In this week's BMJ, a cluster randomised controlled trial by Ranson and colleagues describes a community based health insurance scheme run by the Self Employed Women's Association (SEWA) in Gujarat, India.1 Community based health insurance is a valuable way to finance the delivery of health services in developing countries. By combining the risk of falling sick with resources, such insurance facilitates access to care and offers financial protection against the cost of illness. In doing so, community based health insurance aims to overcome inequities in access and socioeconomic status by reducing existing gaps between the poor and the less poor.

Research from Asia and sub-Saharan Africa shows that community based health insurance has been less effective in securing equity than expected. Poor people are less likely to enrol in …