Family Structure Tops Race, Income as School Success Predictor

Some universities have responded by loosening or eliminating standardized test requirements. More than 2,000 colleges and universities, including Ivy League schools and large public systems, now make SAT and ACT scores optional. Harvard reported that 60 percent of its undergraduate grades in the 2024-25 year were As, up from about 25 percent two decades earlier. The University of Michigan’s College of Literature, Science and the Arts, starting in fall 2027, will give no grades to first-term freshmen, citing a mental-health crisis.

Wilcox sees the grade-inflation trend as a reaction that avoids the underlying issue. “Raising children in a stable married family is incredibly helpful to kids,” he said. He argues that public awareness of the family-structure effect would do more than changing assessment policies.

The report also points to a policy barrier the researchers call the “marriage penalty.” When two individuals with similar incomes marry, their combined household income can push them above thresholds for welfare benefits, including subsidized housing. Federal data cited by IFS shows that only 3 percent of subsidized housing units serve two adults with children; 30 percent go to a female head with children.

Rep. Glenn Grothman, a Wisconsin Republican, said in a statement that “marriage penalties are one of the most damaging and misguided features of the federal welfare system” and that they “trap parents and children in long-term dependency.”

Wilcox stopped short of a blanket prescription. “Not every couple who are having kids should get married and not every couple who are married should stay married,” he said. “But it’s important when it comes to having and raising kids to do what you can to be married and to stay married.”

The report notes that the proportion of American children living in married families bottomed out at 64 percent in 2012 and has ticked up to 66 percent as of 2024.