One of the most comprehensive studies of California’s multibillion-dollar investments in early education programs provides evidence that the money pays off in academic achievement years later.
Children who enrolled under California’s first transitional kindergarten program, a 2010 law, were 11 months ahead in reading and eight months ahead in math by third and fourth grade compared with children born a few years before the program began, according to a study commissioned by Stanford and conducted by UC Berkeley researchers.
The law, which took effect in 2012, allows a limited number of children with fall birthdays to attend a full year of school before starting kindergarten, known as transitional kindergarten. At the same time, the law changed to allow more to enroll at age 3, when children became eligible for state-funded preschool. Researchers found that this extra early education helped children perform better years later.
The findings come as California enters its second year of offering free transitional kindergarten, or TK, to all 4-year-olds, fully expanding earlier and smaller programs. According to 2025 data, more than half of children at that grade level are enrolled in TK, below national projections. The state has budgeted approximately $4.1 billion for TK in the 2025-26 school year, while also providing an additional $2.8 billion for its state preschool program.
The commitment to investing early in the state’s youngest children goes far beyond elementary school test scores, according to study co-author Rucker Johnson, a professor of public policy at the University of California, Berkeley. This is an opportunity to help children succeed who might otherwise be limited by circumstances beyond their control.
“We call it the search for the missing Einstein,” Luck said. “There are people who have the ability, but without investment they don’t realize that potential.”
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Early opportunity to close the gap
For decades, researchers have shown that children from wealthy families tend to do better in school than their lower-income peers, and that these differences stick with them throughout school.
“Tell me your family’s income in kindergarten, and I’ll tell you where you rank on the test score rankings,” said Austin Rand, a Berkeley researcher and co-author of the study. “This is a tragedy for our society.”
The new study, published by the nonprofit, nonpartisan Learning Policy Institute, shows that preschool and TK can help close this gap. The research was funded by the William T. Grant Foundation, the Heising-Simons Foundation and the Ballmer Group. Philanthropies including Heising-Simons and the Ballmer Group provide some funding for The New York Times’ education coverage.
Researchers tracked 1.6 million children who started kindergarten between 2011 and 2014, comparing the subsequent reading and math scores of children who were exposed to traditional knowledge before kindergarten with those who were not.
The researchers then looked specifically at how much progress came from engaging with traditional knowledge. For low-income children with English-speaking parents, traditional knowledge alone can add an extra seven months of learning in third-grade reading and math.
Children from wealthier families benefit less from traditional knowledge, possibly because they already have access to private kindergartens and other resources.
Overall gains in reading and math reflect the impact of the 2010 law’s changes to preschool and TK programs for children from families of all incomes.
Additionally, children from low-income families who attended both prekindergarten and traditional knowledge classes and whose parents spoke a language other than English made about five times as much progress in fourth-grade math and three times more in reading than children who did not attend public prekindergarten, the study said.
“They are ready to learn”
The research specifically reflects what kindergarten and elementary school teachers are also seeing: high-quality education that starts early provides students with a better foundation.
In Marylou Escobar’s kindergarten classroom at John Muir Elementary School in Glendale, seven of her 20 students are enrolled in transitional kindergarten. The other 13 came from different preschool education backgrounds.
Escobar, who has spent most of her 41-year teaching career in kindergarten, said she immediately saw the difference.
Children who attend TK already know how to sit on the classroom carpet, listen to lectures, and move between activities. They are familiar with holding a pencil and working independently. Escobar could start teaching them letters, syllables and how to put words together.
For some other kids, she’s still teaching the basics of how the classroom works: focusing for five to 10 minutes and pointing up and down on a piece of paper. These are skills that TK students already possess, she said.
“They’re ready to learn, and other kids are getting ready to learn,” Escobar said.
Anna Markowitz, an associate professor of education at UCLA who was not involved in the study, said the findings were alarming and that some studies have found that the academic benefits of preschool fade away over time.
Markowitz said even a month of extra study would have researchers “excited.”
Markowitz said early education is not a “magic bullet.” But this study “proves” that integrating traditional knowledge and pre-school education with the wider school experience can bring lasting benefits.
Johnson, a co-author of the study, describes the results as a multiplier effect, in which each investment in education—pre-K, TK enrollment and higher spending in schools—adds value to the next step.
“You might think of it as addition, like two plus two equals four,” he said. “We found that it could be multiplicative.”
what happens next
California faces challenges in maintaining the quality of its rapidly expanding TK system, including recruiting teachers with training and experience working with young children.
“If this is a brand new grade, that means we have to get the entire teaching staff up to the challenge,” Johnson said.
He hopes to eventually track students into high school and college to see whether their early academic advantages translate into higher graduation rates and college readiness.
“I can imagine that the likelihood of going to college increases, and I can also imagine that the quality of college increases because college readiness is affected by these investments,” Johnson said.
These foundations can start with something as simple as learning to put on a jacket, a common milestone for preschoolers.
It seems that getting ready to go out requires children to remember a few steps, coordinate their movements, and keep trying when things go wrong.
“It’s a multi-step process,” Markowitz said. “If you do it wrong, it can cause physical discomfort, so they’re learning how to overcome that.”
These early skills can help children tackle more complex challenges as they get older, such as learning to read and solving math problems.
“Learning to focus, learning to get excited about trying something new or challenging — and taking those things forward means everything,” Markowitz said.
This article is part of The Times’ early childhood education program, which focuses on the learning and development of California children from birth to age 5. For more information about the program and its philanthropic funders, visit latimes.com/earlyed.