Overview
The Childhood Autism Spectrum Test (CAST; Scott, Baron-Cohen, Bolton, & Brayne, 2002) (formerly known as the Childhood Asperger Syndrome Test) is a parent questionnaire designed to screen for autism spectrum disorder among children aged 5 to 11 years. It was developed to be sensitive to autism spectrum conditions in the mainstream school population (i.e., for use predominantly in children with cognitive ability in the average range) (Scott et al., 2002). The instrument is a 37-item yes/no parent questionnaire; results yield a total score that can be compared to a cut-off score of 15. The CAST has been translated into many languages, and free downloads of all measures in all languages are available on the website included below the summary table.
Summary
Age: 5 years to 11 years
Time to Administer: Approximately 20 minutes
Method of Administration: Parent questionnaire of 37 yes/no items
Yields cutoff score
Subscales: N/A
Screening/Diagnosis: S
Autism Related Research
Williams, Allison, Scott, Bolton, Baron-Cohen, Matthews, & Brayne (2008)
Age Range: 4-9 years
Sample Size: 11,635
Topics Addressed:
Sex distribution of scores
Outcome:Williams, Allison, Scott, Bolton, Baron-Cohen, Matthews, & Brayne (2008)
The median CAST score was significantly higher in boys; moreover, there was a predominance of boys amongst those scoring > 15. Exclusion of children with ASD did not significantly affect results.
Conclusion: different profiles of social and communication skills in boys and girls must be taken into account when measuring these skills in the general population.
Allison, Williams, Scott, Stott, Bolton, Baron- Cohen, & Brayne (2007)
Age Range: 5–9 years
Sample Size: 73
Topics Addressed:
Test–retest reliability in a high scoring sample
Outcome:Allison, Williams, Scott, Stott, Bolton, Baron- Cohen, & Brayne (2007)
Agreement above and below the cut-point of 15, across administrations two months apart, yielded weak agreement (kappa = .41). Test-retest correlation was 0.67, however.
Conclusion: the CAST is a relatively robust screening tool for epidemiological research.
Williams, Scott, Stott, Allison, Bolton, Baron- Cohen, & Brayne (2005)
Age Range: 5–11 years
Sample Size: 1,925
Topics Addressed:
Validation of the CAST in a larger population sample
Outcome:Williams, Scott, Stott, Allison, Bolton, Baron- Cohen, & Brayne (2005)
CAST has good accuracy for use as a screening test, with high sensitivity (100%). However, it has low positive predictive value (50%), resulting in a high false positive rate. Test-retest reliability over a long period of time is strong; scores rarely increase over time, many decrease.
Conclusion: the CAST could be a useful screening test in epidemiological studies but it is not an appropriate general population screening in public health or educational settings.