From the Summary: "The federal individual income tax is structured so that the poor owe little or no income tax. In addition, the federal individual income tax (hereinafter referred to simply as the 'income tax code' or 'income tax') increases the disposable income of many poor families via refundable tax credits--primarily the earned income tax credit (EITC) and the refundable portion of the child tax credit, referred to as the 'additional child tax credit' (ACTC). These credits are explicitly designed to benefit low-income families with workers and children and can significantly boost families' disposable income, lifting many of these families above the poverty line."
CRS Report for Congress, R45971
Congressional Research Service: https://crsreports.congress.gov/