Outcomes
Evidence districts can rely on.
When you’re defending a tutoring investment to your board, or deciding whether to renew, you need more than testimonials and promises. You need data that holds up to scrutiny: independent research, specific metrics, and honest reporting on what works, where, and for whom.
What the evidence shows.
K12 Tutoring’s evidence portfolio spans ESSA Levels II through IV, covering grades 1–12 across literacy, math, and ELA. The consistent finding: students who spend more time in tutoring tend to show stronger academic outcomes, particularly students who start below benchmark.
Here’s the headline data from independent evaluations:
Early Literacy
(Grades 1–3)
33%
more growth on Renaissance Star Reading assessments
for tutored students vs. the matched comparison group
Quasi-experimental design with propensity score matching
Elementary Math
(Grades 2–6)
44%
more growth on Renaissance Star Math assessments
for tutored students vs. the matched comparison group
Students receiving higher-dosage tutoring (12+ hours) showed the greatest gains.
Quasi-experimental design with propensity score matching
Middle Grades Math
(Grades 4–8)
Positive Association
between tutoring time and Virginia SOL math scores
across multiple grade levels. Students who spent more time in tutoring tended to earn higher scores.
Correlational study, single district
High School Performance
(Grades 9–12)
+5.7%
math grade increase
per 15 hours of tutoring
+6.0%
ELA grade increase
per 15 hours of tutoring
Correlational study across multiple virtual schools
Important context
These findings reflect outcomes under specific implementation conditions. Results vary based on dosage, student starting point, and how tutoring is integrated into the school day. We’re transparent about where evidence is strongest and where research is ongoing.
How districts made it work.
Numbers matter. So does context. These case studies show how tutoring played out in real districts: the challenges they faced, the approach they took, and the outcomes they measured.
Pulaski County Public Schools, Virginia
District Profile:
Rural Virginia district serving approximately 4,200 students across multiple schools. Post-pandemic learning loss had created significant gaps, particularly in math and ELA for grades 3–8.
The Challenge:
Pulaski County faced the same constraints many districts face: staffing shortages limited their capacity to deliver small-group intervention internally. They needed a partner who could scale support without adding burden to existing teachers.
The Approach:
K12 Tutoring was integrated into the school day. Over 850 students in grades 3–8 participated, completing more than 4,000 sessions between November 2023 and April 2024. Students were grouped by skill level and worked with the same certified tutor throughout the program.
The Outcomes
Grade/Subject
Avg. Percentile Gain
3rd Grade Math
+40 points
3rd Grade ELA
+30 points
6th Grade ELA
+39 points
Grades 3–8 Math (avg)
+13 points
Grades 3–8 ELA (avg)
+18 points
What District Leaders Said
“We’ve seen anywhere from a 13% to 44% increase in students who had tutoring, as opposed to those who did not.”
– Dr. Robert Graham, Superintendent
“Having certified teachers makes a huge difference. You have to have someone who knows what they’re doing.”
– Rebecah Smith, Middle School Principal
“The best thing about the partnership is an added resource… The gift of time—the teachers have time to use on other things in their classrooms while students are still learning.”
– Anthony Viers, Elementary Principal
Additional Case Studies
More district case studies coming soon. We’re documenting outcomes across different district sizes, grade configurations, and implementation models.
The data, in detail.
This section provides the specific metrics, comparison approaches, and context behind our outcomes data. We include effect sizes, study designs, and honest notes on where evidence is strongest.
Understanding the Measures
Effect sizes help compare results across different studies and assessments.
Hedges’ g
Standardized effect size comparing tutored vs. non-tutored groups. g = 0.20 is considered a small-to-moderate effect.
Omega squared (Ω²)
Proportion of variance in outcomes explained by tutoring time. Higher values indicate stronger associations.
Percentile gain
Movement within the distribution of student scores (e.g., from 30th to 40th percentile).
Grade increase
Percentage point improvement in course grades (e.g., from 75% to 80.7%).
Comparison Groups and Methodology
Our strongest evidence comes from quasi-experimental designs that compare tutored students to similar students who did not receive tutoring:
We do not claim causal effects where study designs don’t support them. Correlation studies show association, not causation.
Results by Grade Band
Early Elementary (Grades 1–3)
Assessment: Renaissance Star Reading
Effect Size: g = 0.20
Students receiving K12 Tutoring demonstrated stronger growth on reading assessments than matched peers who did not receive tutoring. The difference was especially meaningful for students who entered well below benchmark.
