Fact · Accessibility and health
1.23weighted mean effect size
Across the studies, children with ADHD scored well below controls on expressive language, with a weighted mean effect size of 1.23.
Checked against its source on October 16, 2026
In the source's own words
“Follow-up meta-analyses found evidence for large deficits in the ADHD groups overall (10/11 studies met p < .05; weighted mean ES [WMES]: 1.04); expressive (10/10 met p < .05; WMES: 1.23)”
Research Review: Language problems in children with Attention-Deficit Hyperactivity Disorder - a systematic meta-analytic review, Hanna Korrel et al., Journal of Child Psychology and Psychiatry, 2017, Abstract, Results.
Open the original (DOI 10.1111/jcpp.12688)- What it measures
- Expressive language means producing words and sentences. The same review gives 0.97 for receptive language and 0.98 for pragmatic language, the social use of language.
- What it does not show
- The effect size reflects group averages on standard tests, and the authors note that the deficits may reflect psychiatric or social factors as well as language-specific problems.