The programs focused on early-language, motor, and cognitive development, as well as social-emotional skills like the ability to concentrate on a project. The curriculum emphasized active experiences such as play, and was tailored to each child’s abilities.

Babies, who were referred by hospitals and local agencies, started the program early, after about 8 weeks of life, and attended 50 weeks a year from 7:45 a.m. to about 5:30 p.m. five days each week, meaning the centers effectively doubled as daycare. Right now, childcare and early-childhood education are often studied separately, Jorge Luis Garcia, a research assistant at the center Heckman runs, said during a phone interview. But as the number of single mothers rises, he said, and the need for childcare increases, it’s increasingly important to consider how quality childcare that begins at birth and also educates children could positively influence women’s participation in the workforce and help their families over time.

Researchers checked in with participants regularly through age 35 to see how they were faring. They looked not only at IQ and education level, but also at their health, their income, their criminal records, their overall quality of life, and whether their participation in the program increased their mothers’ earnings (an important factor because most of the children grew up with single mothers).

For every dollar spent on early-childhood education, the researchers found a benefit of about $6.30. And crucially, they found benefits across the board, from health to education, with some variation between men and women. (They acknowledge that they are limited by the fact that they cannot measure the potential benefits families derive when parents stay home and the fact that women are more likely to stay home.)

Ultimately, the team found that employment at age 30 increased between 7 and 13 points for women who participated in the programs, and between 11 and 18 points for men, compared to people who attended a lower-quality alternative or stayed at home. The researchers found that placement in a low-quality alternative was more damaging for boys than for girls. Men also seemed to derive more physical health benefits, while women seemed to benefit more across a range of mental-health measures.

Unlike most other studies on the topic, the researchers predicted the lifetime health benefits of the programs. “We’re measuring something that hasn’t been measured before,” Heckman said. To do that, his team relied on a model developed by Dana Goldman, the director of the Schaeffer Center for Health Policy and Economics at USC.

Many people in the research community shy away from trying to make such predictions, Goldman said during a phone conversation, but he thinks difficult questions about long-term outcomes are “the most important.” People who want to build bridges or other infrastructure know they need to look at returns 50 or 100 years in the future to make an intelligent investment, he said. Yet when it comes to kids and developing policies and programs around them, he noted, most people only look a decade out because of supposed data limitations. It “doesn’t make any fiscal sense,” he continued.