Traditional methods for the diagnostic assessment of autism spectrum disorders (ASDs), which have been increasingly adopted in the USA as prerequisites for both service eligibility and research participation, are expensive and difficult to acquire consistently in public health settings. Based on immediately available methodologies, we propose a cost-effective strategy for the assessment of children affected by ASDs, which would allow a shift in available resources toward treatment and could facilitate the acquisition of repeated-measures data, which is vital to the evaluation of response-to- intervention. As a test of principle, we examined the ability of clinicians to discriminate level of severity of autistic symptomatology among 65 ASD subjects using an adaptation of the Childhood Autism Rating Scale-2. Clinician's quantitative severity ratings reliably captured levels of gradation in severity ascertained independently using scores for current social impairment derived from the Autism Diagnostic Interview - Revised (r = 0.60), and exhibited item-level and scale-level inter-rater reliability on the order of 0.85. We conclude that standardized clinician ratings based on brief observation - without the need for extensive rater training - show tremendous promise for the rapid assessment of ASDs, especially when combined with ascertainment of developmental history and current symptomatology in daily social contexts.