摘要：Objectives. We modeled rates of family and single-adult homelessness in the United States in metropolitan and nonmetropolitan regions and as a function of community-level demographic, behavioral, health, economic, and safety net characteristics. Methods. We entered community-level characteristics and US Department of Housing and Urban Development point-in-time counts for a single night in January 2009 into separate mixed-effects statistical analyses that modeled homelessness rates for 4 subpopulations: families and single adults in metropolitan and nonmetropolitan regions. Results. Community-level factors accounted for 25% to 50% of the variance in homelessness rates across models. In metropolitan regions, alcohol consumption, social support, and several economic indicators were uniquely associated with family homelessness, and drug use and homicide were uniquely associated with single-adult homelessness. In nonmetropolitan regions, life expectancy, religious adherence, unemployment, and rent burden were uniquely associated with family homelessness, and health care access, crime, several economic indicators, and receipt of Supplemental Security Income were uniquely associated with single-adult homelessness. Conclusions. Considering homeless families and single adults separately enabled more precise modeling of associations between homelessness rates and community-level characteristics, indicating targets for interventions to reduce homelessness among these subpopulations. On a single night in January 2012, 394 379 single adults accounted for 62% of the total number of people experiencing homelessness in the United States, and 239 403 persons in homeless families accounted for the remaining 38%. 1 Although homeless single adults outnumber persons in homeless families, each group represents a significant proportion of the total homeless population, and each possesses unique risk factors as well as pathways into and through the experience of homelessness. 1 Gaps in the understanding of these 2 homeless subpopulations persist, despite improvements in data collection. Although previous studies of homeless families and individuals have identified differences in health, behavioral, and demographic characteristics as well as patterns of homelessness, the extent to which these contrasts indicate the causal factors that contribute to their homelessness remains unclear. 2–4 Several causal models of homelessness have integrated both individual- and community-level factors. These models have asserted that homelessness results from a convergence of factors at multiple levels: characteristics and experiences of individuals and households, as well as conditions and forces acting on communities. Community-level studies investigating the relationship between structural factors and community-level variation in total homelessness rates have translated into multidimensional models of homelessness; however, these studies have generally not stratified by household status. 5–7 In this article, we adopt the multidimensional framework for homelessness and assert that the set of predictive variables will differ among household types and among regions. To date, little progress has been made in testing multidimensional models of homelessness separately for subpopulations of families and single adults; few studies have addressed the role that individual-level characteristics and behaviors play in the causal processes of homelessness for both families and single adults relative to community-level factors such as housing costs and unemployment rates. Progress in answering these questions has, up to this point, been stalled by gaps in the available data on homelessness. Studies that have identified differences in family and single-adult homelessness have often focused on individual-level characteristics because data that distinguish between family and single-adult homelessness have been available primarily at the individual or household level. Studies examining geographic variation in rates of homelessness have often had divergent findings with respect to the community-level factors identified as significant predictors of variation in homelessness across communities. The most consistent set of findings has been a positive relationship between homelessness rates and rental market variables (e.g., median rent, presence of low-cost rental housing; D.W. Early and E.O. Olsen, unpublished manuscript, 2001). 7–18 Many studies have demonstrated relationships between homelessness rates at the community level and rental tenure, residential mobility, poverty, and unemployment (all positive), as well as rental vacancy rates (negative), although not all factors were statistically significant in all studies. 5–7,9–13,16,18–20 By contrast, measures derived from social safety net programs (e.g., Temporary Assistance for Needy Families, proportion of the population receiving benefits) have inconsistently predicted homelessness rates. 5,8,9,11–15,20,21 Few studies have included crime statistics in their models; among those that have, 2 found no association between crime rates and homelessness (D.W. Early and E.O. Olsen, unpublished manuscript, 2001), 17 and a third found the violent crime rate to be positively associated with homelessness. 10 A possible explanation for the divergence in results across studies is the lack of differentiation between and separate examination of family and single-adult subpopulations experiencing homelessness. Only 3 studies have distinguished between family and single-adult homelessness rates in their outcomes: 2 used data from a single state, and the other used data from a single city. 10,16,20 These studies found that economic factors—especially housing market indicators—were more significantly related to family than to single-adult homelessness. A robust literature differentiating family and single-adult homelessness, and using data from a diverse set of jurisdictions, has yet to be developed and does not, at this time, support specific hypotheses. By exploring geographical variation at the national level as a function of demographic, behavioral, public health, economic, and safety net factors, we tested the assertion that the sets of variables predicting rates of family and single-adult homelessness differ. Including both subpopulations in 1 study permits a comparison of factors associated with homelessness among these populations as well as the development of more precise models of homelessness. Furthermore, we conceptualized homelessness as a challenging problem for all communities by exploring such associations in both metropolitan and nonmetropolitan regions.
