Comparison of State Hospital Visits With Housing and Urban Development Estimates of Homeless: Illinois, 2011-2018.

Objectives. To assess the value of hospital records in augmenting information on homelessness counts at a state level.Methods. We used data from the Illinois Hospital Discharge Database (2011-2018) to identify outpatients and inpatients identified as affected by homelessness. We used probabilistic linkage methodology to estimate unique individuals rather than visits and compared them with US Department of Housing and Urban Development annual estimates of homelessness based on point-in-time counts.Results. Department of Housing and Urban Development point-in-time estimates indicate a substantial decline of approximately 24% in homelessness in Illinois; however, estimates of unique individuals visiting the hospital with a code for homelessness more than doubled in this same period.Conclusions. Other data sources, such as hospital records, are increasingly able to identify and report information related to homelessness. Using these additional data sources may help to augment the Department of Housing and Urban Development point-in-time estimates to provide more accurate estimates of homelessness that are used to direct resources and assess policy and support services for those affected by homelessness.