Coalition for Evidence-Based Policy
@coalition4evidence.bsky.social
The Coalition for Evidence-Based Policy is a nonprofit, nonpartisan organization, whose mission is to tackle major U.S. social problems using rigorous evidence about “what works.” www.evidencebasedpolicy.org
Here's the published study report: pnas.org/doi/10.1073/....
A national randomized controlled trial of the impact of public Montessori preschool at the end of kindergarten | PNAS
Although seminal studies from the early 1960s suggested quality preschool can have
lasting positive effects, agreement is lacking on the efficacy o...
pnas.org
November 24, 2025 at 6:21 PM
Here's the published study report: pnas.org/doi/10.1073/....
Here's our No-Spin report: nospin.evidencebasedpolicy.org/articles/pub....
Public Montessori Preschools | No-Spin Evidence Review
nospin.evidencebasedpolicy.org
November 24, 2025 at 6:21 PM
Here's our No-Spin report: nospin.evidencebasedpolicy.org/articles/pub....
Disclosure: Arnold Ventures, which funds No-Spin Evidence Review, helped fund the kindergarten follow-up of the Montessori study.
November 24, 2025 at 6:21 PM
Disclosure: Arnold Ventures, which funds No-Spin Evidence Review, helped fund the kindergarten follow-up of the Montessori study.
9/ Such high attrition creates “unacceptable levels of potential bias” under recognized standards (WWC) by undermining the treatment-control group equivalence created by randomization.
November 24, 2025 at 6:21 PM
9/ Such high attrition creates “unacceptable levels of potential bias” under recognized standards (WWC) by undermining the treatment-control group equivalence created by randomization.
8/ Additional sample loss at the kindergarten follow-up left roughly 18% of the treatment group and 8% of the control group in the final sample with available outcome data to estimate the program’s impacts.
November 24, 2025 at 6:21 PM
8/ Additional sample loss at the kindergarten follow-up left roughly 18% of the treatment group and 8% of the control group in the final sample with available outcome data to estimate the program’s impacts.
7/ The differential T-C consent rates were likely driven by the fact that most families knew whether or not their child had been admitted to Montessori (i.e., was in the treatment group) when they were asked to consent.
November 24, 2025 at 6:21 PM
7/ The differential T-C consent rates were likely driven by the fact that most families knew whether or not their child had been admitted to Montessori (i.e., was in the treatment group) when they were asked to consent.
6/ But we believe these findings are unreliable due to high sample attrition that differed between the treatment & control group. Specifically - only about 34% of T families & 17% of C families consented to study participation (eg, to have their child's outcome data collected).
November 24, 2025 at 6:21 PM
6/ But we believe these findings are unreliable due to high sample attrition that differed between the treatment & control group. Specifically - only about 34% of T families & 17% of C families consented to study participation (eg, to have their child's outcome data collected).
5/ FINDINGS. Of the 9 prespecified primary outcomes at kindergarten follow-up, the study found sizable, statistically significant positive effects on 4: one measure of early literacy skills & three measures of cognitive skills (standardized effect sizes ranged from 0.22 to 0.30).
November 24, 2025 at 6:21 PM
5/ FINDINGS. Of the 9 prespecified primary outcomes at kindergarten follow-up, the study found sizable, statistically significant positive effects on 4: one measure of early literacy skills & three measures of cognitive skills (standardized effect sizes ranged from 0.22 to 0.30).
4/ STUDY DESIGN. A total of 2,919 children applied to 24 oversubscribed public Montessori schools. The schools used randomized lotteries to determine which children were offered admission (treatment group) or not (control group).
November 24, 2025 at 6:21 PM
4/ STUDY DESIGN. A total of 2,919 children applied to 24 oversubscribed public Montessori schools. The schools used randomized lotteries to determine which children were offered admission (treatment group) or not (control group).
3/ PROGRAM (cont): While teachers provide small group lessons, children learn largely through self-directed use of curated hands-on materials.
November 24, 2025 at 6:21 PM
3/ PROGRAM (cont): While teachers provide small group lessons, children learn largely through self-directed use of curated hands-on materials.
2/ PROGRAM. Montessori is a commonly used “alternative” educational model. Montessori classrooms are typically larger and mixed age (e.g., grouping children ages 3 to 6 together) so that older children can serve as role models for younger ones.
November 24, 2025 at 6:21 PM
2/ PROGRAM. Montessori is a commonly used “alternative” educational model. Montessori classrooms are typically larger and mixed age (e.g., grouping children ages 3 to 6 together) so that older children can serve as role models for younger ones.
