A CREDIT paper now out in Food Policy uses some fancy maths to suggest that the health and nutritional status of Rwandese rural people is more dependent on how much beans, sweet potatoes and other crops they produce, rather than on their income. That’s because of “market imperfections,” which is a polite way of saying that there are no markets. A sobering thought for those development agencies which pin all their hopes on the private sector. The author doesn’t discuss this, but I would have thought the dataset is a suitable one to investigate the relationship between dietary diversity (using the proxy of production diversity) and health. Tragically — and actually rather surprisingly — output of local beer has a significant negative effect on nutrition and no effect on health.