be collected. Collecting such data may be easier for those programs that already collect some housing data on individuals, families, and youths who use the programs and report those data on an individual or aggregate basis to a federal agency, such as HHS’s Substance Abuse Treatment and Prevention Block Grant program or Head Start. For those mainstream programs that do not currently report such data, collecting it may be a state or local responsibility, and the willingness of states to collect the data may vary across locations. For example, HHS has reported that about half of the states that do collect homelessness data do not consider it burdensome to do so through their TANF and Medicaid applications, and would be willing to provide data extracts to HHS for research purposes. States or localities and researchers could find these data useful even if they are not collected on a federal or national level. However, concerns exist about resource constraints and data reliability. Therefore, the benefits of collecting data on housing status for various programs would need to be weighed against the costs. Federal efforts to determine the extent and nature of homelessness and develop effective programs to address homelessness have been hindered by the lack of a common vocabulary. For programs to collect additional data on housing status or homelessness or make the best use of that data to better understand the nature of homelessness, agencies would need to agree on a common vocabulary and terminology for these data. Not only would this common vocabulary allow agencies to collect consistent data that agencies or researchers could compile to better understand the nature of homelessness, it also would allow agencies to communicate and collaborate more effectively. As identified in 2011 budget proposals, Education, HHS, and HUD are the key agencies that would need to collaborate to address homelessness, but other agencies that also belong to the Interagency Council—a venue for federal collaborative efforts— such as DOL and DOJ might need to be involved as well. However, agency staff may find it difficult to communicate at a federal or local level when they have been using the same terms to mean different things. For example, agencies might want to avoid using the term homelessness itself because of its multiple meanings or the stigma attached to it. Instead, they might want to list a set of housing situations explicitly. The agencies could begin to consider this as part of the proceedings Congress has mandated that the Interagency Council convene after this report is issued. Once agencies have developed a common vocabulary, they might be able to develop a common understanding of how to target services to those who are most in need and for whom services will be most effective. In addition, with a common vocabulary, local communities could more easily develop cohesive plans to address the housing needs of their communities. To improve their understanding of homelessness and to help mitigate the barriers posed by having differences in definitions of homelessness and related terminology, we recommend that the Secretaries of Education, HHS, and HUD—working through the U. S. Interagency Council on Homelessness—take the following two actions: 1. Develop joint federal guidance that establishes a common vocabulary for discussing homelessness and related terms. Such guidance may allow these and other agencies on the Interagency Council on Homelessness to collaborate more effectively to provide coordinated services to those experiencing homelessness. 2. Determine whether the benefits of using this common vocabulary to develop and implement guidance for collecting consistent federal data on housing status for targeted homelessness programs, as well as mainstream programs that address the needs of low-income populations, would exceed the costs. We provided a draft of this report to the Departments of Education, Health and Human Services, Housing and Urban Development, Labor, and Justice and the Executive Director of the Interagency Council for their review and comment. We received comments from the Assistant Secretary of the Office of Elementary and Secondary Education at the Department of Education; the Assistant Secretary for Legislation at the Department of Health and Human Services; the Assistant Secretary of Community Planning and Development at the Department of Housing and Urban Development; and the Executive Director of the Interagency Council. These comments are reprinted in Appendixes III through VI of this report respectively. The Departments of Labor and Justice did not provide formal comments. Education, HUD, and the Executive Director of the Interagency Council explicitly agreed with our first recommendation that Education, HHS, and HUD--working through the Interagency Council--develop federal guidance that establishes a common vocabulary for discussing homelessness and related terms. HHS did not explicitly agree or disagree with this recommendation. Instead, HHS commented extensively on the advantages of having multiple definitions of homelessness. While we discuss the challenges posed by, and the advantages of, having multiple definitions of