La composizione familiare e l�imposta sul reddito delle persone fisiche: un�analisi degli effetti redistributivi e alcune considerazioni sul benessere sociale

The paper provides an evaluation of the redistribution effects stemming from the changes to the personal income tax introduced in the last decade. The analysis confirms that between 1989 and 2001 the net average tax rate increased for all taxpayers and, above all, for one-earner couples. The reason is twofold: a) the progressivity of the tax makes larger the burden on these households of changes in income brackets and tax rates; b) the absence of dependent relatives does not allow the compensation of higher taxes with increased tax credits. However, these higher taxes are associated with a distribution of the tax burden that favours low income households with a high number of components, thanks to changes in tax credits. Concerning welfare effects, the results of the analysis are controversial. The net income distribution in 2001 dominates in Lorenz sense that of 1989 if the entire population is considered, if one-earner or two-earner households are separately taken into account, if the population is decomposed on the basis of the number of components in the family. The generalised Lorenz curves show that all one-earner and two-earner households in the lowest part of the income distribution have benefited from the changes in Irpef. The sequential stochastic dominance allows verifying that social welfare has increased for all one-earner households but the singles and has diminished for two-earner households.