There is growing enthusiasm for leveraging big data to inform and accelerate development, by strengthening the evidence base for more effective, responsible, and inclusive development investments. In a world where data often lags the pace of human progress, big data offers extraordinary potential to provide near real-time estimations of the number and locations of people. Big data can support national development efforts during or after humanitarian crises, in the midst of mass movements of people or when governments need to estimate the size, location and composition of their population during or after conflict, when official data collection systems may be undermined.