homelessness in this report, our report recommends a common vocabulary rather than either a single or multiple definitions. In their interagency strategic plan to prevent and end homelessness issued on June 22, 2010, the agencies acknowledge the need for a common vocabulary or language when they say that a common language is necessary for the interagency plan to be understandable and consistent and that this language does not negate or embrace the definitions used by different agencies. Education explicitly addressed our second recommendation that agencies consider the costs and benefits of using a common vocabulary to develop and implement guidance for collecting consistent federal data on housing status for targeted homelessness and mainstream programs in their written response. Education wrote that a discussion of such costs and benefits of using more of a common vocabulary, as it relates to data collection, should be an agenda item for the Interagency Council. The Executive Director of the Interagency Council also supported further exploration of how to accurately and consistently report housing status in mainstream programs. Although we recommend that the agencies work through the council to address this recommendation, decisions about individual program data collection will necessarily be made by the agency overseeing the program. Although HHS did not comment explicitly on our second recommendation, they did provide comments on data collection. They commented that GAO appears to assume that programs identify people who are homeless only to have a total count of the homeless population. We do not make that assumption. We recognize that programs collect data specifically for the program’s use; however, data collected for programs also can contribute to a broader understanding of the extent and nature of homelessness. For example, while HMIS has certain shortcomings described in the report, service providers collect HMIS data in some cases to better manage their programs, and HUD also uses those data to attempt to understand the extent and nature of homelessness. HHS also noted that homelessness data systems are costly and complicated to develop and linking them presents challenges. We acknowledge that while collecting more consistent data on housing status for targeted and mainstream programs would have benefits, there would be implementation costs as well. Additionally, HHS, HUD, and the Executive Director of the Interagency Council raised other concerns about this report that did not relate directly to the two recommendations. HHS commented on the history of the National Youth in Transition Database, developed in response to the Chafee Foster Care Independence Act of 1999. HUD commented that the report did not present a complete view of HUD’s data collection and reporting efforts and did not recognize the strides that have been made in this area, the value of the data currently being collected and reported, or that their Annual Homeless Assessment Report is the only national report to use longitudinal data. The Executive Director of the Interagency Council also wrote that the report did not adequately recognize what is possible today that was not possible 5 years ago. The objective of this report was to determine the availability and completeness of data that currently are collected on those experiencing homelessness, not on the extent to which these data have improved over time. In addition, HUD’s data are not longitudinal in that they do not follow specific individuals over time; rather HUD collects aggregated data that track numbers of homeless over time. Nonetheless, in the report we discuss actions that HUD has taken to improve its homelessness data over time and note the inherent difficulties of collecting these data. The report also notes that HUD’s point-in-time count represents the only effort by a federal agency to count all of those who are experiencing homelessness, rather than just those utilizing federally-funded programs. HUD made a number of other comments related to their data and the definition of homelessness. HUD commented that the report did not recognize that data collection is driven by statutory definitions or that HUD’s point-in-time and HMIS systems are in some sense complementary. We have addressed this comment in the final report by making it clearer that data collected necessarily reflect the definitions included in the statutes that mandate data collection. We also added a footnote to show that while point-in-time counts focus on those who are homeless for long periods of time, HMIS may capture those who are homeless for shorter periods of time or move in and out of homelessness. HUD also commented that the report did not adequately describe the statutory history of homelessness definitions. We do not agree; the report describes the statutory history to the extent needed to address our objectives. Additionally, HUD commented that the report did not provide proper context about HMIS development and implementation at the local level, adding that a community’s success in using HMIS to meet local needs depends on a variety of factors, such as staff experience and the quality of software selected. We revised