There has been a dramatic rise in the number of children being diagnosed with autism spectrum disorders (ASD), which has led to increased attention paid to assessment and intervention issues. This manuscript agrees with Camarata (2014) that the evidence base for early assessment and intervention should be expanded. However, it disagrees with Warren et al.'s (2011) assumption that there are not empirically validated early interventions. Reliable diagnosis has been documented during infancy and toddlerhood, and evidence suggests that the earlier the onset of intervention, the greater likelihood of an improved developmental trajectory. It is argued that early intervention is more cost and time efficient than a "wait and see" approach. With regard to published studies, the large amount of heterogeneity in the ASD population supports the use of rigorous single case experimental design research. It is an error to limit empirical evidence for treatments to only randomized clinical trials, which have the weakness of masking individual differences. Single case experimental designs examine the effects of intervention beyond typical maturation by allowing for clear estimations of developmental trajectories prior to the onset of intervention, followed by evaluation of the impact of the intervention. This commentary discusses the short- and long-term benefits of early diagnosis and intervention.