Citation:
Sinclair, B., Rogowski, J.B., Bass, A. and Harrington, J., 2011. Design and analysis of experiments in multilevel populations. Cambridge handbook of experimental political science.
Randomized experiments, the most rigorous methodology for testing causal explanations for phenomena in the social sciences, are experiencing a resurgence in political science. The classic experimental design randomly assigns the population of interest into two groups, treatment and control. Ex ante these two groups should have identical distributions in terms of their observed and unobserved characteristics. Treatment is administered based on assignment, and by the assumptions of the Rubin causal model, the average effect of the treatment is calculated as the difference between the average outcome in the group assigned to treatment and the average outcome in the group assigned to control.
