A technology assessment report 1 on behavioural interventions for preschool children with autism was abstracted in the Health Technology Assessment Database 2. Findings of existing studies, though limited, suggest that preschool children with autism exhibit cognitive and functional improvement when receiving behavioural intervention with applied behavioural analysis for approximately 20 hours per week or more. It is not clear, however, which subset of children with autism derive the most benefit, which components of therapy are integral to positive outcomes, whether similar results would be observed in older children with autism, whether there are definable long term functional benefits, or whether reported gains in IQ translate into happier people with greater functioning in the community.