David N. Weil's research explores the determinants of economic growth and income differences among countries. In recent work with S-4 Associate Vernon Henderson and Adam Storeygard, Weil uses satellite measurements of visible light to improve the estimates of GDP growth in countries where national statistical systems are poor or nonexistent. The tools developed in this project can also be used to estimate income growth for sub- and trans-national regions. His recent research has also examined international flows of populations over the last 500 years. In ongoing research, Weil uses a variety of geographic datasets to examine the historical role of malaria in shaping African development. In another project, he is looking at the determinants of the geographic pattern of economic activity at the world level. Weil is a Research Associate of the National Bureau of Economic Research and co-director of the NBER's project on African Development Successes.