Public schools in the United States have struggled to boost student achievement in math and reading following the Covid-19 pandemic. Funding from the Elementary and Secondary School Emergency Relief Fund (ESSER) contributed to modest post-pandemic achievement gains in math—but we still don’t know how exactly these funds made a difference.
In a new brief titled “School’s in for Summer: A Scalable and Effective Post-Pandemic Academic Intervention,” researchers at the Center for Analysis of Longitudinal Data in Education Research (CALDER) assess findings from two studies of ESSER-funded summer school programs delivered in 2022 and 2023 across ten large school districts to evaluate the effectiveness of summer school relative to other post-pandemic interventions. These district-run, school-based summer school programs delivered instruction across several weeks in core subjects such as math and reading, rather than individualized tutoring. Programs also incorporated social-emotional learning and enrichment activities, including physical education, art, music, dance, and gardening.
To gauge the impact of this intervention, they use value-added models that control for prior achievement and other observable characteristics of students to estimate the effects of participating in summer school on students’ fall NWEA MAP Growth math and reading test scores.
Overall, they find that summer school increased students’ math scores by 0.027 SD in 2022 and by 0.024 SD in 2023. Interestingly, while students showed improvement in math, reading scores showed no measurable improvement following summer school. For math, these impacts translate into roughly 10 to 15 extra days of learning over the course of a 180-day school year.
Although these increases in math are statistically significant, they are notably smaller than the 0.10 SD gains associated with attending summer school in pre-pandemic studies. The post-pandemic programs considered in the studies also produced smaller math gains per instructional hour than pre-pandemic programs. There is no clear explanation for why summer school only produced gains in math, but these findings are consistent with pre-pandemic evidence suggesting that summer school and other school-based instruction can produce stronger gains in math than reading.
Researchers from CALDER also compared outcomes from post-pandemic summer school programs with tutoring interventions during the school year and found that summer school was more effective for district-wide academic recovery. A key reason for this difference appears to be implementation at scale. Large-scale tutoring interventions in similar districts produced no measurable gains in student achievement, largely because districts struggled to deliver sufficient tutoring hours. In contrast, effective tutoring programs served fewer students and delivered at least 30 hours of instruction, suggesting that tutoring can benefit small groups of students, but is challenging to implement effectively at scale.
Compared to tutoring interventions, the summer school programs were better able to deliver sustained instructional dosage at scale. Findings from CALDER indicate that the most successful pre-pandemic summer school programs lasted four to six weeks and provided 90 minutes of math and 120 minutes of reading per day, helping explain their stronger average district-wide impacts compared to tutoring, even though participation was limited to a subset of students. However, several programs examined in 2022 and 2023 fell short of these targets, highlighting that summer school’s effectiveness depends on maintaining sufficient instructional time.
Although school districts would ideally implement both small-scale tutoring and summer school to support post-pandemic academic recovery, cost-effectiveness is a key consideration. Small-scale tutoring is effective in producing academic gains but requires low student-teacher ratios, making it expensive to staff. Summer school has proven to be just as effective in producing academic gains in math while serving more students with higher student-teacher ratios, making it a less costly solution for large-scale academic recovery. If school districts want to boost achievement, especially in math, adopting a well-designed summer school programs can be a smart strategy.
SOURCE: Emily Morton, Dan Goldhaber, Thomas J. Kane, and Andrew McEachin, “School's in for Summer: A Scalable and Effective Post-Pandemic Academic Intervention,” CALDER Center for Analysis of Longitudinal Data in Education Research (December 2025).