Upper Elementary (Grades 2–6)
Assessment: Renaissance Star Math
Effect Size: g = 0.21
Students who received K12 Tutoring outperformed matched peers on end-of-year math assessments. Higher-dosage tutoring (more than 12 hours) was associated with the greatest gains.
Middle Grades (Grades 4–8)
Assessment: Virginia SOL
Effect Size: Ω² = 0.06 to 0.12 (Math)
Students who spent more time in tutoring tended to earn higher math scores, even after accounting for where they started academically.
Note on reading: Analyses did not show a statistically significant association between tutoring time and SOL reading performance in this study. This suggests opportunities to refine how reading support is targeted. We share this transparently because nuanced evidence helps districts make informed decisions.
High School (Grades 9–12)
Assessment: Course grades (Math & ELA)
Effect Size: +5.7% to 6.0% per 15 hours
Students who accumulated more tutoring hours tended to earn higher course grades than peers with less tutoring exposure. Course grades are a key indicator of credit accumulation and graduation progress.
Aligned to ESSA evidence standards.
ESSA evidence levels matter for funding eligibility and for confidence in results. Here’s how K12 Tutoring’s evidence portfolio aligns to federal standards.
ESSA Evidence Levels Explained
Level
Standard
What It Means
Level
Level I
Standard
Strong Evidence
What It Means
Randomized controlled trial showing positive effects
Level
Level II
Standard
Moderate Evidence
What It Means
Quasi-experimental study showing positive effects
Level
Level III
Standard
Promising Evidence
What It Means
Correlational study with statistical controls
Level
Level IV
Standard
Demonstrates a Rationale
What It Means
Logic model based on research; an ongoing study is planned
Why This Matters for Districts
ESSA evidence levels affect funding eligibility. Many federal and state programs require evidence-based interventions. Our Level II and III evidence supports:
Research Foundation
K12 Tutoring’s approach is grounded in high-impact tutoring research from leading institutions:
Stanford’s National Student Support Accelerator
Research on tutoring dosage, tutor quality, and integration with the school day.
Brown University
Studies on relationship-based tutoring and student engagement.
Johns Hopkins University
Evidence on small-group instruction and achievement effects.
Translating research to practice
Our program design reflects this research: small groups, consistent tutors, frequent sessions, and alignment to classroom instruction. We don’t just cite research; we build operational models around it.
Realistic expectations for your district.
Evidence from research studies provides a foundation. Here’s what success typically looks like in practice: timelines, benchmarks, and the signals that indicate a program is working.
Typical Timelines for Impact
Weeks 1-4
Implementation and calibration. Attendance patterns are established. Tutors learn students’ needs.
Weeks 5–8
Early engagement signals. Participation stabilizes. Tutors and teachers coordinate on focus areas.
Months 9-12
Measurable benchmark movement for students with consistent attendance. First outcome data available.
Semester 1
Documented gains on progress monitoring assessments. A clearer picture of which students are responding.
Full Year
Benchmark and state assessment data. Year-over-year comparison possible.
Districts should not expect dramatic results in the first month. High-impact tutoring works through sustained engagement over time.
Benchmarks by Grade Band
Based on district outcomes and research findings, here are reasonable expectations for students with consistent participation:
Grade Band
Subject
Typical Outcome Range
Grade Band
K–2
Subject
Literacy
Typical Outcome Range
15–35 percentile point gain on benchmark assessments
Grade Band
3-5
Subject
Math
Typical Outcome Range
10–25 percentile point gain on benchmark assessments
Grade Band
3-5
Subject
ELA
Typical Outcome Range
10–20 percentile point gain on benchmark assessments
Grade Band
6-8
Subject
Math
Typical Outcome Range
Positive association with state assessment scores (varies by dosage)
Grade Band
9-12
Subject
Course grades
Typical Outcome Range
5–10 percentage point improvement with 15+ hours of tutoring
Important: These ranges reflect outcomes for students with consistent attendance (3+ sessions per week) who started below the benchmark. Students closer to grade level may show smaller gains. Students with very low attendance will not see these results.
Tier 2 vs. Tier 3 Success Indicators
Tier 2 (Targeted Intervention)
Tier 3 (Intensive Intervention)
Qualitative Signals
Numbers aren’t everything. District partners also report:
See what this could look like for your district.
You’ve seen the evidence. The next step is understanding what outcomes are realistic for your specific context: your students, your grade bands, your timeline.
How we track and share progress data