When I started running Boston's early childhood program back in 2005, I did what you might expect from a researcher-turned-practitioner: I went into classrooms and watched. What I saw was a wide range of experiences. Sometimes, rooms were joyful and purposeful, with children deep in conversation with one another and with the teacher—building things and asking multiple questions to enhance the group and their own knowledge. Other times, I saw children doing a variety of disconnected activities and passively listening to the teacher in large groups.
It didn't take long to understand that access to a pre-K seat and access to a good pre-K experience are two very different things.
The same pattern showed up in the kindergarten and early elementary classrooms I visited. Rooms were a mixture of rich, collaborative learning, and one-way lessons delivered to passive listeners. There was often little connection between what a child explored in one grade and what awaited them in the next—what happened in pre-K rarely carried into kindergarten, and what happened in kindergarten rarely carried into first grade.
The reality of that observation and available evidence shaped everything we built in Boston. We first rolled out a high-quality curriculum in more than 150 pre-K classrooms across Boston Public Schools and community-based sites, but we quickly saw that the gains of children made in pre-K were fading once they moved into kindergarten and first grade. So, we tried something new: we wrote and aligned a new curriculum, Focus on Early Learning, across kindergarten, first, and second grade, ultimately reaching more than 800 classrooms.
Research confirmed what we observed: children who had consistent, connected experiences from pre-K through the early elementary grades held onto their gains in language and literacy in ways that children in disconnected classrooms did not.
Today, I have the honor of leading a team at the Gates Foundation working to bring these lessons and evidence to partners nationwide. The U.S. has made real progress expanding access to public pre-K—nearly 2.5 million children now attend—but expansion has outpaced quality. Let’s dig into what science tells us about how young children learn, and what it takes to close that gap.
Purposeful play is the work
At 4 and 5 years old, children learn best when they are active, curious, and engaged in meaningful experiences. Language, math, executive function, and social-emotional skills all develop together—and they develop through doing, both independently and in groups. That means being in small groups where children work hands-on with carefully chosen materials, what educators call learning centers.
In Boston, each center was intentionally designed around a bigger topic the class was exploring together, like what makes a community, how shadows and reflections work, or how animals live in their habitats. Teachers receive guidance on how they can adapt these centers to the cultural, linguistic, and personal backgrounds and experiences of the children in their classroom. Children move through these spaces, often in small groups, building knowledge and vocabulary alongside each other. Teachers—following a scope and sequence that ensures every child has access to connect in meaningful ways—check in, ask questions, and help deepen their thinking.
Just like adults learn and grow through collaboration, young children learn as they try and solve problems. And there is a structured curriculum behind it. It just doesn't always look like what we traditionally associate with school.
Whole group activities and direct instruction do have their place in early education classrooms. Teaching foundational literacy and math skills is most efficient in whole groups, but it’s about a balance of teacher-led and child-led activities, with play incorporated intentionally in both. Small groups and center time enhance students’ ability to apply and expand concepts learned in the whole group. It’s a dance between small and whole group—not one or the other.
In 2024, the National Academies of Sciences, Engineering, and Medicine (NASEM) released a landmark consensus report on preschool curriculum quality. This first-of-its-kind report defined what a high-quality early childhood curriculum requires: clear learning progressions across all domains, content that connects to children's lives and experiences, and activities that are engaging, playful, and intentional. The report also found that many programs continue to use curricula that are neither evidence-based nor adaptive to children’s cultural and linguistic backgrounds.
We're starting to see curricula built with these learning progressions in mind. Great First Eight (GF8), developed by a team of early childhood scholars, including Dr. Nell K. Duke, Dr. Marisha Humphries, and Dr. Claire Vallotton, is one example. GF8 is a whole-child curriculum that spans from pre-K to 2nd grade and is designed to strengthen early literacy, math, and other key developmental domains through a play-based, responsive approach.
When people hear "play-based learning," they sometimes picture children doing whatever they want while teachers watch. The evidence points to something different: intentional, teacher-guided play with a balance of teacher- and child-led activities. Children explore concepts through hands-on activities and open-ended inquiry, and teachers actively scaffold that exploration—asking questions, extending thinking, naming what children are learning as they go. Studies consistently show that children in well-designed play-based classrooms achieve equal or better academic outcomes than peers in direct-instruction models, while demonstrating stronger motivation and engagement.
In Boston, we saw this play out in classrooms every day. Our Focus on Early Learning curriculum, now used in states like Massachusetts, Mississippi, and Maine, and cities like Washington, D.C., integrates literacy with science and social studies themes, and weaves play-based routines throughout the day. One of its signature practices, Storytelling, which is based on Vivian Paley’s brilliant work, invites children to compose and act out their own stories. It's joyful and imaginative. It's also one of the most rigorous language development activities a pre-K teacher can do.
The key is intentionality. High-quality instruction requires teachers who deeply understand child development, who plan purposefully, and who know how to follow a child's curiosity while still guiding them toward meaningful learning goals. That's a professional skill—and it's one that needs professional-grade support.
And with the right supports, this kind of rigor and joy is possible in a wide variety of early childhood settings. In Boston, we extended the same curriculum, coaching, and quality standards to community-based classrooms across the city. The same coaches who supported Boston Public Schools (BPS) teachers worked side-by-side with teachers in community-based and family child care sites. We also required community-based teachers to hold a bachelor's degree in early childhood education and paid them the same starting salary as their BPS counterparts. Teacher turnover dropped, classroom quality went up, and it sent a clear message that teaching young children is serious, skilled work.
What this means for the field
Thanks to a lot of meaningful research, we know a great deal about how young children learn. We know what high-quality curriculum looks like, what it requires of teachers, and what it produces for kids. The challenge is translating that knowledge into consistent practice—at scale, and across communities with different resources and needs.
The Gates Foundation is investing more than $90 million over four years to help our partners close the gap between what we know works and what children are experiencing in classrooms. This work centers on three things: helping create and spread high-quality instructional materials, supporting the development of better tools for measuring children's growth, and building and sharing evidence about what works in local communities.
We know what high-quality pre-K looks like. We know what it takes to build it. We know every child deserves access to and benefits from a good pre-K experience. Now comes the hard and necessary work of making it available to every child.