More and more people move across and within the borders of their country of birth — freely, in the search of better opportunities; sometimes forcibly to flee conflict, persecution or starvation; or more often due to a combination of factors. New data sources such as cell phone records and social media data, combined with traditional survey data and official statistics, can yield unique insights into the drivers and effects of population movements in both ‘sending’ and ‘host’ communities. Our goal is to contribute to more informed policy discussion and decisions on one of the most contentious issues of our time.