Statistical analysis
REGRESSION, SECONDARY
The sample size was estimated based on a mean dietary diversity score of 3·26 (SD 1·40) using the women's dataset from the Alive & Thrive phase 1 endline survey for SNNPR, assuming an intra-cluster correlation (ICC) of 0·18, total cluster number of 54, 80% power to detect differences, and an α value of 0·05. We calculated that a sample size of 189 girls per group (seven per cluster) would be able to detect a minimum difference of 0·6 food groups. The sample size was rounded to 270 girls per group so that ten girls per school (two per grade) would be sampled, for a total sample size of 540 adolescent girls.Based on our baseline data (small subsample), we observed a mean dietary diversity score of 3·69 (SD 1·56) and an ICC of 0·015; using this information, we estimated that this sample size for the endline would detect a minimum difference of 0·5 food groups with 93% power.Descriptive analyses were conducted for sample characteristics and exposure to intervention components. Control variables used in the analyses included household wealth and household food security. Data on household asset ownership and housing characteristics were used to construct a wealth index using principal component analysis.The primary analysis was performed in the intention-to-treat population at endline. We estimated intervention effects using linear regression models for mean differences, with SEs clustered at the school level obtained using a sandwich estimator (unadjusted model). For binary outcomes, we reported intervention effects as odds ratios (ORs) and 95% CIs estimated from logistic regression models. In adjusted models, we controlled for adolescent age, region, household food security, and wealth. We examined a dose–response effect in the intervention group only by using multivariable regression analyses to test associations between exposure to the number of intervention components or the individual components and the primary and secondary outcomes, adjusted for adolescent age and geographical clustering. Two-sided This trial is registered at 