Stephen Knack is a Lead Economist in the Development Research Group of the World Bank (Human Development and Public Services Team). His recent research addresses the impact of aid on policy reform and on public sector capacity and accountability. Prior to joining the Bank in 1999, Knack was a Research Associate at the University of Maryland's IRIS Center, and Assistant Professor in the School of Public Affairs at American University. He received a PhD in Economics from the University of Maryland in 1991.