AMERICA HAS fewer of its three- and four-year-old children in pre-school than other rich nations. But it is beginning to catch up. Between 2002 and 2017, the proportion of four-year-olds enrolled in state pre-kindergarten programmes rose from 14% to 33%. And a big, bipartisan push is underway to get more children into education before they start school. Three Republican-leaning states—Georgia, Florida and Oklahoma—have introduced universal pre-kindergarten. Several contenders for the Democratic presidential nomination, including Joe Biden, Bernie Sanders and Elizabeth Warren, boast universal pre-school policies in their campaigns.
Analyses of large-scale pre-school programmes in the last few years have often been disappointing. But the potential value of pre-school has become clear as participants in long-run studies have grown older. Two new papers look at the long-term effects of perhaps the best known of these, a 1960s-era pilot programme, on both the former pre-schoolers and their children.
Between 1962 and 1965, 128 African-American children from the Perry Elementary School district in Ypsilanti, Michigan were enrolled in an experiment. After being sorted into two groups with similar IQs, gender balance, and socio-economic backgrounds, a coin toss selected one of the groups to receive two-and-a-half hours of pre-school education each weekday for the two years before they entered primary school. They also received an hour-and-a-half of home visits a week from Perry Elementary teachers.
Since then, the participants have been repeatedly surveyed; most recently, most of them were interviewed at the age of 55. James Heckman and Ganesh Karapakula, economists, have examined the long-gathered results in two new papers, using techniques designed to factor in the experiment’s small size, flaws in the randomisation process and missing survey responses. The researchers found that the pre-schooled kids—and in particular the boys—have had considerably different lives as a result.
The pre-schooled group, they found, had about half the average number of violent felony convictions as the control group. Males in that group spent an average of 27 days in jail between the ages of 20 and 50 compared to 136 days for boys in the control group. They also had more success in employment, increased earnings in mid-adulthood and better health. Perry Pre-school Project boys are significantly more likely to have been in stable marital relationships. And the effects appear to persist across generations: the children of beneficiaries have fewer school suspensions, higher levels of education and employment and lower levels of criminal activity.
Another pre-school experiment that has been followed up over years, the Abecedarian Project in North Carolina, which divided 111 children into a test and control group, suggests similar results. Both programmes were expensive, small and run by committed teams, involving a greater level of intervention than the large-scale pre-kindergarten programs being rolled out today. The home visits may have made a particular difference. The researchers report suggestive evidence that the Perry project had some of its biggest effects outside school. Male participants interviewed in their 50s were far less likely to report having been verbally abused by an adult when they were children, having felt neglected, or having been abducted by one parent to hide from another.
Large-scale pre-school progammes do not compare well to these small experiments. While there is widespread research evidence suggesting that pre-schooling yields immediate learning gains, these fade over time. Researchers studying children randomly assigned to the Tennessee Voluntary Pre-kindergarten Programme, for example, found that while participants performed better on a battery of achievement tests at the end, the achievement gap subsequently reversed. And analysis of the rollout of universal pre-Kindergarten in Georgia suggests that there were no significant changes in test scores at fourth grade (around the age of 9-10) among those exposed to the programme compared to similar students from other states where it was was not rolled out.
Some studies do suggest more positive results for disadvantaged subgroups.Results from a pre-school programme in Texas found improvements for low-income students and those who were not proficient in English. The first national randomised evaluation of the Head Start programme, which gives matching grants to states providing early education, health care and nutrition services to children as well as training in parenting, found it made a great difference to cognitive achievement during pre-school. That benefit faded, but it persisted up until first grade for a subsample of Spanish speakers.
All of this suggests pre-school programmes are difficult to deliver effectively to thousands rather than tens of children. The design of such programmes is also important. Elizabeth Cascio, an economist from Dartmouth College, used the nationally representative Early Childhood Longitudinal Study of children born in 2001 to study the impact of different pre-school programmess across America. She found that universal programmes can improve the reading ability of four-year-olds from low-income families, while means-tested programmes have no impact. This, she suggests, may be because universal programmes are higher-quality and more rigorous academically.
The big and sustained effects of the Perry programme suggest that intergenerational inequality can be permanently reduced by early childhood interventions. The priority for policy makers is to figure out how that can be achieved—at scale.