The Importance of Relative Standards in ADHD Diagnoses: Evidence Based on Exact Birth Dates
37 Pages Posted: 19 Dec 2009
Date Written: December 18, 2009
This paper presents evidence that diagnoses of Attention-Deficit / Hyperactivity Disorder (ADHD) are driven largely by subjective comparisons of children to their peers. Children born just prior to their state’s cutoff date for kindergarten eligibility – who typically become the youngest and most developmentally immature children within a grade – are 50 percent more likely to be diagnosed with ADHD than those born immediately afterward. A child’s birth date relative to the eligibility cutoff also strongly affects teachers’ assessments of whether the child exhibits ADHD symptoms but is only weakly associated with similarly measured parental assessments, implying that many diagnoses merely reflect teachers’ perceptions of poor behavior among the youngest children in a classroom. These perceptions have long-lasting consequences: the youngest children in fifth and eighth grades are nearly twice as likely as their older classmates to regularly use stimulants prescribed to treat ADHD.
Keywords: ADHD, symptoms, diagnoses, regression discontinuity
JEL Classification: I10, I21, J13, J24
Suggested Citation: Suggested Citation