Carol Dweck's original studies and many smaller trials reported achievement gains from growth mindset interventions, but a 2019 randomized controlled trial run by the Education Endowment Foundation across many schools found no significant increase in numeracy or literacy from the training. Advocates and critics differ on whether the effect is real but small and context dependent, or whether the early results simply do not replicate at scale.
What would resolve this Additional large, independently run randomized controlled trials across varied school settings, with pre registered outcome measures, would show whether the training's effect on achievement holds up outside the original research team's own studies.
OpenEducational psychologyWikipedia: Mindset