Project Summary The lack of safe and affordable housing reflects a national crisis. While research has documented the harms of housing insecurity on children’s health, little work has examined the ways in which housing subsidies may help protect children’s health from this threat. Housing vouchers, which subsidize the costs or rent and utilities and enable low-income families to rent homes on private market, is the nation’s largest housing assistance program. However, only a quarter of eligible households receive rental assistance. As policy-makers and practitioners consider ways to optimize the use of existing vouchers and seek support to expand the overall supply of affordable housing, there is a critical need for research that investigates the link between housing choice vouchers and health. Working with two public housing authorities (Seattle Housing Authority and King County Housing Authority) and a health department (Public Health –Seattle & King County), we intend to investigate the association between the receipt of a housing voucher on children’s enrollment in Medicaid and patterns of health care use. The proposal uses quasi-experimental difference-in-differences methods leveraging the fact that families who receive housing assistance are randomly selected from a long waitlist (N>40,000), thereby reducing potential confounding. The proposal extends a unique data linkage performed by the public housing authorities and health department in which administrative housing data has been successfully linked with Medicaid claims and encounter data. In the first aim, we will use a difference-in- difference approach to investigate whether the receipt of a housing choice voucher is associated with changes in Medicaid enrollment compared to those on the waitlist. The second aim studies whether children whose families receive a housing choice voucher have different patterns of hospitalization, emergency department visits, ‘housing-sensitive’ conditions (including asthma, other respiratory conditions, mental health and injuries) and well-child visits compared to those on the waitlist. The final aim examines whether important child factors such as age, gender, and race/ethnicit modify the associations between housing vouchers and health care use. The proposal brings together academic researchers with public housing and public health authorities with the strong potential to translate the results into actionable policy recommendations and practice designed to improve children’s health and well-being.