the report to acknowledge that a community’s success in using HMIS depends on these other factors. Further, the report acknowledges that in setting HMIS data standards, HUD allowed communities to adapt locally developed data systems or to choose from many other HMIS systems that meet HUD’s standards. Finally, HUD wrote that we attribute the lack of collaboration among federal agencies solely to differences in definitions. Similarly, the Executive Director of the Interagency Council wrote that many greater obstacles to effective collaboration exist than the definitional issue—such as “siloed” departmental and agency structures, uncoordinated incentives and measures of effectiveness, difficulties communicating across very large bureaucracies, and different program rules for releasing and administering funds. The report does not attribute the lack of collaboration solely to the differences in definitions. Instead we note that agencies have not collaborated and that having a common vocabulary could improve collaboration. The report focuses on definitional differences, in part, because it was a key objective of our work and an issue frequently raised in discussions of barriers to effectively providing services to those experiencing homelessness. Education, HHS, and HUD also provided technical comments which we addressed as appropriate. We are sending copies of this report to the Secretaries of Education, Health and Human Services, Housing and Urban Development, Labor, and Justice; the Executive Director of the U.S. Interagency Council on Homelessness; and relevant congressional committees. This report will also be available at no charge on GAO’s Web site at http://www.gao.gov. If you or your staff have any questions about this report, please contact me at (202) 512-8678 or cackleya@gao.gov. Contact points for our Offices of Congressional Relations and Public Affairs may be found on the last page of this report. GAO staff who made major contributions to this report are listed in appendix VII. The objectives of our report were to (1) assess the availability, completeness, and usefulness of data on homelessness collected by federal programs; (2) assess the extent to which research identifies factors associated with homelessness; and (3) analyze how differences in the definitions of homelessness and other factors, such as the level of agency collaboration, may impact the effectiveness of programs serving those experiencing homelessness. To address all of our objectives, we reviewed relevant laws such as the McKinney-Vento Homeless Assistance Act, as amended, and the HEARTH Act, as well as a range of prior GAO reports that addressed homelessness or related issues such as reviews of the Social Security Administration’s Supplemental Security Income (SSI) and Supplemental Security Disability Income (SSDI) programs. We also reviewed regulations and government reports across a number of programs specifically targeted to address issues related to homelessness as well as mainstream programs, such as Temporary Assistance for Needy Families (TANF), Head Start, and Public Housing, that often provide services to people experiencing homelessness. Finally, we reviewed research on homelessness retrieved during a wide- ranging search of the literature. During our review, we conducted interviews with at least 60 entities, including officials of six federal government agencies, representatives of at least 15 state and local government entities, staff and officials at 27 service providers, 11 researchers, and officials at 10 groups that advocated for positions related to homelessness. These sum to more than the 60 interviews because some entities fall into more than one category. Specifically, we interviewed officials at the Departments of Education (Education), Health and Human Services (HHS), Housing and Urban Development (HUD), Justice (DOJ), and Labor (DOL), and the U.S. Interagency Council on Homelessness (Interagency Council). We also conducted in-depth interviews with advocates and researchers, as well as service providers, state and local government officials, and HUD field staff that had extensive experience with homeless programs. Many of our interviews were conducted as part of four site visits to large and medium- sized urban areas that were geographically distributed across the United States. We visited these locations to determine the extent to which views on homelessness were specific to particular locations or regions because of local laws, population concentration, or weather. We chose locations to represent each of the major regions of the United States—the Midwest, Northeast, South, and West—and to reflect differences in population concentration and weather. We chose specific urban areas in part because they had reported recent large changes in homelessness among families— two had seen a marked increase, while a third had noted a decrease. In the fourth location, homelessness had been relatively stable. Using these factors, we chose cities in California, Illinois, Massachusetts, and South Carolina. Generally, we did not consider issues specific to rural areas because Congress had mandated a separate study of them. We chose the specific organizations