Measuring Inappropriate Medical Diagnosis: The Case of ADHD

Within a kindergarten classroom, depending on state eligibility laws, children’s ages can vary by one full year. A new study, published online in August 2010 by the Journal of Health Economics, explores how the difference in age when children start kindergarten can influence ADHD diagnosis and treatment.

The researchers suggest that ADHD diagnosis is commonly overused and erroneously applied to children who skew on the “young” side of the class. Those born just before the state’s age-of-start cutoff date are 50 percent more likely to be diagnosed than those born just after. ADHD is an underlying neurological problem where incidence rates should not change dramatically from one birth date to the next. The researchers say that misdiagnoses may occur because a younger child might seem immature relative to the older kids in the class. They estimate that approximately 1.1 million children are affected by misdiagnosis. 

Read the report (pdf).