As economists increasingly help governments design new policies and regulations, they take on an added responsibility to engage with the details of policy making and, in doing so, to adopt the mindset of a plumber. Plumbers try to predict as well as possible what may work in the real world,...

This paper uses household surveys from 13 developing countries to describe consumption choices, health and education investments, employment patterns and other features of the of the economic lives of the middle classes defined as those whose daily consumption per capita is between $2 and $4 or...