Here's the original study report: journals.sagepub.com/doi/epub/10....
journals.sagepub.com
November 24, 2025 at 6:06 PM
Here's the original study report: journals.sagepub.com/doi/epub/10....
Here's our No-Spin report: nospin.evidencebasedpolicy.org/articles/was....
Washington DC’s Opportunity Scholarship Program (Vouchers for Low-Income Students to Attend Private School) | No-Spin Evidence Review
nospin.evidencebasedpolicy.org
November 24, 2025 at 6:06 PM
Here's our No-Spin report: nospin.evidencebasedpolicy.org/articles/was....
6/ FINDINGS. The study found no discernible impact on the rate of college enrollment within 2y of students’ expected high school graduation. College enrollment was 43.0% for the treatment group vs 45.5% for the control group - a difference that wasn't statistically significant.
November 24, 2025 at 6:06 PM
6/ FINDINGS. The study found no discernible impact on the rate of college enrollment within 2y of students’ expected high school graduation. College enrollment was 43.0% for the treatment group vs 45.5% for the control group - a difference that wasn't statistically significant.
5/ Based on careful review, this was a high-quality RCT (e.g., baseline balance, negligible sample attrition, valid analyses).
November 24, 2025 at 6:06 PM
5/ Based on careful review, this was a high-quality RCT (e.g., baseline balance, negligible sample attrition, valid analyses).
4/ 87% of sample members were Black, 10% were Hispanic, and 51% were male. They averaged 12 years old and their average family income was approximately $18,000. 71% of lottery winners used their voucher to attend private school for at least 1 year.
November 24, 2025 at 6:06 PM
4/ 87% of sample members were Black, 10% were Hispanic, and 51% were male. They averaged 12 years old and their average family income was approximately $18,000. 71% of lottery winners used their voucher to attend private school for at least 1 year.
3/ STUDY DESIGN. The study sample comprised 1,780 students entering grades 2-12 who applied for a voucher in 2004 or 2005. A randomized lottery was used to determine who was offered a voucher (treatment) and who wasn't (control).
November 24, 2025 at 6:06 PM
3/ STUDY DESIGN. The study sample comprised 1,780 students entering grades 2-12 who applied for a voucher in 2004 or 2005. A randomized lottery was used to determine who was offered a voucher (treatment) and who wasn't (control).
2/ PROGRAM. The DC Opportunity Scholarship Program, created by Congress in 2004, provides scholarships (i.e., vouchers) to low-income DC families to attend private schools.
November 24, 2025 at 6:06 PM
2/ PROGRAM. The DC Opportunity Scholarship Program, created by Congress in 2004, provides scholarships (i.e., vouchers) to low-income DC families to attend private schools.
Here's the original study report: mdrc.org/sites/defaul....
mdrc.org
November 24, 2025 at 6:04 PM
Here's the original study report: mdrc.org/sites/defaul....
Here's our No-Spin report: nospin.evidencebasedpolicy.org/articles/suc....
SUCCESS, A Program Providing Coaching and Financial Support to Community College Students | No-Spin Evidence Review
nospin.evidencebasedpolicy.org
November 24, 2025 at 6:04 PM
Here's our No-Spin report: nospin.evidencebasedpolicy.org/articles/suc....
9/ The SUCCESS RCT is ongoing and will report on longer-term outcomes in the future.
Disclosure: Arnold Ventures, which funds No-Spin Evidence Review, helped fund the SUCCESS RCT.
Disclosure: Arnold Ventures, which funds No-Spin Evidence Review, helped fund the SUCCESS RCT.
November 24, 2025 at 6:04 PM
9/ The SUCCESS RCT is ongoing and will report on longer-term outcomes in the future.
Disclosure: Arnold Ventures, which funds No-Spin Evidence Review, helped fund the SUCCESS RCT.
Disclosure: Arnold Ventures, which funds No-Spin Evidence Review, helped fund the SUCCESS RCT.
8/ One possible reason: the program continued to enforce the full-time enrollment requirement, which may be critical to generating impacts.
November 24, 2025 at 6:04 PM
8/ One possible reason: the program continued to enforce the full-time enrollment requirement, which may be critical to generating impacts.
7/ We note, however, that another comprehensive student success program – ASAP, as delivered at Westchester Community College – was found to produce large impacts on college completion despite also being implemented & evaluated during the pandemic.
November 24, 2025 at 6:04 PM
7/ We note, however, that another comprehensive student success program – ASAP, as delivered at Westchester Community College – was found to produce large impacts on college completion despite also being implemented & evaluated during the pandemic.