Progressive Taxation and Social Welfare: Quantifying the Effects of the “German Tax-Reform 2000”

The German “Tax-Reform 2000” involved a strong reduction in the progressivity of labor income taxation. It led to a rise in overall labor income, but also increased income inequality. Utilizing data from the German Socio-Economic Panel (SOEP. 2016. Socio-Economic Panel (SOEP), Data for Years 1984–2016, Version 33) for the years 1998–2007, we employ a general equilibrium framework à la Antràs et al. (Antràs, P., A. De Gortari, and O. Itskhoki. 2017. “Globalization, Inequality and Welfare.” Journal of International Economics 108: 387–412) characterized by heterogeneous individuals. The model imposes a constant rate of tax progressivity and allows for a theory-consistent decomposition of social welfare that highlights the equity-efficiency trade-off, namely into (i) the fundamental social welfare level that would arise in a Kaldor-Hicks economy with lump-sum transfers, (ii) a correction term that accounts for the social cost of inequality à la Atkinson (Atkinson, A. B. 1970. “On the Measurement of Inequality.” Journal of Economic Theory 2 (3): 244–63) or Sen (Sen, A. 1970. Collective Choice and Social Welfare. Harvard University Press), and (iii) a correction term for the social cost of distortionary taxation. Our estimations show that the German tax system can be well approximated by the imposed tax schedule and that the reform implied a fall in the degree of tax progressivity. Under the baseline calibration, the numerical analysis yields the following results: First, the main driver of growth in social welfare from 1998 to 2007 was fundamental social welfare. Second, the counterfactual analysis shows that the reform resulted in an annual average income growth of 0.62 % and an increase in income inequality of 0.32 %, indicating an only modest increase in social welfare of 0.07 %. Third, the actual tax progression converged to its social welfare maximizing level.