His research interests include voting behavior, redistricting, Congress, American political development, and political methodology. His research appears in American Political Science Review, American Journal of Political Science, Journal of Politics, Political Analysis, State Politics and Policy Quarterly, and PS: Political Science and Politics. He is currently working on a book with Micah Altman and Jeff Gill entitled Statistical Computing for the Social Sciences. His voter turnout research shows that turnout has not been declining, the ineligible population is rising. This research has been featured in the popular press, and he provides voter turnout numbers to academia and the media.
On the practical side of politics, McDonald has worked on campaign staff for state legislative campaigns in California, has worked for national polling firms, and has worked as a redistricting consultant in Alaska, Arizona, California, and Michigan.
McDonald received his B.S. of Economics from California Institute of Technology and his Ph.D. of Political Science from University of California, San Diego in 1999. He was awarded a one-year post-doctoral fellowship at the Harvard-MIT Data Center. He held a one-year Assistant Professor appointment at Vanderbilt University, and was Assistant Professor of Political Studies at University of Illinois, Springfield before moving to George Mason University.