Study designs of evaluations included in the review
The authors state that studies with an experimental design allowing the identification of a causal relationship between intervention and reduction in problem behaviour were eligible for inclusion. The included studies used a single-subject design with non-blind observation.
Specific interventions included in the review
Studies of behavioural interventions were eligible for inclusion. The intervention procedures included were stimulus-based and instruction-based, and had single or multiple components. The components included extinction, reinforcement of appropriate behaviour, punishment and systems change. The interventions were tested in community and specialist settings; their duration ranged from 2 to 30 weeks.
Participants included in the review
Studies of children with autism and problem behaviour, aged less than 97 months old, were eligible for inclusion. The children in the included studies had mild to moderate intellectual disability. The majority were boys.
Outcomes assessed in the review
Studies that looked at reducing problem behaviour were eligible for inclusion. To be included, the studies had to provide 3 data points pre- and post-intervention. The problem behaviours measured in the included studies were tantrums, aggression, stereotypy and self-injury. The outcomes included in the review were the percentage reduction in problem behaviour and maintenance of the effect.
How were decisions on the relevance of primary studies made?
Three authors checked the identified studies for eligibility according to the inclusion criteria. To assess for inter-rater agreement, the 9 studies chosen for inclusion by the first author and 9 randomly-selected rejected studies were given to another author for re-assessment.