Under the law known as the Tax Cuts and Jobs Act (TCJA), the child tax credit was revised to become available to more lawmakers. Therefore, 2017 provisions expanding the definition of qualifying children and qualifying relatives for the child tax credit must be revisited. Additionally, this expanded definition of dependents under Sec. 152 also affects any taxpayer who qualifies to file as a surviving spouse (according to the U.S. Census Bureau in 2018, there were 844,000 children under 18 living with a widow or widower parent).
Hopkins & Nielsen, Broadened definition of Sec. 152 dependents, Journal of Accountancy
