Can Academic Redshirting Shrink the Education Gender Gap? Causal Evidence on Student Achievement and Mental Health

I study voluntary delays in the school entry of age-eligible children (academic redshirting), using Hungarian administrative test score and medical prescription data, and mental health surveys. I identify a new Local Average Treatment Effect of starting school a year older due to redshirting, by exploiting a school-readiness evaluation required only for potentially redshirted children born before January 1. Instrumenting with post-January 1 births, I estimate effects for non-school-ready children who could overcome developmental deficits with redshirting but are deterred by the evaluation. I find improved test scores, high school track choices, educational aspirations, and graduation rates - but only for boys, who are also less anxious, more confident, and less bullied. Redshirting thus shrinks gender gaps, such as closing the high school completion gap by 60 percent.