Great news for families at The New Century School—a major new study has confirmed what many of us have long believed: Montessori education delivers real, measurable benefits for young learners. And those benefits keep growing over time.
While the study results came directly from “A national randomized controlled trial of the impact of public Montessori preschool at the end of kindergarten,” the photos of children occupied with Montessori materials came from TNCS primary classrooms!
Scientific Observation: Montessori Method
Before diving into the exciting new research, it’s worth remembering the remarkable origins of Montessori education. Dr. Maria Montessori began her work in 1907, experimenting first with atypically developing children and then with low-income children. Working collaboratively, she developed what she called “Scientific Pedagogy”—what we have come to know as the “Montessori Method.”
Her approach was revolutionary: classrooms that group children in 3-year age spans (e.g., 3 to 6), where older children serve as role models and help younger ones. The teacher provides individual and small-group lessons, but learning stems largely from freely chosen interactions with a curated set of hands-on materials. Dr. Montessori’s training conveyed not just lessons on how to present materials, but aimed to instill in teachers “a profound respect for the developmental process and the interconnectedness of all life.”
Today, Montessori education is the longest-running and most common “alternative” pedagogy, with more than 16,000 schools worldwide—including more than 600 public Montessori programs in the United States.
What Makes This Study Special?
This isn’t just another small-scale education study. Published in the prestigious journal PNAS (Proceedings of the National Academy of Sciences) in October 2025, this research followed 588 children across 24 public Montessori schools nationwide from age 3 through the end of kindergarten. Lead researcher Angeline Lillard, MD, from the University of Virginia and her team used the gold standard of educational research: randomized-controlled trials (RCTs), comparing children who attended Montessori schools with those who did not.
Impressive (but Not Surprising) Results
The researchers found that, by the end of kindergarten, Montessori-educated children showed significantly better outcomes in several key areas:
- Reading skills
- Executive function
- Short-term memory
- Social understanding
Let’s dig deeper!
Reading Skills: A Standout Finding
The reading results were particularly striking—with effect sizes approaching a third of a standard deviation. To put this in perspective, the researchers estimate that “a child in a traditional program who performed at the median in reading…would have performed at the 62nd percentile [at] a Montessori study school.”
This finding is especially significant because it has now been replicated across all four recent RCTs examining public Montessori preschool. As the researchers note, compared to children in other programs, “children who entered Montessori at PK3 read at a higher level not in PK3 or PK4, but at the end of kindergarten.”
Why does Montessori produce such strong reading outcomes? The researchers point to alignment with the science of reading: “The methods Montessori uses to teach reading—e.g., beginning with writing, emphasizing phonics—align with the science of reading, perhaps explaining this finding.”
This is particularly important given that reading performance is declining nationwide in U.S. children. Because early reading skill predicts later reading success, these kindergarten gains could have lasting implications for your child’s academic future.
Executive Function: Building Mental Control
Children in Montessori programs performed significantly better on the Head-Toes-Knees-Shoulders (HTKS) test, which measures executive function, what the researchers call “mental control” skills. These are the abilities that help children focus attention, plan ahead, manage tasks, and control impulses.
The researchers emphasize that “higher executive function predicts more positive outcomes in school…and beyond.” Studies have shown that strong executive function in childhood predicts better financial status, health outcomes, and even reduced criminal activity in adulthood.
A child at the median for executive function in a traditional program would perform at the 60th percentile if they had attended Montessori. Better executive function among Montessori students is consistently observed across research studies, likely because the Montessori approach inherently builds these skills through child-directed learning, concentration on chosen activities, and self-regulation.
Short-Term Memory: Foundation for Learning
Montessori students performed significantly better on Forward Digit Span tasks, demonstrating more developed short-term memory. The researchers explain that “memory span is a component of working memory, which also involves manipulating information held in mind.”
Working memory is crucial for learning—it’s what allows children to hold instructions in mind, follow multi-step directions, and process information. While the study also tested backward digit span (which requires manipulating information, not just holding it), results still favored Montessori children, suggesting broad memory benefits.
To understand the impact: a child at the median on memory tasks in a traditional program would reach the 62nd percentile with Montessori education.
Social Understanding: Reading Minds and Hearts
Perhaps one of the most heartwarming findings involves theory of mind, the ability to understand that other people have their own thoughts, feelings, and perspectives different from one’s own. Montessori students performed significantly better on the Theory of Mind Scale, and “theory of mind…predicts social competence.”
This makes intuitive sense in Montessori classrooms, where children of different ages work together, older children mentor younger ones, and students must navigate a complex social environment with freedom and responsibility. A child at the 50th percentile in social understanding would move to the 59th percentile with Montessori education.
Math: Positive Trends
While math results showed smaller effects that just missed statistical significance, Montessori students still did somewhat better. A child at the median in math would be at the 57th percentile had they attended Montessori. Math advantages associated with Montessori preschool appear less consistently across studies than reading advantages, but this positive trend is encouraging.
Putting It All Together
As the researchers note, these intention-to-treat effect sizes “exceeded a fifth of a standard deviation, considered large in field-based school research.” Even more impressively, when looking only at children who actually attended Montessori (complier average causal effect analysis), the effect sizes were 77% to 123% larger—meaning even stronger benefits for children who remained in Montessori programs.
The researchers emphasize an important point: “Multiplied across hundreds of thousands of children, such impacts would be very meaningful.” These aren’t just statistics—they represent real advantages in reading, thinking, remembering, and understanding others that your children are developing every day at TNCS.
As the researchers note, these intention-to-treat effect sizes exceeded a fifth of a standard deviation, considered large in field-based school research.
Why Kindergarten Matters
Here’s what makes these findings particularly exciting: most preschool studies show benefits that disappear by kindergarten. This study found the opposite pattern. The researchers observed that “this contrasts sharply with the more typical finding, where impacts of preschool are observed immediately following the program but disappear by the end of kindergarten.”
The study examined why this might be happening, exploring several possibilities including Montessori’s unique approach to multi-age classrooms, peer learning, and child-directed education with hands-on materials.
What the Experts Say
The study’s significance section puts it beautifully: “Given the impact and lower cost, Montessori might be considered by districts implementing preschool programs for 3-year-olds.”
Dr. Lillard and her colleagues note that their findings are especially meaningful because this was a real-world study of “business-as-usual” Montessori programs, not specially designed research interventions. The 24 schools varied in their implementation but all met basic Montessori criteria.
For TNCS families, this research offers powerful validation of your educational choice. You’re not just following a philosophy—you’re investing in an approach backed by rigorous scientific evidence showing concrete benefits for your child’s cognitive development, reading skills, and social understanding.
The researchers emphasize that “Montessori is an alternative type of preschool program that bridges this dichotomy, offering academic material without whole class instruction, and with several features of play, including free choice, discovery, hands-on materials, and self-evaluation.”
As we navigate the important early years of education, it’s reassuring to know that the Montessori approach at schools like TNCS isn’t just working—it’s working better and longer than many alternatives.
It’s important to note that the study examined public Montessori schools that children entered lotteries to earn spots in. The results are extrapolatable, if not conservative by comparison, to private institutions.











