Doolittle joined MDRC in 1986, initially specializing in studies of employment and training programs for economically disadvantaged out-of-school young people and adults. As MDRC expanded its work to include education, he focused on evaluations of elementary and secondary school reforms. Doolittle has served as project director for national, school-level random assignment studies of teacher professional development and curricular reforms in math and reading, supplemental instruction programs within school and outside the usual school hours, and a school-based program to support the social and emotional development of children. He has also led nonexperimental studies of secondary school reforms and Response to Intervention programs. The author of many publications, Doolittle directs MDRC’s K-12 Education Policy Area. He develops research designs for new projects and reviews reports and other products. He has served on the faculties of Harvard University’s John F. Kennedy School of Government, the Woodrow Wilson School of Public and International Affairs at Princeton University, and the Yale School of Management. Doolittle holds a law degree and a PhD in economics from the University of California at Berkeley.