we interviewed to include a range of activities and views, but did not seek to interview a given number of agencies or individuals in each area or to develop a sample from which we could generalize our findings. We also undertook a number of activities specific to each objective: To address the first objective on the availability, completeness, and usefulness of data on homelessness collected by federal programs, we reviewed statutes, regulations, guidance, technical standards, and reports on federal data from targeted homelessness programs. We focused our review of federal data on the Housing and Urban Development Department’s (HUD) Homeless Management Information System (HMIS) and point-in-time counts, Health and Human Services’ (HHS) Runaway and Homeless Youth Management Information System (RHYMIS), and data submitted to the Department of Education through Consolidated State Performance Reports. We interviewed selected service providers to learn about the data systems they use to collect and store information on the homeless populations they serve, the procedures they use to ensure data reliability, and the usefulness of existing data systems for program management and administrative purposes. In addition, we interviewed selected federal, state, and local officials to identify the data used in their oversight of programs for families and individuals that are experiencing homelessness, the procedures they use to verify data reliability, and the extent to which existing data provide sufficient information for program management. Further, we spoke with researchers, individuals with special expertise with federal data systems, and government contractors, to determine the reliability and usefulness of existing data sources on the homeless, as well as to identify potential areas for improvement in data on the homeless. We also analyzed estimates of the extent of homelessness that were derived from federal data systems. In determining the reliability of the data for this report, we identified several limitations with the data– namely, that persons experiencing homelessness are hard to identify and count; that other than the point-in-time count, the three federal data sources for targeted homelessness programs primarily capture data on program participants; and that duplication can exist because the population is mobile and dynamic–which are noted in the report. Nevertheless, because these are the only available data and the relevant departments use them to understand the extent and nature of homelessness, we present the data with their limitations. We also reviewed two HHS reports on homelessness and housing status data collected from federal mainstream programs, to determine the availability of such data. We reviewed research that estimated the size of the population that is doubled up with family and friends. We used data from the 2008 American Community Survey to develop our own estimate of the number of people who were experiencing severe to moderate economic hardship and living with an extended family or nonfamily member in 2008. The survey is conducted annually by the U.S. Census Bureau, and it asks respondents to provide information for housing information and employment income for households. We made several assumptions about what comprises severe or moderate economic hardship. Severe economic hardship was assumed to mean that households had housing costs of at least 50 percent of household income and that household income was below 50 percent of the federal poverty line and moderate economic hardship was assumed to mean that the households had housing costs that were at least 30 percent of household income and household income was below the federal poverty line. We also made assumptions about what comprises extended family; we assumed that extended family households were those where some people in the household were not part of the head of household’s immediate family, and we included spouse, live-in partners, children, grandparents, and grandchildren in our definition of immediate family members. We cannot determine from the available data whether the individuals that are living with extended family or nonfamily members and experiencing severe or moderate economic hardship would meet the McKinney-Vento Children and Youth definition of homelessness, which requires that individuals be doubled up because of economic hardship. Because we followed a probability procedure based on random selections, our sample is only one of a large number of samples that we might have drawn. Since each sample could have provided different estimates, we express our confidence in the precision of our particular sample’s results as a 95-percent confidence interval. This is the interval that would contain the actual population values for 95 percent of the samples we could have drawn. As a result, we cannot determine whether the people in our estimate would be eligible for the benefits if the McKinney-Vento Individual definition of homelessness were expanded to include those doubled up because of economic hardship. To address the second objective, we conducted a literature review to identify research studies that considered factors associated with the