To assess the effect on prevalence estimates of using different algorithms to identify children with attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) in healthcare data. Three algorithms were developed and run on administrative/research data in Finland, France (Haute Garonne), Italy (Emilia Romagna), Norway and Wales: (1) ≥ 1 ADHD or ASD diagnoses recorded in specialist settings, (2) ≥ 2 ADHD or ASD diagnoses recorded in primary care and (3) ≥ 1 prescription for…
