As K-12 school districts continue to invest in academic recovery, a central question is emerging: what actually drives achievement?
That question shaped a recent LinkedIn live conversation following the recent release of CALDER research examining summer school programs across ten large districts serving nearly 450,000 students. It found that summer school consistently boosted math achievement, with gains equivalent to roughly two to three weeks of learning during the school year. Reading outcomes showed no measurable improvement.
To explore what these findings mean for district leaders, Nancy Livingston, CEO of the National Summer School Initiative, spoke with Liz Cohen, VP of Policy at 50CAN and author of The Future of Tutoring, and Dr. Sarah Scott Frank, CEO of Open Literacy. Together, they explored summer school, high-dosage tutoring, and the design conditions that determine whether either strategy delivers results.
The conversation did not center on choosing one intervention over another. Instead, it focused on scale, instructional quality, and how districts can design summer learning programs that strengthen core instruction. What surfaced was simple: the effectiveness of summer school or tutoring depends less on the chosen intervention and more on how well it is designed and implemented to support student learning.
What the CALDER Study Found About Summer School and Tutoring
The 2026 CALDER research examined summer school programs across ten large districts serving nearly 450,000 students. The findings were clear:
- Summer school consistently improved math achievement. Gains were modest, about two to three weeks of learning, but statistically significant across districts.
- Reading outcomes showed no measurable improvement.
- Most programs operated below recommended duration and instructional intensity.
- Even so, summer school reached an average of 13 percent of eligible students and produced reliable math gains.
- Large-scale, post-pandemic high-dosage tutoring programs showed mixed results, particularly when dosage fell short.
The researchers concluded that summer school is a viable and scalable intervention for district-wide math recovery. Liz Cohen cautioned against oversimplifying the comparison, noting that tutoring showed effects, but that results declined as programs scaled and implementation varied. For district leaders, the question is not simply which intervention wins. It is how well each is implemented.
Summer School vs. High-Dosage Tutoring: Why the Zero-Sum Debate Misses the Point
It would be easy to read the CALDER findings as a comparison between summer school and high-dosage tutoring. The panel did not take that path.
Liz Cohen put it plainly: “I don’t actually care if kids get tutored or go to summer school. I care very much if kids learn.” Her point was not to minimize structure, but reframe it. Tutoring has a strong research base, particularly in smaller, well-controlled settings. The challenge has been scaling those programs with consistent dosage, alignment, and attendance.
At the same time, the summer school results are not incidental. Even operating below recommended duration and intensity, programs produced consistent math gains across districts. For Nancy Livingston, that reliability matters. When a strategy reaches thousands of students and produces measurable gains, even modest ones, it becomes a meaningful lever at the system level.
The question is not which intervention wins. As Dr. Sarah Scott Frank put it, “What conditions need to be in place for kids to continue to make learning gains in the summer?” The real issue is whether districts are designing coherent systems that allow students to learn.
Why Summer School Matters for District-Wide Math Recovery
At its core, this is a conversation about time, how districts structure it across the school day, the school year, and the summer months. Liz broadened the lens beyond individual programs. “We’re really trying to have a conversation about how we think about time,” she said, noting that time can take many forms. Tutoring represents targeted, intensive time for specific students. Summer school represents structured instructional time that districts already know how to organize at scale.
Summer programs in the study served an average of 13 percent of eligible students and often reached well over 1,500 students in a single district. When gains occur across that many students, they influence district-wide recovery in ways smaller programs cannot.
This does not diminish the value of high-dosage tutoring; tutoring may be best suited as a focused intervention for students who need the most intensive support. Summer school, by contrast, offers districts a platform to reinforce grade-level learning across a broader population. As Liz noted, families are already seeking both supports on their own. The equity challenge for districts is ensuring access does not depend on a family’s ability to procure it privately.
Reading Outcomes in Summer School: A Design Signal for District Leaders
The absence of measurable reading gains in the CALDER study deserves careful attention. Rather than viewing it as a verdict on summer learning, the panel saw it as a signal about instructional design.
Dr. Sarah Scott Frank began with a practical question: “Who is staffing summer?” Programs must be designed for the educators delivering them. A curriculum that works for a seasoned classroom teacher using school-year materials may fall apart if implemented by less experienced staff without strong routines.
She raised a second, more pointed question: “How much time were students actually reading text?”
In many classrooms, even during the school year, students spend surprisingly little time reading connected text. If summer becomes a mix of loosely connected activities or isolated skills practice, comprehension growth is unlikely. “Do students have opportunities to read connected text?” she asked, adding that, without sustained reading and discussion, gains should not be expected.
Nancy Livingston offered a concrete example from NSSI’s K–2 implementation. Early site visits revealed that when time ran short, “sometimes the part that would get cut…was the decodable.” Her takeaway was clear: “Just make sure they read.” Protecting daily reading time is not optional; it is foundational.
The broader lesson is not that summer school cannot improve reading. It is that reading outcomes depend on disciplined instructional design. Who teaches, what gets protected in the schedule, and how closely summer aligns to the school-year curriculum all matter. When those pieces are coherent, the conditions for literacy growth strengthen. As Nancy Livingston said during the conversation, “The whole thing has to work together as a functioning teaching and learning strategy.”
Building Coherent Summer School and Tutoring Systems
The CALDER research positions summer school as a viable and scalable intervention for supporting math recovery at the district level.
Summer school and high-dosage tutoring serve different functions within a district’s strategy. Tutoring offers targeted intensity. Summer provides structured reach. Both require careful design, sufficient dosage, strong leadership, and ongoing data use.
The goal is not to choose one over the other. As Liz put it, “I don’t actually care if kids get tutored or go to summer school. I care very much if kids learn.” The task for district leaders is to design systems where time, instruction, and support align.
For NSSI, that means treating summer school not as an isolated program, but as an extension of the instructional core. Summer provides structured reach. Tutoring provides targeted intensity. When both are coherent, instructionally strong, and integrated with year-round priorities, modest gains can accumulate across thousands of students. Over time, that coherence becomes one of a district’s most reliable levers for advancing student learning.
This content is derived from a LinkedIn Live webinar hosted by NSSI featuring Nancy Livingston, Liz Cohen, and Dr. Sarah Scott Frank. Follow NSSI on LinkedIn for more conversations on summer learning, instructional design, and district strategy.
