From the abstract: "We found five relevant studies, which lasted between 24 months and 36 months. Of the five studies, three were conducted in the USA and two in the UK. Only one study randomly assigned children to a treatment or comparison group, which is considered the 'gold standard' for research. The other four studies used parent preference to assign children to groups. A total of 219 children were included in the five studies; 116 children in the EIBI groups and 103 children in generic, special education services groups. All children were younger than six years of age when they started treatment; their ages ranged between 30.2 months and 42.5 months. These studies compared EIBI to generic, special education services for children with ASD in schools. [We] found weak evidence that children receiving the EIBI treatment performed better than children in the comparison groups after about two years of treatment on scales of adaptive behavior, intelligence tests, expressive language (spoken language), and receptive language (the ability to understand what is said). Differences were not found for the severity of autism symptoms or a child's problem behavior. No study reported adverse events (deterioration in adaptive behaviour or autism symptom severity) due to treatment..."