Growth-Mindset Intervention Delivered by Teachers Boosts Achievement in Early Adolescence

1,996 students and 50 teachers, US grades 6-7, teacher-level randomisation

United States; middle-school students in grades 6 and 7.

Two flags, both serious. First, the commercial conflict - two authors are employees of Mindset Works Inc., the for-profit vendor of Brainology, the exact product under evaluation, and one of them is the first author of the founding 2007 paper. This is precisely the category Macnamara and Burgoyne quantified as 2.5 times more likely to report a positive result. Second, Psychological Science subsequently REMOVED the paper's Preregistered badge in a 2023 corrigendum after data collection was truncated. Teacher-level randomisation by an independent contractor, no-treatment control, monthly 30-60 minute lessons, outcome is end-of-year report-card grades from district records, which are teacher-assigned rather than standardised. Baseline imbalance noted on grade composition.

Struggling students in the class where Brainology was taught improved by beta = 0.27 (95% CI 0.10 to 0.44), equal to 2.81 grade percentage points. Higher-achieving students showed beta = 0.07 (-0.10 to 0.25), a null. Non-target classes 0.14 (-0.02 to 0.30), not significant. The moderator result is the interesting one - effects were LARGEST where teachers held pre-intervention FIXED mindsets (beta = 0.40, 0.20 to 0.60, 4.16 grade points), the exact opposite of what Yeager et al. 2022 reported from the National Study of Learning Mindsets.

Low - teacher-level randomisation within school and grade.

Unreplicated, and it contradicts the developer side's other teacher-mindset moderation result published the same year. Two developer-authored papers, opposite moderators, no reconciliation.