This Impact Map presents the estimated effects of interventions on student academic and wellbeing outcomes, moderated by contextual
and program characteristics. Each circle reflects the level of impact according to the statistical effect size, Hedge’s g,
from the meta-analyses of 75 studies (see Main Report).
To aid interpretation of the academic results in an educational context, effect sizes are interpreted in terms of
months additional learning, ahead of students in non-intervention control groups, based on the conversion metric
used by Evidence for Learning
and the Education Endowment Fund.