ENCOURAGING HEALTH INSURANCE FOR THE INFORMAL SECTOR: A CLUSTER RANDOMIZED EXPERIMENT IN VIETNAM

Subsidized voluntary enrollment in government-run health insurance schemes is often proposed as a way of increasing coverage among informal sector workers and their families. We report the results of a cluster randomized experiment, in which 3000 households in 20 communes in Vietnam were randomly assigned at baseline to a control group or one of three treatments: an information leaflet about Vietnam's government-run scheme and the benefits of health insurance, a voucher entitling eligible household members to 25% off their annual premium, and both. At baseline, the four groups had similar enrollment rates (4%) and were balanced on plausible enrollment determinants. The interventions all had small and insignificant effects (around 1 percentage point or ppt). Among those reporting sickness in the 12months prior to the baseline survey the subsidy-only intervention raised enrollment by 3.5ppts (p=0.08) while the combined intervention raised enrollment by 4.5ppts (p=0.02); however, the differences in the effect sizes between the sick and non-sick were just shy of being significant. Our results suggest that information campaigns and subsidies may have limited effects on voluntary health insurance enrollment in Vietnam and that such interventions might exacerbate adverse selection. Copyright (C) The World Bank Health Economics (c) 2015 John Wiley & Sons, Ltd.