A major expansion of preschool and prekindergarten in California during the 2010s produced measurable improvements in pupils' later achievement and helped narrow the attainment gap between children from wealthier and poorer families, according to new research from the University of California, Berkeley.
Lasting effects into third and fourth grade
The report, authored by Professor Rucker Johnson and researcher Austin Land, finds that children who attended the state’s expanded preschool programmes showed significantly higher performance in later elementary school. By third and fourth grade those pupils were performing ahead of peers who had not attended the programmes, with improvements described by the authors as persistently evident years after attendance.
The study quantifies the benefits as roughly one year of additional progress in reading and about eight months of additional progress in mathematics for pupils who had been through the new preschool provision compared with those who had not.
“This combination of public preschool at 3 and 4 years of age dramatically helped young children build stronger reading and math skills,”
Professor Johnson and Mr Land further report that when expanded preschool access was combined with increased funding for elementary schools – targeting improvements in teaching and learning programmes – the gains became larger and more persistent. They note that pupils from low‑income families received additional benefit when their elementary schools also experienced increased investment.
Policy implications and context
The research, released in a report titled Who Benefits From Universal Prekindergarten?, was published ahead of a Sacramento policy briefing organised by the Learning Policy Institute and Early Edge California. It is presented as the first study of its kind to assess the cumulative impact of state-level preschool expansion alongside subsequent elementary school funding increases.
Although the study focuses on California, its findings will feed into wider debates about the merits of universal early years provision and the sequencing of investment across the school years. The authors emphasise that early interventions can set children on stronger learning trajectories that persist into later primary school, and that complementary investment in the early grades amplifies those effects.
- Key measured gains: ~1 year higher reading attainment; ~8 months higher maths attainment by third/fourth grade.
- Targeted benefit: Additional improvements for children from low‑income backgrounds when elementary funding rose.
- Combined approach: Preschool plus strengthened elementary resourcing produced larger, longer‑lasting gains.
Evidence for classroom realities
The authors, experienced education researchers, place their conclusions in the context of sustained policy effort across a decade. They argue that the combination of earlier access to high‑quality preschool for three and four year‑olds and later support in primary schools prepared pupils to become more effective learners as they progressed through the system.
For policy makers, headteachers and classroom teachers, the findings point to two practical messages: that investment in the early years can deliver durable improvements in literacy and numeracy, and that those returns are enhanced when follow‑on funding supports quality in the first years of school. The report therefore provides empirical support for strategies that view preschool expansion and primary school improvement as linked components of a single reform agenda.
| Outcome | Estimated benefit |
|---|---|
| Reading (by Grade 3–4) | ~1 year |
| Mathematics (by Grade 3–4) | ~8 months |
The study will be of interest beyond California as governments and education authorities consider how best to allocate limited resources to raise attainment and reduce inequality. While the research does not make prescriptions for other jurisdictions, it furnishes evidence that early, sustained public investment in children’s learning can have consequences that endure into the primary‑school years.
