Childhood Austism Spectrum Test (CAST)

Abstract

The Childhood Autism Spectrum Test (CAST), originally known as the Childhood Asperger’s Syndrome Test, is a widely used screening tool designed to identify symptoms of Autism Spectrum Condition (ASC), particularly in high-functioning children of primary school age. Developed by researchers at the University of Cambridge’s Autism Research Centre, including Simon Baron-Cohen, Fiona Scott, and colleagues (Scott et al., 2002; Williams et al., 2004), the CAST consists of 37 scored items plus an additional special needs section. It is typically completed by parents or primary caregivers and is intended for use in mainstream educational settings to facilitate early identification and subsequent clinical referral for detailed diagnostic assessment.

Keywords

Childhood Autism Spectrum Test, CAST, Asperger’s Syndrome, Autism Spectrum Condition, ASC, Screening, Primary School, Social Communication.

Authors

Fiona J. Scott, Simon Baron-Cohen, Patrick Bolton, Carol Brayne, J. Williams, C. Stott, C. Allison, F.E. Matthews

Purpose

The primary purpose of the CAST is to provide a quick, efficient, and cost-effective method for screening for potential Autism Spectrum Condition symptoms, including those associated with what was formerly termed Asperger’s Syndrome, in children attending mainstream primary schools. The goal is to identify children who exhibit a high number of characteristic behaviors indicative of ASC, thereby signaling the need for a comprehensive clinical evaluation. This early identification is crucial for accessing timely support and intervention services.

The scale was developed specifically for use in the UK context for children aged 4 to 11 years old. It acts as a gatekeeper, minimizing unnecessary clinical referrals while ensuring that children who genuinely require diagnostic assessment are prioritized. The instrument is freely available for non-commercial research and clinical use via the Autism Research Centre website.

Construct

The CAST measures behavioral traits associated with the core diagnostic criteria for Autism Spectrum Condition, focusing on the three main domains (or the ‘triad of impairments’):

• Social Interaction and Reciprocity: Items assess the child’s ability to engage in two-way conversations, understand social rules, make friends, and show concern for the peer group (e.g., items 1, 2, 10, 15, 29).
• Communication: Questions relate to language development, conversational skills, literal interpretation of language, and the use of unusual phrases (e.g., items 3, 7, 11, 30, 37).
• Restricted, Repetitive Patterns of Behavior, Interests, or Activities: This domain covers adherence to routines, intense or unusual interests, repetitive movements, and unusual attention to detail (e.g., items 6, 9, 14, 28, 34).

The instrument is designed to capture the subtle but persistent difficulties characteristic of ASC in children who may not have severe intellectual or language delays, thus targeting the population often missed by standard screening measures.

Validity

The validity of the CAST, particularly its test accuracy, has been rigorously studied (Williams et al., 2004). Studies have demonstrated strong psychometric properties, showing that the CAST effectively differentiates between children diagnosed with ASC and typically developing children.

Research confirmed that the CAST possesses high sensitivity and specificity when used with primary school populations. A cut-off score (typically 15 or above) was established to maximize the identification rate of children with ASC while maintaining a manageable false-positive rate. The scale’s ability to correctly identify cases was found to be comparable to other established screening measures, supporting its use as a preliminary diagnostic indicator.

Reliability

The reliability of the CAST has been investigated, demonstrating its stability over time. Williams et al. (2006) published findings specifically addressing the test-retest reliability of the instrument. The results indicated good consistency in scores when the instrument was administered to the same child’s parent/caregiver at different points in time.

This high test-retest reliability suggests that the behaviors reported by the parent are stable features of the child’s presentation, rather than transient states, lending confidence to the use of the CAST as a robust measure of enduring ASC traits. Further research has explored the consistency of ratings across different reporting sources (e.g., parents vs. teachers) as part of broader efforts to establish strong psychometric properties.

Factor Analysis

While the CAST was originally designed based on the clinical understanding of the ASC triad, factor analytic studies typically confirm that the items cluster into domains related to the core diagnostic criteria. Although specific detailed factor analysis results (e.g., confirmation of a two-factor or three-factor model) are not explicitly detailed in the original source content, the structure of the 37 scored items clearly reflects the domains of social interaction, communication, and restricted/repetitive behaviors, consistent with the foundational structure of Autism Spectrum Condition.

Subsequent research, including analysis of sex differences (Williams et al., 2008), has further explored how different item clusters function across demographic groups, suggesting that the underlying factor structure may require careful interpretation depending on the population screened.

Instrument

Test Type: Parent/Caregiver Report Screening Instrument

Format: 37 scored items (Yes/No response format) plus 2 non-scored items in a Special Needs Section. A score of 15 or higher suggests clinical referral.

Language Available: Primarily English (UK), though translations may exist for research purposes.

Population Group: Children in mainstream education settings.

Age Group: 4 to 11 years old (Primary School Age).

