Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
After‐school tutoring has risen globally despite limited evidence of effectiveness. We implement a randomized after‐school tutoring program in rural China where many children are left‐behind by parents in care of grandparents. Compared to tutees cared for by parents, those in care of grandparents reported much smaller home‐tutoring reductions but larger test‐score gains. We interpret our data analysis with a model with tutoring efficacy and substitution between private and public inputs both differing by family background: Increased public tutoring generates larger test‐score gains for children who experience greater tutoring efficacy and lesser substitution with household inputs, consistent with our estimates.