Résumé en anglais

In order to improve financial access to complementary health insurance (CHI) in France, a CHI voucher program, called Aide Complémentaire Santé (ACS) was introduced in 2005. Four years later, the program covered only 18% of the eligible population. Two main hypotheses are put forward to account for this low take-up rate. The first one is related to the lack of information on the program itself and on its application process. While the second one considers that the amount of the financial support is too small to encourage people to purchase a CHI plan. We conduct a controlled experiment with the National Health Insurance Fund in order to assess these assumptions. A sample of eligible insurees living in an urban area in northern France were randomly split into three groups: a control group who received the standard level of financial aid, a group benefiting from a 75% voucher increase, and a third group benefiting from the same 75% voucher increase plus an invitation to an information meeting on ACS. After six months of follow-up, we observed how many application forms were sent back and how many of them entitled to ACS. Five main conclusions can be drawn from that analysis. (1) The voucher increase has a slight but statistically significant effect on ACS take-up. (2) It also allows better targeting of people actually eligible and thus reduces the number of ACS refusals due to resources above the upper limit. (3) However the invitation to the meeting seems unexpectedly to cancel the positive effect of the voucher increase when both treatments are applied jointly. (4) On the contrary, after controlling for potential selection bias, we observed that attending the briefing has a significant impact on ACS take-up. (5) This study confirms that ACS is complex and reaches poorly its target population. Only 17% of the insurees applied for ACS and only 9% of insures who were invited to the information briefing actually attended it. Moreover, previous CHI holders responded similarly to CHI non holders to treatments, which suggests that the central issue of ACS low take-up rate is not the CHI cost itself but most certainly the access to information, the burden and the complexity of the application process.