The entry to kindergarten is one of the most memorable and important milestones in a child's school career. Positive and quality kindergarten experiences have been associated with meaningful outcomes sustained into adulthood including greater rates of college attendance/higher earnings. Kindergarten entry is one of the first educational transitions made by a family, and it may cause stress and present new challenges for children and families. Given the increased demands that are associated with school entry and the concerns parents may have about this developmental milestone, there are numerous popular press and policy recommendations (e.g., National Association for the Education of Young Children), as well as empirical papers, that weigh in on the appropriate age to start kindergarten.

The transition to kindergarten is of particular concern for parents of children with ADHD, especially those relatively young for the grade. There is converging evidence suggesting that children who are young for their kindergarten class (e.g., they have a birthdate that falls within the months immediately preceding the cut-off date, typically August through November) are at increased risk for a range of negative educational outcomes including lower academic achievement, grade retention, social impairments, and ADHD diagnosis . These risks appear to be related to age of entry when other explanatory variables are controlled. Thus, these studies suggest that the robust evidence that children closest to an arbitrary cut-off date are disproportionally at-risk for negative social, behavioral, and educational outcomes is solely a consequence of educational policy - a phenomenon called the Relative Age Effect (RAE). Together, the consequence of these risks are 1.5x increased ADHD diagnostic rates and increased ADHD treatment with psychoactive medication for children relatively younger for their kindergarten grade .

There are prominent, candidate mechanisms that may explain the differential risk for children with ADHD who are also young for the grade. First, if a teacher is basing behavioral expectations for children in the classroom based on the relatively older children in the class, children who are relatively younger and have behaviors that are attributed to having considerable delays, even in situations where the child is acting in a manner consistent with their chronological age. Over time, if teachers are issuing frequent commands/reprimands, a coercive process may develop. Second, given expected variability in neurocognitive processing at this age level, inappropriate demands may fail to facilitate, and potentially even slow, the development of executive functions. The present proposal aims to reduce functional impairments and ADHD symptom levels by investigating whether evidence-based school treatment for ADHD (e.g., positive behavior supports) coupled with teacher training on the RAE results in improved school functioning for children with elevated ADHD symptoms prior to the kindergarten year. Further, the potential mechanism for the impairment experienced by children with ADHD will be explored, by investigating whether the impairments are due to characteristics of the child (e.g., deficits in neurocognitive development), the classroom (e.g., teacher classroom management strategies), or both.