Evaluating the Economic Effects of Flat Tax Reforms Using Synthetic Control Methods

Tax reforms are often motivated by their potential to improve economic performance. However, their actual impacts are difficult to quantify. We analyze the impact of flat tax reform on incomes using “synthetic control” methods. We identify the eight Eastern and Central European countries that adopted flat tax systems between 1994 and 2005, and then compare post‐reform GDP per capita of “treated” countries with a convex combination of similar but “untreated” countries, while accounting for the time‐varying impact of unobservable heterogeneity. We find positive impacts in all eight countries, with seven out of eight cases significant at the conventional level.