Taxation and growth: Why does it matter and how can it be analysed?

The growth impact of tax reforms is probably one of the most controversial issues in economic policy discussions, reflecting deep beliefs in the way economic agents are expected to react to policy changes. The optimal tax theory literature provides a wide array of arguments to identify the mechanisms through which tax reforms might influence growth, depending on the tax category considered and the circumstances under which tax reforms are implemented. The empirical literature has relied on the use of cross-country growth regressions and provided general results leading to normative conclusions on the desirability of specific tax reform options. However, recent research has shown that this approach yields inconclusive results, notably due to identification and endogeneity issues, and the difficulty to account for the true determinants of governments' actions. The dynamic scoring approach combining microsimulation and macro models proves more useful in this respect, especially in order to draw policy recommendations while accounting for the second-round effects of tax reforms. I illustrate these arguments by analysing the growth impact of a hypothetical change from the current flat personal income tax (PIT) rates to progressive taxes in Central and Eastern European (CEE) countries. I find that the estimated impact of such a reform would be rather small but positive when using the dynamic scoring method, while the less-reliable traditional growth regressions would suggest adverse growth effects.