As part of our big data work, I have been looking at the 2012 Sri Lanka census preliminary results based on five percent of the responses. The picture that emerges is a far cry from the slums described in this Economist summary of research on slums: Yet the MIT paper, which offers simple statistics about 138,000 slum households from around the world, suggests that slums are often an impediment to advancement. Poor hygiene, and the debilitating illnesses it propagates, is one curse. The majority of slum-dwellers in the MIT sample have no private latrine; in one Mumbai slum, taps are shared by more than 100 people. According to the African Population and Health Research Centre hygiene is regularly worse in slums than in rural areas.