A tax discrepancy coefficient resulting from tax evasion or tax expenditures

Tax evasion and tax expenditures introduce discrepancies between taxpayers. In this paper, a tax discrepancy coefficient has been worked out in order to establish, given a constant tax yield, what bigger or smaller amounts taxpayers would have to pay if tax evasion or tax expenditures were completely eliminated. After the definition of the coefficients these are calculated for individual income tax returns in Belgium. Similar coefficients can be established for other types of taxation, such as inheritance tax, corporate income tax or even sales tax (e.g. V.A.T.).