**6. Conclusions**

The application of the science of behaviour analysis has provided a range of evidence-based interventions to support individuals on the autism spectrum. Implementation and funding for these interventions differ widely across the world. They are typically home-, school-, or clinic-based, usually starting with a one-to-one therapist-to-child ratio and moving to group work as soon as possible. Outcomes have been very positive and social validity and satisfaction with the outcomes has been high.

This chapter offered a brief description of the scientific discipline of behaviour analysis, summarised the present state of knowledge around autism aetiology, diagnosis and prevalence, and focussed on applied behaviour analysis (ABA)-based interventions for children with autism. Finally, the requirements for professionals working in the field, i.e., Board Certified Behaviour Analysts (BCBA), were described.

Applied behaviour analysis-based interventions for autism clearly have a large evidencebase of effectiveness. The continued failure of governments across Europe to recognise this has left a vacuum, that all too often is filled by fads and fictions [57]. To avoid misinformation and ensure that these interventions are delivered with fidelity, well-trained staff are necessary. Parents of children with autism require and deserve the best information and supports available.

Although policy reform in the USA is still somewhat inconsistent across states and, yet, many are left without financial support, there is reason for optimism that offers a platform from which to lobby for further access to ABA-based interventions for all people with autism who need it.
