Thilo Schaefer

Documentation FiFoSiM: Integrated Tax Benefit Microsimulation and CGE Model

This documentation describes FiFoSiM, the integrated tax benefit microsimulation and CGE model of the Center of Public Economics at the University of Cologne. FiFoSiM consists of three main parts. The first part is a static tax benefit microsimulation module. The second part adds a behavioural component to the model: an econometricaly estimated labour supply model. The third module is a CGE model which allows the user of FiFoSiM to assess the global economic e¤ects of policy measures. Two specific features distinguish FiFoSiM from other tax benefit models. First, the simultaneous use of two databases for the tax benefit module and second, the linkage of the tax benefit model to a CGE model.

Does Tax Simplification Yield More Equity and Efficiency? An Empirical Analysis for Germany

This paper investigates the impact of tax simplification on various indicators of the efficiency of the tax system and on the distribution of income. The analysis is based on a simulation model (FiFoSiM) using German income tax and household survey microdata. We model tax simplification as the abolition of a set of deductions from the tax base included in the German income tax system. We find that this form of tax base simplification leads to a reduction in the use of professional tax advice, a more equitable income distribution and an increase in tax revenue. If these measures are combined with a reduction of income tax rates to preserve revenue neutrality, the effects depend on the type of rate schedule adjustment. The combination with a flat rate tax implies redistribution in favour of very high incomes, and an overall increase in income inequality. Efficiency effects in terms of changes in marginal tax rates and labor supply effects are mixed. The combination with a rate schedule adjustment which preserves the directly progressive rate schedule yields a tax reform which reduces the inequality of after tax incomes. We conclude that tax simplification may improve the efficiency of the tax system without increasing inequality of after tax income.

Measuring Richness and Poverty - A Micro Data Application to Germany and the EU-15

In this paper, we define a new class of richness measures. In contrast to the often used head-count, these new measures are sensitive to changes in rich persons income and therefore allow for a more sophisticated analysis of richness. We demonstrate the application of these new measures to analyse the development of poverty and richness over time in Germany, to compare Germany to the other EU-15 countries and to investigate the impact of tax reforms on poverty and richness. The latter analysis is based on micro data provided by the simulation model FiFoSiM using German income tax and household survey micro data. We show that it partly depends on the measure whether the development of richness in Germany is increasing or decreasing. The cross country analysis yields several groups of countries according to their values of poverty and richness indices. The new richness measures show that the effects of flat tax reform scenarios depend on the reform parameters. Using these examples, we show the importance of taking into account the dimension of changes and not only the number of people beyond a given richness line (headcount). We propose to use the new measures in addition to the headcount index for a more comprehensive analysis of richness.

Is a Flat Tax Politically Feasible in a Grown-Up Welfare State?

The introduction of a flat tax is supposed to have several advantages. Administration and compliance costs are reduced, as well as incentives for tax evasion. Furthermore, positive employment and growth effects are expected. Despite these advantages, a flat rate tax is not very popular in most Western European countries. The most important objection against a flat tax states that a flat rate tax would be inequitable and unfair. The present paper uses a simulation model based on a unique database of German micro data to provide empirical evidence for the analysis of the equity and efficiency effects as indicators for the political feasibility of flat rate tax reforms. Our analysis shows that the selection of the schedule and tax base parameters are crucial for the effects of flat tax reforms in terms of equity and efficiency. A flat rate tax with a higher basic allowance and a higher single rate has less harmful distributional effects than a flat rate tax with low basic allowance and tax rate. Nevertheless, the scenario with the lowest parameter values for basic allowance and tax rate is the only alternative that leads to positive labour supply and significantly positive welfare effects. Both labour supply and static welfare effects, however, are quite small. Although we have derived our results for the case of Germany, we do think that similar patterns would be observed in other countries of Western Europe. If this proves to be correct, it will be hard for flat tax reforms to invade the grown-up welfare states of Old Europe.

How Progressive is Germany? Comparing the Redistributive Effects of Tax Benefit Systems in Europe

When comparing tax benefit systems across Europe, Germany is usually regarded as a country with a high level of taxes and contributions which is often seen as a main challenge for the economic performance of the welfare state. In this paper, we analyse the progressivity and redistribution induced by the tax benefit systems in the EUR-15 countries. We show that the German system as a whole employs only a medium level of redistribution. However, this can be decomposed into a highly progressive income tax system, a highly unequal pre-tax income distribution and regressive social insurance contributions.