Massive national study shows public Montessori improves outcomes, reduces costs
David Ayer Posted On October 23, 2025 
A $3M, 3-year randomized study of children in public Montessori programs found significant positive impacts in reading, short-term memory, executive function, and social understanding, while costing districts $13,127 less per child over a three year period.
The study, led by Angeline S. Lillard at the University of Virginia followed 588 three to six year old children entered in lotteries at 24 public Montessori programs in 8 U.S. states and the District of Columbia. The 242 children admitted to Montessori programs were compared with children whose families who chose Montessori but did not get in, to eliminate potential selection bias. Children in both groups were followed and evaluated each year, and the differences between the groups did not emerge until after the third, “kindergarten” year.
This new study is important for several reasons:
- Size and scope: This is by far the largest, most comprehensive study of Montessori, public or private,undertaken to date. The research was partially funded by a U.S. Department of Education Institute of Education Science (IES) grant to the American Institutes for Research (AIR).
- Randomized controlled trial (RCT) model: Children of families who sought out Montessori were randomly assigned to Montessori or non-Montessori classroom, so the effect of parental preference was reduced or eliminated.
- Broad sample: The study analyzed Montessori programs across a range of implementations and geographic regions.
- Persistent and dosage-related effects: Other preschool studies have found that effects of preschool “fade out” by kindergarten, but this study showed the opposite: effects accumulated through the first two years of Montessori and were strongest in kindergarten.
- The effects themselves: Reading, short-term memory, executive function, and social understanding are all important skills which predict future success in school and life outcomes.
- Costs: Higher child-to-adult ratios in Montessori programs more than made up for costs of training and materials, saving districts an estimated $13,127 less per child over a three year period.
MontessoriPublic has been following this story since 2018. You can read more here:
- $3.3 Million Federally Funded Montessori Research Study (2018)
- Montessori research update: COVID-19 edition (2020)
The Montessori Census (a national database of Montessori schools operated by the National Center for Montessori in the Public Sector, which also publishes MontessoriPubic) supported this research by helping to identify publicly funded programs with lottery admission at three years old.
David worked in private Montessori for more than twenty years as a parent, three-to-six year-old and adolescent teacher, administrator, writer, speaker, and advocate. In 2016 he began working with the National Center for Montessori in the Public Sector. David lives in Portland, Oregon.
