For six months in 2021, the expanded Child Tax Credit provided monthly payments—in effect, an unconditional cash benefit—to most families with children. Although the expanded CTC expired, the debate about renewing it or enacting a similar policy continues. This analysis provides insight into the link between income and changes in childhood test scores and behavior. The data collected serves as an input into the Social Genome Model version 2.1 (SGM), a model jointly developed by the Urban Institute, Brookings Institution, and Child Trends to complement the growing literature around the short-term effects of the CTC on poverty and food insecurity by assessing the long-term impacts of cash payments to families with children. This analysis shows that children from families with low income who would receive the average annual increase from the CTC if the 2021 expansions were made permanent have higher birth weights, higher achievement in math and reading, and improved behavior. As a result of this, at age 30, children from these families are more likely to graduate from high school and college and earn between 7 and 12 percent more annually.