TechRxiv paper proposes dual-run comprehension delta to measure teaching efficacy

[TechRxiv] A TechRxiv preprint by Rohith Namboothiri proposes a measurement construct called the dual-run comprehension delta, which reframes teaching efficacy as the measurable change in a standardized evaluator's comprehension before and after receiving a teacher's explanation. According to the paper, existing approaches rely on classroom observation protocols requiring trained human raters or on student evaluations that correlate poorly with actual learning outcomes, and both suffer from subjectivity, scalability constraints and documented biases. The author argues that large language models can serve as controlled learner proxies and develops a formal framework in which a domain-specific assessment is administered to an LLM twice, once without access to the teacher's explanation and once with it, with the score difference constituting the delta. The paper grounds the construct in validity theory from the Standards for Educational and Psychological Testing, analyzes it through pedagogical content knowledge and explanation quality research, and presents a reference architecture instantiating the methodology. The author says the dual-run delta offers a reproducible and scalable complement to existing teaching quality measures, particularly for asynchronous instruction, teacher certification and professional development, and outlines a validity argument around Kane's interpretation/use framework, discusses construct boundaries and identifies empirical studies needed to evaluate its claims. The paper is a preprint and has not been peer reviewed.