In this report, we evaluate major federal tax expenditures. We distinguish between tax expenditures that are effectively spending programs and those that are departures from a comprehensive income tax but are not essentially spending substitutes. Most major tax expenditures have some policy justification but could be redesigned to better promote policy goals for the same or lower cost. Many smaller tax expenditures that provide special benefits to selected industries or individuals, however, are more difficult to justify on policy grounds. We list these at the end of the report.