It’s children with parents who can least afford high-quality care who benefit most from it, research has found. That is because affluent children have better alternatives. For well-off children, some studies have linked day care, especially low-quality care early in life, to achievement and behavior problems.
A powerful new study — which demonstrated long-term results by following children from birth until age 35 — found that high-quality care during the earliest years can influence whether both mothers and children born into disadvantage lead more successful lives. The study was led by James J. Heckman, a Nobel laureate economist at the University of Chicago.
“They’re engaged more in the work force, they’re now active participants of society, they’re more educated, they have higher skills,” Mr. Heckman said. “So what we’ve done is promoted mobility across generations.”
The study analyzed two well-known experimental programs in North Carolina, which offered free, full-time care to low-income children age 8 weeks to 5 years, most of whom were black and lived with a single mother. The children in the control group were at home or in lower-quality programs.
The mothers of those in the experimental program earned more when the children were in preschool, and the difference was still there two decades later.
When the boys reached age 30, they earned an average of $19,800 more a year than those in the control group and had half a year more education. (The small sample size — 37 boys in the programs who stayed in the study — means the difference was not very precisely estimated.) When the girls reached 30, they had two more years of education and earned about $2,500 more, the study found.
In their mid-30s, men who attended the program were 33 percent less likely to be drug users, had fewer misdemeanor arrests and were less likely to have high blood pressure.
The conclusion that boys benefited more than girls meshes with other research findings that boys are more sensitive to disadvantage and responsive to intervention.
The program was expensive — $18,514 per student a year — but after calculating effects like the cost to society of unemployment, crime and poor health, the researchers concluded that it returned $7.30 for every dollar spent. In addition to Mr. Heckman, the researchers were Jorge Luis García of the University of Chicago and Duncan Ermini Leaf and María José Prados of the University of Southern California.
High-quality preschool showed multigenerational benefits in another new study, which traced nearly one million children in Denmark until old age. Children who attended the high-quality programs had slightly more years of schooling and an increased…