Abstract
This study investigates the causal effect of relative age at school entry on the likelihood of being identified with special educational needs (SEN) or diagnosed with attention deficit/hyperactivity disorder (ADHD) in Germany. Drawing on representative data from the National Assessment Studies (IQB) for Grades 4 and 9, we use a two-stage least squares (2SLS) instrumental variable approach, leveraging exogenous variation in school starting age created by state-specific enrollment cutoff dates. Results indicate that relatively younger students within a grade cohort are significantly more likely to be classified with SEN, particularly in the domains of learning and developmental disorders, with effects being more pronounced in Grade 9 than in Grade 4. Similarly, we find robust evidence of a relative age effect on ADHD diagnoses in Grade 4, although this effect diminishes by Grade 9. The findings suggest that age-related maturity differences systematically influence assessment and diagnostic decisions. Our results highlight the need for developmentally sensitive and bias-mitigating assessment practices that do not rely solely on teacher judgments, in order to avoid misclassification and ensure educational equity.
Get full access to this article
View all access options for this article.
References
Supplementary Material
Please find the following supplemental material available below.
For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.
For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.
