A recent Stanford study contains a small, easily overlooked detail that is often overlooked in between budget hearings and policy memos. A child born a few weeks prior to a state’s preschool cutoff date has a much higher chance of receiving a diagnosis of ADHD, a speech disorder, or a vision or hearing issue than a child born shortly after. same family earnings. same area. The same challenges, frequently. Whether or not they entered a classroom a year earlier is the only real distinction.
Researchers at Stanford’s Institute for Economic Policy Research came to that conclusion after spending time reviewing Medicaid records from 32 states. Aileen Wu, Adrienne Sabety, and Maya Rossin-Slater weren’t attempting to make a dramatic political statement. They were attempting to comprehend something more straightforward: why diagnosis rates increase when children enter institutional settings and whether this trend begins earlier than previously thought.
Yes, it does. Compared to children who have not yet entered a classroom, children who start public preschool at age three or four are diagnosed with ADHD, hearing or vision issues, and speech or language disorders at significantly higher rates. The increases are significant: among children born shortly before the enrollment cutoff, speech and language diagnoses increased by nearly 9%, hearing and vision problems by nearly 15%, and ADHD by nearly 17%. It’s difficult to read that without thinking about all the parents who thought their toddler was just “shy” or “stubborn,” when a trained eye in a classroom might have seen something completely different.
What follows the diagnosis is what sets this study apart from many other studies in education. These are not merely labels that are distributed and then forgotten. Children with diagnoses were more likely to receive treatment, and their families were more likely to be connected to resources that they might not have otherwise been aware of. It turns out that a preschool teacher can serve as an unofficial referral system by pointing a parent in the direction of a pediatrician or specialist when they see a child not responding to his name or having trouble forming sentences that other three-year-olds can do with ease.
Researchers have long recognized a pattern in kindergarten: the youngest students in a class are flagged for behavioral issues much more frequently than their older peers. No one could clearly explain why. According to this study, the pattern actually begins earlier, in preschool, and spending more time in a structured environment—rather than merely being compared to older peers—is largely responsible.
When it comes to the practical implications of this, Sabety has been quite straightforward. She contends that early childhood is a window of opportunity that is important for the diagnosed child as well as the entire family. Given that the current administration is threatening to cut funding for Head Start, a federal program that serves about a million low-income children annually, as well as more general efforts to completely dismantle the Department of Education, that argument is particularly compelling at this time.
Sitting with the asymmetry here is worthwhile. Reducing preschool funding results in more than just fewer children learning their letters a year ahead of schedule. This research suggests that for families who might not have another reliable point of contact with the healthcare system, it probably means delayed diagnosis, treatment, and support. Compared to the costs typically discussed in budget fights, that one is quieter, but it might be more long-lasting.
Preschool isn’t intended to be a medical screening tool, and no one involved in the study is making any claims to the contrary. However, there is a plausible argument that it operates as one in any case—almost unintentionally—just because skilled adults spend hours each day closely observing kids. It remains to be seen if policymakers will balance that unintentional benefit against the cost of public preschool programs.
