David Powell is an Associate Economist at RAND. He received his Ph.D. at MIT. His dissertation work focused on the impacts of income taxes on individual and firm behavior. Specifically, he studied how changes in income tax rates affected pre-tax wages, occupational choice, and labor earnings. Dr. Powell also has a strong econometric background. He has written several papers that extend quantile estimation to new, useful contexts. This work has centered on the inclusion of fixed effects in quantile models and has included instrumental variable extensions as well.