Income taxes, on the other hand, usually do not affect social-security-contribution liabilities. In the results reported here, the redistributive effect of social security contributions is therefore assessed against before-tax incomes, while the redistribution achieved by income taxes is determined relative to before-tax incomes minus social contributions. Following the definitions spelled out in Box 1, “social contribution” include only that part that is formally paid by households while employer contributions and payroll taxes are not considered.