likelihood that families, youths, and individuals would experience homelessness. We also used various Internet search databases (including EconLit, ERIC, Medline, and Proquest) to identify studies published or issued after 1998. We chose 1998 as a starting point because welfare reform—which impacted some homeless families—had been implemented by that date and may have affected research findings. We sought to identify additional studies with persons we interviewed (that is, government officials, researchers, and advocacy groups) and from studies’ bibliographies. In this initially broad search, we identified more than 600 studies, although we cannot be certain that we captured all relevant research that met our screening criteria. We screened the papers we identified using a multilevel process to gauge their relevance and evaluate their methodology. We excluded papers that did not specifically focus on our objective, were published or issued before 1998, lacked quantitative analysis, had a target population sample size of less than 25, did not conduct some form of statistical testing, did not use a comparison or control group or some other means to compare the target population (or group of persons to whom the research hopes to generalize findings) such as regression analyses, focused on homeless populations outside of the United States, or were dissertations. We retained 45 studies after screening and reviewed their methodologies, findings, and limitations. Nine GAO staff (four analysts and five methodologists) were involved in the systematic review of each of the 45 studies selected, which were determined to be sufficiently relevant and methodologically rigorous. More specifically, two staff members—one analyst and one methodologist—reviewed each study and reached agreement on the information entered in the database. As noted in this report, many of these studies are subject to certain methodological limitations, which may limit the extent to which the results can be generalized to larger populations. In some cases, studies did not discuss correlation among the factors and are thus limited in their ability to explain which factors might lead to homelessness. In addition, at least four studies used data that were more than 10 years old from the date of publication. Findings based on such data may be limited in explaining the characteristics and dynamics of current homeless populations. Further, collecting comparable information from individuals who have not been homeless (a comparison group) is important in determining which variables distinguish those experiencing homelessness from those that do not, and is essential in determining whether certain at-risk individuals and families experience homelessness and others do not. Although we generally excluded studies that did not use a comparison or control group to test their hypotheses, several studies in our literature review used a comparison group that was another homeless population rather than a nonhomeless control group. In addition to the literature review, we gathered opinions from researchers, advocates, service providers, and government officials on the factors associated with the likelihood of experiencing homelessness. To address the third objective, we took several steps to develop a list of potential barriers to providing services for those experiencing homelessness. First, we reviewed our prior work on barriers facing those experiencing homelessness. Second, we held initial interviews with researchers, service providers, and government officials in our Massachusetts location where potential barriers were raised. Third, in conjunction with a methodologist, we developed a list of potential barriers. The list, which included affordable housing, differences in definitions of homelessness used by various federal agencies, eligibility criteria other than income for accessing mainstream programs, the complexities of applying for grants, and lack of collaboration among federal agencies as well as a number of other potential barriers, was included in a structured data collection instrument to be used in the remaining interviews. We asked those we interviewed to select the three most important barriers from that list but did not ask them to rank order their selections. Interviewees were also able to choose barriers not on the list. To ensure that interviewees were interpreting the items on the list in the same way that we were interpreting them, we had interviewees describe the reasons for their choice. We determined the relative importance of the barriers chosen by summing the number of times an item was selected as one of the three most important barriers. When those we interviewed did not choose differences in definitions of homelessness as one of the three main barriers, we asked them for their views on definitional issues and asked all those we interviewed about the advantages of having multiple definitions of homelessness. Similarly, for collaboration among federal agencies, we asked those we interviewed about the agencies they worked with and, if they worked with multiple agencies, about their experiences. We also asked for examples of successful interaction among federal