Estimates of the prevalence of chronic homelessness vary depending on the definition used, the duration of time observed, and the method of data analysis. Based on applications for homeless assistance submitted to HUD from local areas across the country, the National Alliance to End Homelessness (2006a) estimated that there were 150,000 to 200,000 chronically homeless individuals nationwide as of January 2005.
Overall, about 20 percent of sheltered homeless adults would qualify as chronically homeless according to the federal definition, which combines single long spells of homelessness with episodic or recurrent homeless spells. Kuhn and Culhane (1998) studied shelter utilization patterns based on administrative data in New York City and Philadelphia. A cluster analysis of the New York City data revealed that approximately 10 percent of shelter entrants were chronically homeless, remaining in the shelter for an average of over 630 days and experiencing an average of 2.26 episodes over the three years of the study. This group consumed half the total shelter days, despite their small number. Another 10 percent were episodically homeless, shuttling in and out of shelters and other institutions such as hospitals, substance abuse treatment programs, and jails. A cluster analysis of the one-week estimate in the NSHAPC study classified 27 percent as chronically homeless (Burt et al., 2001). This group had an average duration of homelessness in excess of four years. Kertesz et al. (2005) classified 22 percent of study participants as chronically homeless in a two-year follow-up study employing the two-dimensioned federal definition of homelessness. Similarly, a New York City study of first-time homeless sheltered single adults (Caton et al., 2005) found that about 20 percent of study participants remained continuously homeless over a follow-up period of 18 months.