“…Despite the recent and increasing interest in health insurance programs for excluded populations in developing countries (Preker et al, 2002;Gumber and Kulkarni, 2000;Franco et al, 2008;Smith and Sulzbach, 2008), there is little rigorous evidence on the optimal design of voluntary health insurance schemes targeting the informal sector in terms of their ability to attract a large enough pool of individuals or to increase utilization of quality health services. For instance, in many developing countries, existing synergies between the delivery of financial services and health services to clients in the informal sector have led policy-makers to believe that microfinance institutions (MFIs) may be a promising delivery agent to extend health insurance to low-income and other vulnerable groups (Matin et al, 2002;Churchill, 2003;Churchill and Cohen, 2006), particularly in settings where MFI penetration is high.…”