For more than fifty years evidence has been accrued regarding the efficacy of applied behaviour analysis-based interventions for individuals with autism spectrum disorders. Despite this history of empirical evidence, some researchers and ASD experts still are reluctant to accept behavioral interventions as best practice for ASD. In this paper, we consider both random control trials and single subject experimental designs as forms of evidenced-based practice (EBP). Specific application of these methods to ASD research is considered. In an effort to provide scientifically based evidence for interventions for ASD, EBP standards have been debated without a consensus being achieved. Service users of ASD interventions need access to sound empirical evidence to choose appropriate programmes for those they care for with ASD rather than putting their hopes in therapies backed by pseudoscience and celebrity endorsements.