Full-day pre-K beats half-day, first-of-its-kind study shows

In a first-of-its-kind study, researchers working in a school district near Denver have examined the impacts of enrolling children in full- versus half-day preschool programs.

The results show that doubling the time that kids spend in prekindergarten classes could have big benefits for their learning. The research team, led by CU Boulder’s Allison Atteberry, found that the extra school hours improved how children performed in assessments of vocabulary, literacy, math and more.

It’s not clear whether the positive effects will be sustained as the students continue their education—the researchers only looked at kids’ progress over their pre-K year.

But the study, published in the journal Educational Evaluation and Policy Analysis, adds to a growing body of evidence suggesting that experiences early on in life may have huge implications for a child’s academic growth. That’s likely because of how quickly children’s brains evolve, Atteberry said.

“Even a month in the life of a young child may represent a huge period in their development,” said Atteberry, an assistant professor in the CU Boulder School of Education. “At the same time, this is a period when families are making very different choices about childcare and have different resources to make those choices.”

Many educators and politicians are taking note. Several candidates in 2020 political races have made early-childhood education and care a priority in their campaigns.

Colorado also recently opened the way for all children in the state to attend free full-day kindergarten.

New classrooms

The current study, Atteberry said, came about almost by chance. In 2016, Westminster Public Schools, a district that serves a largely Latino and low-income population in the suburbs of Denver, received funding to open up several full-day pre-K classrooms.

Those new learning spaces, in turn, allowed the district to enroll about half its pre-Kindergarten students in school from 8 a.m.-3 p.m., rather than the usual half day. That set up a natural experiment.

“We have some correlational evidence of the positive effects of early childhood experiences on academic success,” Atteberry said. “What set this study apart is that we were able to do a randomized, controlled trial.”

She explained that parents in Westminster who wanted to enroll their children in pre-K classes had to first sign up for a random lottery. In the first year, about half of the applicants, or more than 110 children, were assigned to full-day classrooms, while the other half attended class for half the day.

Atteberry and her colleagues, who included Daphna Bassok and Vivian Wong from the University of Virginia, then followed the students’ progress throughout the school year.

The differences stacked up: By the end of the year, the full-day students were outperforming their peers in a wide range of measures. Study students, many of whom didn’t grow up speaking English as a first language, showed greater improvement in their English fluency if they were enrolled in a full-day rather than a half-day class.

“This project highlights not only the importance of early-childhood education for parents but also the ability of a high-quality program to show extended results for our youngest learners,” said Mathieu Aubuchon, the director of elementary education for Westminster Public Schools.

Regular naps

Why more time spent in school delivers such benefits is an open question, Atteberry said.

“Some people might explain the benefit by saying, ‘well, you’re doubling the dosage of math and reading time,’” she said. “But it may not be that simple.”

Students who went to school for the whole day, she said, also received school lunches and had mandatory nap time. The four-year-olds who went home before noon, however, didn’t necessarily have that same access to regular sleep and meals.

Whatever the cause, the researchers are currently tracking if the learning boosts last as the Westminster students graduate from Kindergarten and head off to elementary school.

“We’ll be looking at how long these effects persist,” Atteberry said. “Sometimes in early-childhood research, we see a big initial effect, but by 2nd or 3rd grade, it fades away.”

The results might also change depending on the district.

“Our findings don’t necessarily mean that a school district with very different demographics should make the choice to go to full-day pre-K,” Atteberry said. “What if you took that large amount of money and invested in a different early-childhood resource?”

Still, she said studies like this one could help to guide policy-makers across the U.S. as they decide how best to help young children begin their education on the right foot.

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