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Published -
June 24, 2024

Effect Size Database

This report summarises the YEF’s Effect Size Database (ESDB), a free repository that reports effect sizes (ES) associated with each study included in the Youth Endowment Fund (YEF) Evidence and Gap map (EGM). It enables users to determine the direction and magnitude of impact reported in a particular study for a specific outcome, intervention, population group and context, reported as the standardised mean difference.

The database aims to help researchers efficiently design impact evaluations by presenting expected effect sizes associated with particular interventions and contexts. By providing a variety information associated with each ES, the database also aims to help researchers conduct future systematic reviews and meta-analyses.

The data were collected by a global team of 23 coders based in Bangladesh, Cameroon, Ghana, India, the Philippines, UAE, Uganda and the UK. This report details the process taken by these coders to create the ESDB, as well as present findings from analyses of the distributions of ES for relevant outcomes, participant groups, interventions and study designs.

The ESDB includes 14,834 ES on child-centred and offending and crime outcomes from 1,217 studies, of which more than 90 percent are from controlled studies (e.g., RCTs). Most of the ES (84%) were measured for child-centred outcomes (such as externalising behaviour, mental health and social cognition); 16 percent of the ES were measured for offending and crime outcomes (e.g., delinquency, contact with police, etc).

If you would like to access the full repository of effect sizes, for free, please email, and request the ESDB.