Six AI tutors individually matched human tutoring, with Gemma 4 31B equivalent at 918× lower cost per percentage point of learning gain¶

Claim · All claims
Evidence · 1 study · causal r2 · q2
Currency · newest study 2026 · not yet checked against its sources · not reviewed by a person

Subclaims¶

q2 i? Gemma 4 31B achieved learning gains statistically equivalent to expert human tutoring (p=.044) at 918× lower cost per percentage point of learning gain. → Curtis Northcutt 2026

Evidence¶

Curtis Northcutt 2026¶

Curtis Northcutt, Inaara Hasmani, Kevin Feng, Trevor Khangi, Andreas Plesner, Jonas Mueller. (2026). StudentBench: AI and human tutoring yield equivalent GRE learning gains. https://arxiv.org/abs/2609.28470 doi:10.48550/arxiv.2609.28470

q2 · i? · causal · r2

Individual equivalence tests against human tutoring across the 12 AI tutors; "Gemma 4 31B achieved GRE learning gains equivalent to expert human tutoring (p=.044)", with mean inference cost of $0.067 per session reported elsewhere. No standardized effect size printed.

"We test whether each AI tutor’s learning gains are equivalent to human tutoring, and find that Gemma 4 31B achieved GRE learning gains equivalent to expert human tutoring (p=.044) at918× lower cost per percentage point of learning gain."

Discussion¶

Related Claims¶

• Both AI and human tutoring produce larger GRE learning gains than a no-tutoring control — related
• Pooled AI tutoring produces statistically equivalent GRE learning gains to expert human tutoring — related
• Model family and instruction-tuning approach appear better predictors of tutoring quality than parameter count alone — related
• The best AI tutors exceeded human mean learning gains in Quantitative domains while human tutoring led pooled AI means in all Verbal domains — related
• In Quantitative AI sessions, faster AI replies were associated with more engagement, more correct practice, and larger learning gains; these associations were not significant in Verbal — related
• Intelligent tutoring systems improve achievement over non-individualised instruction — a broader claim this one bears on