Somewhere between the tour and the application, a fair question shows up. Every school says its approach works. Is there real evidence for Montessori, or is it simply a calmer-looking classroom?
It is the right question, especially if you are weighing Montessori against a school you already know. The good news is that Montessori has been studied carefully. Some of the strongest studies compare children who won a place by lottery with children who applied and did not.
We are a Montessori school whose Primary and Elementary teachers are AMI-trained, so these studies describe the kind of classroom we run. Here are four worth knowing, what each found, and what it means when you are choosing a school. Angeline Lillard led three of them and co-wrote the fourth.
A review of 32 studies found a modest, real advantage
In 2023, a team of researchers pulled together the evidence from many separate studies of Montessori education. Their systematic review in Campbell Systematic Reviews combined 32 studies and 204 measured effects. On average, Montessori students did better on academic outcomes by about a quarter of a standard deviation, and on nonacademic outcomes by about a third. The review rated the evidence for some of those nonacademic outcomes as lower in quality.
What that means for you: the effect is modest and positive, and it was found across many studies. It is not a promise about any one child. It does tell you that choosing Montessori is a choice the evidence supports, not a leap of faith.
A lottery study followed children from three to six
The hardest problem in education research is that families who choose a school may differ from families who don't. A lottery solves that. In a 2017 study in Frontiers in Psychology, Angeline Lillard and colleagues followed 141 children who applied to two public Montessori schools in Hartford, Connecticut. Some won a place by lottery, and some went to other schools. Each child was tested up to four times over three years, from about age three to six.
The two groups started out at similar levels. Over the three years, the Montessori children gained more in academic achievement, in understanding what other people think, and in mastery orientation, a liking for challenging tasks. There were no clear differences in creativity or social problem solving. The study also found that family income predicted achievement less strongly among the Montessori children than among the others.
What that means for you: these children had the full three years, through age six. That is the span a Primary classroom covers, and in our Primary, the final year is the kindergarten year.
A national trial found the difference in kindergarten
In 2025, a national randomized controlled trial in PNAS followed 588 children who entered admission lotteries at 24 public Montessori programs. At the end of the first and second preschool years, the study found no notable differences. By the end of kindergarten, the children who had won a Montessori place showed higher reading ability, stronger executive function and short-term memory, and better social understanding.
What that means for you: in this study, the advantage appeared in the third year. If your child could move to TK or public kindergarten at four or five, that is an option worth weighing. This finding belongs in the weighing too. Our Primary page answers why a family might stay for the final Primary year.
How faithfully a school follows Montessori seems to matter
Not every classroom with Montessori on the sign works the same way. A 2012 study in the Journal of School Psychology compared three groups of preschool children. Some were in classic, high-fidelity Montessori classrooms, some in Montessori classrooms that added conventional activities, and some in conventional programs. Over a school year, the children in the classic Montessori classrooms gained more.
What that means for you: the name alone tells you little, because anyone can call a school Montessori. Look at what happens in the room. Ask where the lead teachers trained, whether the shelves hold a full set of Montessori materials, and how long children work without interruption. In our Elementary, the morning work period runs three hours. Our guide to choosing a school lists the questions to take on any tour, and Why Montessori explains how to judge whether a school is authentic.
What the research can't tell you
Every one of these studies reports what happened on average, across many children in many classrooms. None can tell you how your child will do in a particular room, with particular adults, this year. That part of the decision is yours, and it is best made in person.
The studies do point at what to look for when you visit. They suggest looking for trained guides, a full set of materials, long stretches of uninterrupted work, and time for a child to complete the cycle. You can check each of those with your own eyes.
See the evidence in a real classroom
The research describes conditions. A tour lets you see whether a school has them. Our first tour is for adults only, so you can watch a morning work period and ask the guides every question you brought.
Schedule a tour and judge the conditions for yourself. If you would like to read further first, our reading list includes Angeline Lillard's book Montessori: The Science Behind the Genius.
Questions parents ask about Montessori research
Is there real research behind Montessori?
Yes. A 2023 systematic review combined 32 studies and found modest positive effects on both academic and nonacademic outcomes. Two of the strongest studies used admission lotteries, comparing children who won a Montessori place with children who applied and did not. A 2017 study followed children from three to six, and a 2025 national trial followed 588 children through the end of kindergarten.
Do Montessori children do as well academically?
In the studies above, they did better on average. The 2023 review found an academic advantage of about a quarter of a standard deviation. The 2025 national trial found higher reading ability at the end of kindergarten, though no notable differences at the end of the two preschool years before it. These are averages across many children, not a promise about one child.
Does it matter which Montessori school we choose?
It seems to. A 2012 study found that children in classic, high-fidelity Montessori classrooms gained more over a school year than children in Montessori classrooms that added conventional activities. Because anyone can use the name, ask where the lead teachers trained, what is on the shelves, and how long children work without interruption. South Coast Montessori's Primary and Elementary teachers are AMI-trained.
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