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INDEPENDENT RESEARCH CONFIRMS:
FROG STREET PRE-K DELIVERS
MEANINGFUL KINDERGARTEN READINESS
GAINS IN REAL CLASSROOMS.
INTRODUCTION
Johns Hopkins University conducted this study to examine kindergarten readiness outcomes in real classrooms.
Conducted in a large, diverse public school district with real classrooms, real educators, and real children, the findings provide clear, independent evidence you can review, share, and apply within your decision-making process.
As you evaluate options, this research offers a steady foundation grounded in real-world implementation.
WHY THIS
RESEARCH MATTERS
Decisions at this level require evidence that holds up under review. Many curriculum claims rely on internal studies or controlled settings. This research is different.
Johns Hopkins University conducted this study in real classrooms within a large, diverse public school district, comparing outcomes across existing programs under everyday conditions. That distinction matters when decisions are reviewed by boards, funders, and state agencies.
KEY FINDINGS
+0.37 NC-ELI Score Advantage
Children placed in Guilford County classrooms using the Frog Street Pre-K curriculum scored higher on overall kindergarten readiness than similar children in the district’s business-as-usual classrooms.
Approximately 10 Percentile Gain
Children performed measurably ahead of similar peers at kindergarten entry.
+0.26 Effect Size (Overall)
Johns Hopkins describes this as a large, educationally meaningful impact, statistically significant and relevant in practice.
+0.62 Effect Size for English Learners,
More than double the overall curriculum effect and statistically significant at p < .001. This result is based on a smaller subgroup and should be reviewed in that context. It represents a meaningful finding for curricula serving multilingual communities.
ABOUT THE STUDY
Conducted by Johns Hopkins University in Guilford County Schools, North Carolina, a large public school district serving approximately 67,000 children across 124 schools.The study reflected real-world implementation conditions, including varying levels of curriculum experience across participating classrooms.
Physical Development showed the strongest domain-level finding, with an effect size of +0.31. Johns Hopkins identifies this domain as central to school readiness.
The study meets ESSA Tier 3 Promising Evidence, as designated by the study's researchers, not by Frog Street, making it eligible for federal and state funding documentation. The study was conducted in a large, diverse public school district with real classrooms.
Grant, A.A., Cook, M.A., & Ross, S.M. (2026). Efficacy study of the Frog Street Pre-K Curriculum in Guilford County Schools. Center for Research and Reform in Education, Johns Hopkins University.
THE VALIDATION STACK
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Johns Hopkins
University
Identified statistically significant gains in kindergarten readiness through a structured, comparative study in real classrooms. This is peer-credible, independent research you can attribute to an institution when decisions are reviewed externally.
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ESSA Tier 3
Promising Evidence
Designated by the study's researchers, not by Frog Street. That distinction is what makes it credible in external review. It can be cited directly in Title 1, Head Start, and early childhood grant documentation.
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American Institutes
for Research (AIR)
Independent review confirming alignment to research-based practices and early learning standards. A second independent source strengthens the evidentiary case beyond a single study.
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Massachusetts
Curriculum Review
Five independent reviewers scored the curriculum against a state-aligned rubric. Developmentally Appropriate: 3.5 / Evidence-Based: 3.7 / Classroom Usability: 3.5 / Culturally Responsive: 3.7. These scores reflect how the curriculum performs against external quality standards, not internal claims.
WHAT THIS MEANS FOR YOUR ROLE
Superintendents
The study was conducted in real classrooms in a diverse public school district, providing you with specific, documentable evidence to present to your director or board when curricula decisions require external validation. The findings reflect outcomes for children in curricula like yours, under conditions like yours.
Directors of Early Childhood Education
The quasi-experimental design, transparent methodology, and clear findings give you evidence that holds up against curriculum expectations and standards review. The study was conducted in conditions that reflect real district implementation, not a controlled pilot.
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Curriculum Specialists
The full study, ESSA documentation, and independent validation sources are all accessible and can be reviewed as part of a formal evaluation process. Each component can be examined separately and compared against your own evaluation criteria.
Preschool Administrators
The study was conducted in a diverse public school district under real classroom conditions, offering relevant insight into how readiness develops across different learners. The findings connect directly to the children and families curriculums like yours serve.
FREQUENTLY ASKED QUESTIONS
Does this apply to my state?
The study was conducted in a large, diverse public school district reflecting many urban and suburban systems. It offers a relevant reference point for similar curricula.
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What does ESSA Tier 3 mean for funding?
It means the study meets federal criteria and can be cited in Title I, Head Start, and state early childhood grant documentation. The designation was determined by the study's researchers, not by Frog Street.
Was the population similar to mine?
The study included a diverse, multi-ethnic population with English learners, reflecting the composition of many large public school districts.
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