Prevalence estimates of childhood autism and screening instruments (n = 18). Dots indicate prevalence estimates in reviewed studies. Horizontal lines indicate 95% CIs. Vertical line indicates pooled prevalence estimate in the meta-analysis. The heterogeneity among studies using the CABS and ABC is low. The pooled prevalence estimates of studies using the ABC as the screening instrument is the lowest, while those using the CHAT reported the highest prevalence. ABC, Autism Behavior Checklist; CABS, Clancy Autism Behavior Scale; CHAT, Checklist for Autism in Toddlers; CIs, confidence intervals.