This US-based social experiment assessed the association of personal, individual health with the social and economic environments in which people reside. From 1994 through 1998, the Department of Housing and Urban Development randomly assigned 4,498 women with children living in public housing in high-poverty urban census tracts (in which ≥40% of residents had incomes below the federal poverty threshold) to one of three groups: 1,788 received housing vouchers, which were redeemable only if they moved to a higher census income tract, and counselling on moving; 1,312 received unrestricted, traditional vouchers, with no special counselling on moving; the remaining 1,398 (controls) were offered neither of these opportunities. During 2008–2010, the study collected data on health outcomes, including height, weight, and level of glycated haemoglobin (HbA1c). At follow-up, the rates of a body mass index (BMI) of ≥35, a BMI of ≥40, and a glycated haemoglobin level of ≥6.5% were lower in the group receiving the low-poverty vouchers than in the control group, with an absolute difference of 4.61 percentage points, 3.38 percentage points, and 4.31 percentage points, respectively; the between-group differences were not significant.