The earned income tax credit provides substantial assistance to low- and moderate-income workers. Benefits tilt heavily to families with children. Prompted in part by the success of the credit and in part by shortcomings in the credit, policymakers, advocates, and analysts have offered up reform proposals. In this report, we describe the credit’s current effects and then analyze the credit’s basic elements (its eligibility requirements, design, timing, administration, and effects on other programs including State EITCs and transfer programs) to help guide thinking on these potential reforms.