TESTING FOR MARGINAL CHANGES IN INCOME DISTRIBUTIONS WITH LORENZ AND CONCENTRATION CURVES

Asymptotically distribution free statistical tests for comparing absolute and relative Lorenz and concentration curves are provided. The procedures do not require independent samples and can be used to test for marginal changes in income distributions. The tests are illustrated using a large sample of tax returns that have been randomly selected for audit by the Internal Revenue Service. The tests reveal the marginal effects of systematic underreporting of income and tax liabilities on the U.S. income distribution.