The purpose of this project is to assess the budgetary and distributional impact of reforming tax expenditures (e.g., allowances, exemptions, tax credits, etc) which constitute an important amount of forgone government revenue. The approach consists in comparing the tax-benefit system in place with a benchmark tax system without tax expenditures for pensions, housing, education and health. The project covers all Member States and focuses on health, pension, housing and education tax expenditures.