Montessori Delivers Stronger and More Enduring Early Learning Outcomes — at Lower Cost

A new national study offers strong evidence that public Montessori preschool supports lasting gains for children—while costing less to deliver than traditional programs.

Researchers from the University of Virginia and the American Institutes for Research followed 588 children from age three through the end of kindergarten who entered lotteries for seats at 24 public Montessori schools across the country. Because seats were assigned by random lottery and the programs were existing, “business-as-usual” public Montessori classrooms rather than researcher-designed interventions, the findings provide unusually strong and realistic evidence of Montessori’s impact.

Key Findings

Stronger outcomes at the end of kindergarten

Children offered a Montessori seat showed higher scores in reading, memory, executive function, and social understanding compared with peers in other programs. These gains grew over time—appearing most clearly at the end of kindergarten, rather than fading as is often seen in other preschool studies.

Reading success

Montessori students read at a higher level by kindergarten, with average gains roughly a third of a standard deviation—large by education-research standards. This may be explained by Montessori methods used to teach reading – beginning with writing, emphasizing phonics, and aligning with the science of reading. 

Lower cost for districts

Over three years (ages 3–6), public Montessori programs cost about $13,000 less per child than traditional preschool models. Montessori classrooms are designed for larger child-to-teacher ratios—typically 25–30 children with one lead guide and one or two assistants—because the approach centers on independent work, peer learning, and freely chosen hands-on activities rather than whole-group instruction. These intentional design choices support mixed-age learning—central to Montessori environments—and reduce staffing costs without compromising quality.

Sustained impact

Unlike most preschool programs where early advantages fade, Montessori gains strengthened through kindergarten, echoing results from smaller prior studies. Researchers suggest this may be because Montessori classrooms provide continuity across multiple years, peer learning within mixed-age groups—including opportunities for older children to teach and mentor younger children, a process shown to reinforce learning for both—and self-directed, hands-on work that allows skills to deepen gradually rather than peak and fade.

Why This Matters

The study demonstrates that a well-implemented Montessori model can raise achievement, strengthen critical thinking and self-regulation, and do so at lower cost. It suggests that districts seeking to expand early learning access for three-year-olds can consider Montessori as a cost-effective, evidence-based approach that supports both academic and social growth.

Reference

Lillard, A. S. et al. (2025). A National Randomized Controlled Trial of the Impact of Public Montessori Preschool at the End of Kindergarten. Proceedings of the National Academy of Sciences (PNAS). 

Read the full study » https://www.pnas.org/doi/epdf/10.1073/pnas.2506130122 

Interested in Expanding Access to Public Montessori?

This study reinforces what Wildflower Teacher Leaders see every day: public Montessori can deliver strong outcomes while expanding access for families.

Wildflower now includes 10 public Montessori preschools offering free, high-quality early learning—and we’re supporting new leaders to open more.

Explore open public charter opportunities at 🔗 wildflowerschools.org/current-opportunities.