Do Intelligent Tutoring Systems Benefit K-12 Students? A Meta-Analysis and Evaluation of Heterogeneity of Treatment Effects in the U.S.

Meta-analysis of 18 US K-12 experiments meeting WWC standards: tutoring systems vs regular teaching g = 0.27 overall, 0.20 on standardised tests (0.166 to 0.234), 0.16 at the end of the school year, 0.11 (ns) for use longer than six months; half the effects from one reading tutor (ITSS). Kill-condition test, C10 survived 2026-11-15. Submitted version read.