Although it's not hard to recognise a case of classic Kanner autism, there's far more disagreement about diagnoses for children with milder symptoms. As I argued on a Guardian blog, unless we have clear objective criteria for diagnosis, it's hard to compare one prevalence rate with another. The different numbers could just reflect local expertise, policy or practice in diagnosing autism.

-- Dorothy Bishop

from "Autism diagnosis and hyper-systemizing parents: Nottingham vs. Eindhoven"