Population Details: Originally validated on UK mainstream primary school children, including those with and without clinical diagnoses of ASC and other developmental conditions.

Test Methodology: The caregiver or parent answers 37 questions relating to the child’s social, communicative, and behavioral patterns over the preceding months. Responses are scored dichotomously (Yes/No), and a total score is calculated. Interpretation relies on the established cutoff score.

Keywords

Screening tool, Social Communication, Repetitive behaviors, Early identification, Baron-Cohen, Developmental disorder, Psychometric properties.

Authors

Author ORCID Identifier: N/A (Information not provided in source material)

Affiliation Email addresses: N/A (Information not provided in source material)

Correspondence Address: N/A (Information not provided in source material)

Permissions & Fee and Test Year

The CAST instrument is hosted by the Autism Research Centre (ARC) at the University of Cambridge and is generally available free of charge for clinical and academic non-commercial use. The initial preliminary development and validation studies were published in 2002 (Scott et al.) and further accuracy studies were published in 2004 (Williams et al.), marking the primary years of the instrument’s establishment.

Reference’s

1. Scott, Fiona J., Baron-Cohen, Simon., Bolton, Patrick. And Brayne, Carol. (2002). The CAST (Childhood Asperger Syndrome Test): Preliminary development of UK screen for mainstream primary-school children Autism 6(1):9-31.

2. Williams, J., Scott,F., Stott, C., Allison, C., Bolton, P., Baron- Cohen, S. and Brayne, C. (2004). The CAST (Childhood Asperger Syndrome Test): test accuracy Autism, 9(1) :45-68.

3. Williams, J., Allison, C., Scott, F.J., Stott,C., Bolton, P.F., Baron-Cohen, S., Brayne, C.(2006). The Childhood Asperger Syndrome Test (CAST): Test-retest Reliability. 10(4): Autism 415-27.

4. Williams, J., Allison, C., Scott, F.J., Bolton, P.F., Baron-Cohen, S., Matthews, F.E., Brayne, C. (2008).The Childhood Autism Spectrum Test (CAST): Sex Differences. J Autism Dev Disord, 38(9): 1731-9.

Items of the Childhood Austism Spectrum Test (CAST)

IMPORTANT: The following scale items must be preserved in their original language and must not be changed in any way.

1. Does s/he join in playing games with other children easily?
2. Does s/he come up to you spontaneously for a chat?
3. Was s/he speaking by 2 years old?
4. Does s/he enjoy sports?
5. Is it important to him/her to fit in with the peer group?
6. Does s/he appear to notice unusual details that others miss?
7. Does s/he tend to take things literally?
8. When s/he was 3 years old, did s/he spend a lot of time pretending (e.g., play-acting being a superhero, or holding teddy’s tea parties)?
9. Does s/he like to do things over and over again, in the same way all the time?
10. Does s/he find it easy to interact with other children?
11. Can s/he keep a two-way conversation going?
12. Can s/he read appropriately for his/her age?
13. Does s/he mostly have the same interests as his/her peers?
14. Does s/he have an interest which takes up so much time that s/he does little else?
15. Does s/he have friends, rather than just acquaintances?
16. Does s/he often bring you things s/he is interested in to show you?
17. Does s/he enjoy joking around?
18. Does s/he have difficulty understanding the rules for polite behavior?
19. Does s/he appear to have an unusual memory for details?
20. Is his/her voice unusual (e.g., overly adult, flat, or very monotonous)?
21. Are people important to him/her?
22. Can s/he dress him/herself?
23. Is s/he good at turn-taking in conversation?
24. Does s/he play imaginatively with other children, and engage in role-play?
25. Does s/he often do or say things that are tactless or socially inappropriate?
26. Can s/he count to 50 without leaving out any numbers?
27. Does s/he make normal eye-contact?
28. Does s/he have any unusual and repetitive movements?
29. Is his/her social behaviour very one-sided and always on his/her own terms?
30. Does s/he sometimes say “you” or “s/he” when s/he means “I”?
31. Does s/he prefer imaginative activities such as play-acting or story-telling, rather than numbers or lists of facts?
32. Does s/he sometimes lose the listener because of not explaining what s/he is talking about?
33. Can s/he ride a bicycle (even if with stabilizers)?
34. Does s/he try to impose routines on him/herself, or on others, in such a way that it causes problems?
35. Does s/he care how s/he is perceived by the rest of the group?
36. Does s/he often turn conversations to his/her favorite subject rather than following what the other person wants to talk about?
37. Does s/he have odd or unusual phrases?

SPECIAL NEEDS SECTION

38. Have teachers/health visitors ever expressed any concerns about his/her development? If Yes, please specify…………………………………………………………………………….
39. Has s/he ever been diagnosed with any of the following: Language delay, Hyperactivity/Attention Deficit Disorder (ADD), hearing or visual difficulties, Autism Spectrum Condition (including Asperger’s Syndrome), A physical disability? Other (please specify)