agencies. collaboration. As previously noted, lack of interagency collaboration was also on the list of barriers. In addition, we interviewed the acting and newly appointed executive directors of the Interagency Council on Homelessness and reviewed certain documents related to their activities; interviewed agency officials at Education, HUD, HHS, DOL, and DOJ; and reviewed agency planning and performance documents to identify coordination with other agencies. We conducted this performance audit from May 2009 to June 2010 in accordance with generally accepted government auditing standards. Those standards require that we plan and perform the audit to obtain sufficient, appropriate evidence to provide a reasonable basis for our findings and conclusions based on our audit objectives. We believe that the evidence obtained provides a reasonable basis for our findings and conclusions based on our audit objectives. We conducted a review of 45 research studies that analyzed factors associated with homelessness. Most of the studies we reviewed examined factors associated with the likelihood of entering an episode of homelessness or the rates of homelessness in a given area, while a few examined factors associated with the duration of homelessness. Twenty- nine studies examined adult individuals, 14 studies examined families, and 7 studies examined only youths. To assess factors associated with homelessness, studies used a range of analytical techniques—including measures of association or correlation between single factors and methods that accounted for some of the interrelationships among factors. The 45 studies are listed below: Allgood, Sam, and Ronald S. Warren, Jr. “The Duration of Homelessness: Evidence from a National Survey.” Journal of Housing Economics 12 (2003): 273-290. Anderson, Debra Gay, and M. K. Rayens. “Factors Influencing Homelessness in Women.” Public Health Nursing 21, no. 1 (2004): 12-23. Bassuk, Ellen L., Jennifer N. Perloff, and Ree Dawson. “Multiply Homeless Families: The Insidious Impact of Violence.” Housing Policy Debate 12 (2001): 299-320. Bendheim-Thoman Center for Research on Child Wellbeing and Columbia Population Research Center. “Predictors of Homelessness and Doubling- up Among At-risk Families.” Fragile Families Research Brief, no. 43 (August 2008). Caton, Carol L. M., Boanerges Dominguez, Bella Schanzer, et al. “Risk Factors for Long-Term Homelessness: Findings from a Longitudinal Study of First-Time Homeless Single Adults.” American Journal of Public Health 95 (2005): 1753-1759. Caton, Carol L. M., Deborah Hasin, Patrick E. Shrout, et al. “Risk Factors for Homelessness among Indigent Urban Adults with No History of Psychotic Illness: A Case-Control Study.” American Journal of Public Health 90 (2000): 258-263. Collins, Cyleste C., Claudia J. Coulton, and Seok-Joo Kim. Family Homelessness in Cuyahoga County. White paper published for the Sisters of Charity Foundation, Center on Urban Poverty and Community Development, Cleveland, Ohio: Case Western Reserve University, 2009. Cousineau, Michael R. “Comparing Adults in Los Angeles County Who Have and Have Not Been Homeless.” Journal of Community Psychology 296, no. 6 (2001): 693-701. Culhane, Dennis P., and Stephen Metraux. “One-Year Rates of Public Shelter Utilization by Race/Ethnicity, Age, Sex and Poverty Status for New York City (1990 and 1995) and Philadelphia (1995).” Population Research and Policy Review (1999): 219-236. Culhane, Dennis P., Stephen Metraux, Stephen R. Poulin, and Lorlene M. Hoyt. “The Impact of Welfare Reform on Public Shelter Utilization in Philadelphia: A Time-Series Analysis.” Cityscape: A Journal of Policy Development and Research, U.S. Department of Housing and Urban Development, Office of Policy Development and Research 6, no. 2 (2003): 173-185. Early, Dirk W. “An Empirical Investigation of the Determinants of Street Homelessness.” Journal of Housing Economics 14 (2005): 27-47. Early, Dirk W. “The Determinants of Homelessness and the Targeting of Housing Assistance.” Journal of Urban Economics 55 (2004): 195-214. Early, Dirk W. “The Role of Subsidized Housing in Reducing Homelessness: An Empirical Investigation Using Micro-Data.” Journal of Policy Analysis and Management 17, no. 4 (1998): 687-696. Eyrich-Garg, Karin M., John S. Cacciola, Deni Carise, et al. “Individual Characteristics of the Literally Homeless, Marginally Housed, and Impoverished in a U.S. Substance Abuse Treatment-Seeking Sample.” Social Psychiatry and Psychiatric Epidemiology 43 (2008): 831-842. Eyrich-Garg, Karin M., Catina Callahan O’Leary, and Linda B. Cottler. “Subjective Versus Objective Definitions of Homelessness: Are There Differences in Risk Factors among Heavy-Drinking Women?” Gender Issues 25 (2008): 173-192. Fertig, Angela R., and David A. Reingold. “Homelessness among at-Risk Families with Children in Twenty American Cities.” Social Service Review 82, no. 3 (2008): 485-510. Fitzgerald, Scott T., Mack C. Shelley II, and Paula W. Dail. “Research and Homelessness: Sources and Implications of Uncertainty.” American Behavioral Scientist 45, no. 1 (2001): 121-148. Folsom, David P., William Hawthorne, Laurie Lindamer, et al. “Prevalence and Risk Factors for Homelessness