24 March 2026
Is Small-Group Tutoring as Effective as 1-on-1? What the Research Says
We look at the academic evidence comparing small-group and private 1-on-1 tutoring to see which model actually helps students learn more effectively.
When parents look for a maths tutor, the default assumption is often that one-on-one is the gold standard. The logic seems simple: 100% of the teacher's attention must equal 100% better results.
But when you look at the actual educational research, the picture is more nuanced. For many students, small-group tutoring (2-4 students) is not just a "budget" alternative—it is a highly effective instructional model that often matches or even exceeds the impact of one-on-one sessions.
Here is what the latest academic meta-analyses and trials tell us.
1. The "Effect Size" Reality Check
In educational research, "Effect Size" (SD) measures how much an intervention improves student outcomes compared to a standard classroom.
A landmark 2024 meta-analysis by Nickow, Oreopoulos, and Quan, published in the American Educational Research Journal, reviewed dozens of randomized experiments. They found that tutoring (both 1-on-1 and small-group) yields an overall pooled effect size of 0.288 SD, which is considered a "consistently substantial positive impact."
Interestingly, when comparing different studies:
- Some research (e.g., Pellegrini et al., 2018) actually found a higher effect size for small-group tutoring (0.32 SD) than for one-on-one tutoring (0.26 SD) in elementary maths.
- Other reviews (e.g., Inns et al., 2019) found 1-on-1 slightly higher (0.31 SD vs 0.20 SD), but both remained far superior to standard classroom-only instruction.
The Takeaway: The difference in learning gains between 1-on-1 and a well-run small group of 3 is often statistically negligible. Both are "high-impact" compared to almost any other educational intervention.
Source: Nickow et al. (2024) - The Promise of Tutoring for PreK–12 Learning (Full text also available via NBER)
2. Why Small Groups Work: The Peer Effect
One reason small groups perform so well is a phenomenon called peer learning. In a 1-on-1 setting, the student can become overly dependent on the tutor for every step. In a small group:
- Reduced Pressure: Students often feel less "under the microscope," which can lower maths anxiety.
- Peer Explanations: Research shows that when a student explains a concept to a peer, both students' understanding deepens.
- Normalization: Seeing a peer struggle and then succeed with a problem helps students build mathematical resilience.
A study published in PMC found that peer-assisted learning significantly reduces mathematics anxiety in middle school students, creating a more sustainable learning environment than the high-pressure 1-on-1 dynamic.
Source: Peer tutoring and maths anxiety (2020)
3. The "High-Dosage" Factor
The UChicago Education Lab and Saga Education have conducted extensive research into "High-Dosage Tutoring." Their model typically uses a 2:1 or 3:1 student-to-tutor ratio.
Their findings across thousands of students in high-poverty schools showed that this small-group model was able to double or even triple the amount of maths students learned in a single year. The key wasn't the 1-on-1 ratio; it was the consistency, the relationship, and the curriculum alignment.
Source: UChicago Education Lab - Saga Education Research Partnership
4. When 1-on-1 is Necessary
Research by Kraft and Lovison (2024) suggests that for online tutoring specifically, 1-on-1 can sometimes be more effective if the platform or tutor isn't equipped to manage a group.
This is why at No Drama Koala, we use a specific "micro-group" structure. We don't just put 3 kids in a Zoom call and hope for the best. We use Mathspace for real-time tracking, allowing the teacher to see every student's digital "scratchpad" simultaneously. This gives us the visibility of 1-on-1 with the social and pedagogical benefits of a small group.
Source: Kraft & Lovison (2024) - The Effect of Student-Tutor Ratios
Summary: Focus on Quality, Not Just Ratio
The "2-Sigma Problem" posed by Benjamin Bloom in 1984 suggested that 1-on-1 tutoring is the ideal. However, 40 years of subsequent research has shown that high-quality small-group tutoring (ratios of 1:2 to 1:4) captures the vast majority of those gains while being more sustainable for families and often more engaging for students.
If you are looking for a "safety net" that builds independence rather than dependence, the research suggests a small, expert-led group is an excellent choice.