As the catch-all term “AI tutoring” captures the public imagination, it’s time to define and measure what actually meets the bar for a “tutor.”
A new SCALE brief from Stanford offers a useful route through this definitional problem. Instead of sorting tutoring models by how sophisticated their AI appears, AI Tutoring Is Not a Monolith places them on a spectrum of relational intensity: the depth and consistency of the human connection surrounding the student.
At the high-intensity end, a human tutor leads the instruction and holds the relationship, while AI may assist with lesson preparation, data analysis, or suggestions. In the middle, the student works directly with an AI tutor while a person oversees the process and intervenes. At the lowest-intensity, the student works with an AI-only tutor without direct human oversight.
This framework does not assume that more human contact always makes a tool better (ex: A well-designed hybrid can use AI to remove administrative work and give a human tutor more time for the relationship). It also doesn’t assume that every student needs the same degree of support.
It does show where the evidence is strongest: High-impact tutoring is still defined by live, human-led instruction. The evidence becomes thinner as direct human involvement decreases. At present, SCALE concludes that AI-led tutors may offer valuable supplemental practice, but do not yet inherit the definition or evidence base of high-impact tutoring simply because they provide one-to-one responses.
That evidence base is unusually deep. In a 2026 synthesis, Loeb and Carly Robinson report that meta-analyses estimate average effects of 0.29 to 0.37 standard deviations on student achievement, making tutoring one of the most effective interventions in education research. The strongest programs also tend to share a recognizable architecture:
- Students and tutors meet frequently, 1:1 or in small groups
- Tutoring connects to classroom curriculum
- Tutors use evidence of student understanding to adjust instruction
- The same tutor works with the student over time
- Tutors receive training, materials, and ongoing support
