Estimating Aggregate Policy Reform Effects: New Baselines for Registration, Participation, and Representation

Statistical models are often extended to explore the aggregate impact of policy reforms. After discussing these techniques and the incorporation of prediction uncertainty, this article examines the effects of registration reform in an analytic framework that explicitly considers the two stages that defined electoral participation throughout the 20th century in the United States—registration and then voting. Using selection bias techniques, the effects of counterfactual registration reform conditions are explored on the aggregate level of participation and the nature of representation in the electoral process. These offer a richer baseline of the impact of policy changes than previous work by directly exploring the expected level of dropoff in going to the polls by new registrants. Results indicate that the dropoff between registration and voting would be expected to increase as more individuals become registered. In addition, while turnout due to reforms among projected “new registrants†shows potentially larger biases than those among existing registrants, because of the different bases of registration the changes would still lead to a modest reduction in the disparity between actual group sizes and their role in elections.