CAST: Childhood Autism Spectrum Test
A 37-item parent-report screening tool for autism spectrum characteristics in children aged 4–11. Designed for population-level screening; a score ≥15 indicates further evaluation is warranted.
About the CAST
The Childhood Autism Spectrum Test (CAST), originally called the Childhood Asperger Syndrome Test, was developed at the Autism Research Centre, University of Cambridge. It is a parent-completed questionnaire intended for use in community and school settings to identify children who may have autism spectrum characteristics.
The CAST was developed in response to the underidentification of autism in children who do not present with significant intellectual disability. It aims to capture the broader autism phenotype, including children whose social and communicative differences are subtle enough to go unrecognized in standard developmental checks.
The tool covers a broad range of behaviors across social communication, play, and routine domains, drawing on DSM and ICD criteria relevant to autism spectrum conditions.
What the Assessment Measures
The CAST evaluates autism-related characteristics across:
- Social and peer interactions, difficulty initiating or maintaining friendships, reduced interest in other children
- Communication, unusual language use, difficulty with conversational reciprocity
- Play and imagination, preference for solitary, repetitive, or rule-bound activities
- Routines and flexibility, insistence on sameness, distress at change
- Motor and sensory features, unusual sensory responses, motor stereotypies
Population and Format
- Ages: 4–11 years
- Respondent: Parent or primary caregiver
- Items: 37 yes/no questions
- Administration time: Approximately 10 minutes
- Setting: Community, school, or clinical screening
Scoring
The CAST yields a total score (range 0–31 scoreable items; 6 items are not scored).
Recommended cutoff (Scott et al., 2002):
- Score ≥15: Meets the screening threshold; warrants full diagnostic evaluation
- Score <15: Does not rule out autism spectrum conditions; clinical judgment is required
The CAST is intended as a screening tool only and does not provide a diagnosis. A positive screen should prompt a referral for comprehensive assessment.
Psychometric Properties
The CAST has been validated across multiple languages and cultural contexts:
- Good sensitivity and specificity at the ≥15 threshold in population-based samples
- Strong test-retest reliability in clinical and community settings
- Validated translations include Spanish (Morales-Hidalgo et al., 2017), Mandarin Chinese (Sun et al., 2013), and others
Clinical Considerations
- The CAST identifies children across the full autism spectrum, not only those with intellectual disability or classic autistic presentations
- Girls and children who mask autistic traits may score below the cutoff despite meeting diagnostic criteria; the CAST should be interpreted alongside direct observation and developmental history
- A negative screen does not preclude further evaluation if clinical concern remains
Who the CAST Is For
The CAST is appropriate when:
- A parent, teacher, or clinician has concerns about a child aged 4–11
- The clinical question involves autism spectrum characteristics, social communication difficulties, or restricted/repetitive behaviors
- Population-level or school-based autism screening is being conducted
References
- Scott FJ, Baron-Cohen S, Bolton P, Brayne C. (2002). The CAST (Childhood Asperger Syndrome Test): Preliminary development of a UK screen for mainstream primary-school-age children. Autism, 6(1), 9–31.
- Morales-Hidalgo P, Roigé-Castellví J, Vigil-Colet A, Canals J. (2017). The Childhood Autism Spectrum Test (CAST): Spanish adaptation and validation. Autism Research, 10(9), 1529–1540. PMID: 28383173
- Sun X, Allison C, Auyeung B, et al. (2013). The Mandarin Chinese version of the childhood autism spectrum test (CAST): test-retest reliability. Research in Developmental Disabilities, 34(10), 3267–3275. PMID: 23892873
- Sun X, Allison C, Matthews FE, et al. (2015). Exploring the underdiagnosis and prevalence of autism spectrum conditions in Beijing. Autism Research, 8(3), 250–260. PMID: 25952676
Frequently Asked Questions
How is the CAST scored?
The CAST contains 37 yes/no questions, of which 31 contribute to the total score (6 items are unscored). Each scored item counts as 0 or 1, giving a possible range of 0–31. Scoring is completed by the parent or caregiver and takes only a few minutes once the questionnaire is finished.
What does a CAST score of 15 or above mean?
A score of 15 or above meets the recommended screening threshold and indicates that a full diagnostic evaluation by a qualified clinician is warranted. Williams et al. (2005) reported 100% sensitivity and 97% specificity at this cut-point in a population-based UK sample. Reaching the threshold does not constitute a diagnosis of an autism spectrum condition.
Is the CAST self-report or clinician-administered?
The CAST is a parent-report instrument: a parent or primary caregiver completes it on behalf of the child. No clinician administration or specialized training is required for completion, though interpretation and any follow-up assessment should involve a qualified professional.
Can the CAST diagnose autism in a child?
No. The CAST is a population-level screening tool designed to identify children who may benefit from further evaluation, not to provide a diagnosis. A positive screen should prompt referral for a comprehensive multidisciplinary assessment using validated diagnostic instruments such as the ADOS-2 or ADI-R.
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