Conclusions We found patchy evidence on reliability and validity , for only a few of the tools used to measure behaviour problems in young children with ASD .
Background Behaviour problems are common in young children with autism spectrum disorder ( ASD ) .
There are many different tools used to measure behavior problems but little is known about their validity for the population .
Objectives To evaluate the measurement properties of behaviour problems tools  used in evaluation of intervention or observational research studies with children with ASD up to the age of six years .
Effectiveness of a novel community-based early intervention model for children with autistic spectrum disorder.
The Nova Scotia  early intensive behavior intervention model -NS EIBI ( Bryson et al. , 2007 ) for children with autistic spectrum disorders was design ed to be feasible and sustainable in community setting s. It combines parent training and naturalistic one-to-one behavior intervention employing Pivotal Response Treatment - PRT ( R. Koegel & Koegel , 2006 ) . We followed 45 children ( 33 males , mean baseline age = 50 months ) for 12months . Mean gains of 14.9 and 19.5 months were observed on expressive and receptive language measures , respectively , for children with an IQ of 50 or more at baseline versus 6.1 and 8.4 months for children with IQs less than 50 . Behavior problems decreased significantly over the 1-year treatment for both groups , but autism symptoms decreased only for those with an IQ of 50 or more
Conclusions We found patchy evidence on reliability and validity , for only a few of the tools used to measure behaviour problems in young children with ASD .
Background Behaviour problems are common in young children with autism spectrum disorder ( ASD ) .
There are many different tools used to measure behavior problems but little is known about their validity for the population .
Objectives To evaluate the measurement properties of behaviour problems tools  used in evaluation of intervention or observational research studies with children with ASD up to the age of six years .