TeachBench: A Syllabus-Grounded Framework for Evaluating Teaching Ability in Large Language Models
Zheng Li, Siyao Song, Jingyuan Ma, Rui Li, Ying Zeng, Minghao Li, Zhifang Sui
TL;DR
This work treats teaching ability as a distinct dimension of LLM behavior and introduces a syllabus-grounded framework that evaluates teaching by measuring student performance gains after multi-turn instruction, all while preventing information leakage through structured knowledge points. It builds a knowledge-structure tree from Gaokao syllabi, uses LLMs to tag questions and generate practice problems, and employs web-enabled retrieval to source instructional material. Experiments on Gaokao data reveal that teaching effectiveness varies across subjects and models, with math, history, and politics easier to teach than physics and chemistry, and show that example problems do not universally improve teaching due to a shift toward error-correction behavior. Overall, the paper establishes that teaching ability is measurable and domain-dependent, offering a foundation for future research in AI-assisted pedagogy and teacher-agent design.
Abstract
Large language models (LLMs) show promise as teaching assistants, yet their teaching capability remains insufficiently evaluated. Existing benchmarks mainly focus on problem-solving or problem-level guidance, leaving knowledge-centered teaching underexplored. We propose a syllabus-grounded evaluation framework that measures LLM teaching capability via student performance improvement after multi-turn instruction. By restricting teacher agents to structured knowledge points and example problems, the framework avoids information leakage and enables reuse of existing benchmarks. We instantiate the framework on Gaokao data across multiple subjects. Experiments reveal substantial variation in teaching effectiveness across models and domains: some models perform well in mathematics, while teaching remains challenging in physics and chemistry. We also find that incorporating example problems does not necessarily improve teaching, as models often shift toward example-specific error correction. Overall, our results highlight teaching ability as a distinct and measurable dimension of LLM behavior.
