Elizabeth M. Foster is an economist in the World Bank’s Poverty and Equity Global Practice in West and Central Africa. She lived in Sierra Leone for over 15 years while working for the World Bank and various nongovernmental organizations and research organizations. Her work focuses on the welfare dynamics of households in the Sahel region and the best practice for measurement of poverty using both international and national measures. She holds a BA degree in mathematics from Harvard University and a master’s degree in public affairs from Princeton University.