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 .
Measurement Tools and Target Symptoms/Skills Used to Assess Treatment Response for Individuals with Autism Spectrum Disorder
This study examined the  measurement tools and target symptoms/skills  used to assess treatment response during Autism Spectrum Disorder ( ASD ) intervention trials from 2001 through 2010 . Data from 195 prospect i ve trials were analyzed . There were 289 unique  measurement  tools , of which 61.6 % were used only once , and 20.8 % were investigator- design ed . Only three tools were used in more than 2 % of the studies , and none were used in more than 7 % of studies . Studies investigated an average of 11.4 tool-symptom combinations per trial , with as many as 45 in one study . These results represent a lack of consistency in outcome measurements in ASD intervention trials . These findings highlight the need to set guidelines for appropriate outcome measurement in the ASD field
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 .