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 .
Randomized trial of intensive early intervention for children with pervasive developmental disorder.
Young children with pervasive developmental disorder were r and omly assigned to intensive treatment or parent training . The  intensive treatment group ( 7 with autism , 8 with pervasive developmental disorder not otherwise specified -- NOS ) averaged 24.52 hours per week of individual treatment for one year , gradually reducing hours over the next 1 to 2 years . The  parent training group ( 7 with autism , 6 with pervasive developmental disorder NOS ) received 3 to 9 months of parent training . The groups appeared similar at intake on all measures ; however , at follow-up the intensive treatment group outperformed the parent training group on measures of intelligence , visual-spatial skills , language , and academics , though not adaptive functioning or behavior problems .  Children with pervasive developmental disorder NOS may have gained more than those with autism
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 .