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 .
Goal Attainment Scaling as an Outcome Measure in Randomized Controlled Trials of Psychosocial Interventions in Autism
Goal attainment scaling ( GAS ) holds promise as an idiographic approach for measuring outcomes of psychosocial interventions in community setting s. GAS has been criticized for untested assumptions of scaling level ( i.e. , interval or ordinal ) , inter-individual equivalence and comparability , and reliability of coding across different behavioral observation methods . We tested assumptions of e quality between GAS descriptions for outcome measurement in a r and omized trial ( i.e. , measurability , equidistance , level of difficulty , comparability of behavior sample s collected from teachers vs. research ers and live vs. videotape ) . Results suggest GAS descriptions can be evaluated for equivalency , that teacher collected behavior sample s are representative , and that varied sources of behavior sample s can be reliably coded . GAS is a promising measurement approach . Recommendations are provided to ensure method ological quality
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 .