and Utilization of Mental Health Services Among 10,340 Patients with Serious Mental Illness in a Large Public Mental Health System.” American Journal of Psychiatry 162, no. 2 (2005): 370-376. Greenberg, Greg A., and Robert A. Rosenheck. “Homelessness in the State and Federal Prison Population.” Criminal Behaviour and Mental Health 18, no. 2 (2008): 88-103. Gubits, Daniel, Jill Khadduri, and Jennifer Turnham. Housing Patterns of Low Income Families with Children: Further Analysis of Data from the Study of the Effects of Housing Vouchers on Welfare Families. Joint Center for Housing Studies of Harvard University, 2009. Ji, Eun-Gu. “A Study of the Structural Risk Factors of Homelessness in 52 Metropolitan Areas in the United States.” International Social Work 49, no. 1 (2006): 107-117. Johnson, Timothy P., and Michael Fendrich. “Homelessness and Drug Use - Evidence from a Community Sample.” American Journal of Preventive Medicine 32 (2007): S211-S218. Kingree, J. B., Torrance Stephens, Ronald Braithwaite, and James Griffin. “Predictors of Homelessness among Participants in a Substance Abuse Treatment Program.” American Journal of Orthopsychiatry 69, no. 2 (1999): 261-266. Kuhn, Randall, and Dennis P. Culhane. “Applying Cluster Analysis to Test a Typology of Homelessness by Pattern of Shelter Utilization: Results from the Analysis of Administrative Data.” American Journal of Community Psychology 26 (1998): 207-232. Leal, Daniel, Marc Galanter, Helen Dermatis, and Laurence Westreich. “Correlates of Protracted Homelessness in a Sample of Dually Diagnosed Psychiatric Inpatients.” Journal of Substance Abuse Treatment 16, no. 2 (1999): 143-147. Lee, Barrett A., Townsand Price-Spratlen, and James W. Kanan. “Determinants of Homelessness in Metropolitan Areas.” Journal of Urban Affairs 25 (2003): 335-355. Lehmann, Erika R., Philip H. Kass, Christiana M. Drake, and Sara B. Nichols. “Risk Factors for First-Time Homelessness in Low-Income Women.” American Journal of Orthopsychiatry 77, no. 1 (2007): 20-28. Metraux, Stephen, and Dennis P. Culhane. “Family Dynamics, Housing, and Recurring Homelessness among Women in New York City Homeless Shelters.” Journal of Family Issues 20, no. 3 (1999): 371-396. Molino, Alma C. “Characteristics of Help-Seeking Street Youth and Non- Street Youth.” 2007 National Symposium on Homelessness Research, 2007. O’Flaherty, Brendan, and Ting Wu. “Fewer Subsidized Exits and a Recession: How New York City’s Family Homeless Shelter Population Became Immense.” Journal of Housing Economics (2006): 99-125. Olsen, Edgar O., and Dirk W. Early. “Subsidized Housing, Emergency Shelters, and Homelessness: An Empirical Investigation Using Data from the 1990 Census.” Advances in Economic Analysis & Policy 2, no. 1 (2002). Orwin, Robert G., Chris K. Scott, and Carlos Arieira. “Transitions through Homelessness and Factors That Predict Them: Three-Year Treatment Outcomes.” Journal of Substance Abuse Treatment 28 (2005): S23-S39. Park, Jung Min, Stephen Metraux, and Dennis P. Culhane. “Childhood Out- of-Home Placement and Dynamics of Public Shelter Utilization among Young Homeless Adults.” Children and Youth Services Review 27, no. 5 (2005): 533-546. Quigley, John M., Steven Raphael, and Eugene Smolensky. “Homeless in America, Homeless in California.” The Review of Economics and Statistics 83, no. 1 (2001): 37-51. Rog, Debra J. C., Scott Holupka, and Lisa C. Patton. Characteristics and Dynamics of Homeless Families with Children. Final report to the Office of the Assistant Secretary for Planning and Evaluation, Office of Human Services Policy, U.S. Department of Health and Human Services (Rockville, Md.: Fall 2007). Shelton, Katherine H., Pamela J. Taylor, Adrian Bonner, and Marianne van den Bree. “Risk Factors for Homelessness: Evidence from a Population- Based Study.” Psychiatric Services 60, no. 4 (2009): 465-472. Shinn, Marybeth, Beth C. Weitzman, Daniela Stojanovic, and James R. Knickman. “Predictors of Homelessness among Families in New York City: From Shelter Request to Housing Stability.” American Journal of Public Health 88, no. 11 (1998): 1651-1657. Slesnick, Natasha, Suzanne Bartle-Haring, Pushpanjali Dashora, et al. “Predictors of Homelessness among Street Living Youth.” Journal of Youth Adolescence 37 (2008): 465-474. Stein, Judith A., Michelle Burden Leslie, and Adeline Nyamathi. “Relative Contributions of Parent Substance Use and Childhood Maltreatment to Chronic Homelessness, Depression, and Substance Abuse Problems among Homeless Women: Mediating Roles of Self-Esteem and Abuse in Adulthood.” Child Abuse & Neglect 26, no. 10 (2002): 1011-1027. Sullivan, G., A. Burnam, and P. Koegel. “Pathways to Homelessness among the Mentally Ill.” Social Psychiatry and Psychiatric Epidemiology 35 (2000): 444-450. Tyler, Kimberly A., and Bianca E. Bersani. “A Longitudinal Study of Early Adolescent Precursors to Running Away.” Journal of Early Adolescence 28, no. 2 (2008): 230-251. The Urban Institute, Martha R. Burt, Laudan Y. Aron, et al. Homelessness: Programs and the People They Serve: Findings of the National Survey of Homeless Assistance Providers and Clients. 1999. Vera Institute of Justice, Nancy Smith, Zaire Dinzey Flores, et al. Understanding Family Homelessness in New York City: An In-Depth Study of Families’ Experiences Before and After Shelter 2005. Whaley, Arthur L. “Demographic and Clinical Correlates of Homelessness among African Americans with Severe Mental Illness.” Community Mental Health Journal 38, no. 4 (2002): 327-338. Yoder, Kevin A., Les B. Whitbeck, and Dan R. Hoyt. “Event History Analysis of Antecedents to Running Away from Home and Being on the Street.” American Behavioral Scientist 45, no. 1 (2001): 51-65. In addition to the individual named above, Paul Schmidt, Assistant Director; Nancy S. Barry; Katie Boggs; Russell Burnett; William Chatlos; Kimberly Cutright; Marc Molino; Barbara Roesmann; Paul Thompson; Monique Williams; and Bryan Woliner made major contributions to this report.

Summary: Multiple federal programs provide homelessness assistance through programs targeted to those experiencing homelessness or through mainstream programs that broadly assist low-income populations. Programs' definitions of homelessness range from including primarily people in homeless shelters or on the street to also including those living with others because of economic hardship. GAO was asked to address (1) the availability, completeness, and usefulness of federal data on homelessness, (2) the extent to which research identifies factors associated with experiencing homelessness, and (3) how differences in definitions and other factors impact the effectiveness of programs serving those experiencing homelessness. GAO reviewed laws, agency regulations, performance and planning documents, and data as well as literature on homelessness, and spoke with stakeholders, such as government officials and service providers, about potential barriers. Federal agencies, including the Departments of Education (Education), Health and Human Services (HHS), and Housing and Urban Development (HUD), collect data on homelessness. However, these data are incomplete, do not track certain demographic information well over time, and are not always timely. HUD collects data and estimates the number of people who are homeless on a given night during the year and the number who use shelters over the course of the year; these estimates include the people who meet the definition of homelessness for HUD's programs, but do not include all of those who meet broader definitions of homelessness used by some other agencies' programs. For example, HUD's counts would not include families living with others as a result of economic hardship, who are considered homeless by Education. Data from federally-funded mainstream programs such as HHS's Temporary Assistance for Needy Families could improve agencies' understanding of homelessness, but these programs have not consistently collected or analyzed information on housing status because this is not their primary purpose. Because research studies GAO reviewed often used different definitions of homelessness, relied on data collected at a point-in-time, and focused narrowly on unique populations over limited geographical areas, the studies cannot be compared or compiled to further an understanding of which factors are associated with experiencing homelessness. Furthermore, although researchers GAO interviewed and most studies noted the importance of structural factors such as area poverty rates, and those that analyzed these factors found them to be important, few studies considered them. Most of the studies analyzed only the association of individual-level factors such as demographic characteristics, but these studies often did not consider the same individual-level factors or agree on their importance. Many of the government officials, service providers, advocates, and researchers GAO interviewed stated that narrow or multiple definitions of homelessness have posed challenges to providing services for those experiencing homelessness, and some said that having different definitions made collaborating more difficult. For example, some said that persons in need of services might not be eligible for programs under narrower definitions of homelessness or might not receive services for which they were eligible because of confusion created by multiple definitions. Different definitions of homelessness and different terminology to address homelessness have made it difficult for communities to plan strategically for housing needs and for federal agencies such as Education, HHS, and HUD to collaborate effectively to provide comprehensive services. As long as agencies use differing terms to address issues related to homelessness, their efforts to collaborate will be impeded, and this in turn will limit the development of more efficient and effective programs. Commenting on a draft of this report, HHS and HUD raised concerns about its treatment of homelessness data. We characterize and respond to those comments within the report. GAO recommends that Education, HHS, and HUD (1) develop a common vocabulary for homelessness; and (2) determine if the benefits of collecting data on housing status in targeted and mainstream programs would exceed the costs. To the extent that the agencies explicitly addressed the recommendations in their comments, they agreed with them.