Autism Spectrum Disorder in accordance to the Code of Fair Testing Practices in Education

Report to the Court

Assessment 4: Report to the Court: The Checklist for Autism Spectrum Disorder

Capella University


This paper serves the purpose of evaluating Checklist for Autism Spectrum Disorder in accordance to the Code of Fair Testing Practices in Education. The purpose of the assessment will be discussed, as well as, information pertaining to the test content, the domains tested and the information covered. Further discussion will occur on the is appropriateness of the assessment with regards to the test takers. This paper will discuss the materials provided in the assessment kit and how this pertains to current technology. Information relevant to the reliability and validity of the assessment will be presented. Finally, a summary discussing the overall usefulness, including both the strengths and weaknesses, of this assessment will be presented.

Keywords: assessment, evaluation, reliability, validity


According to the American Psychological Association, a professional within the psychological field must utilize an assessment method that has an established validity and reliability with the intended population being assessed (APA, 2016). The Checklist for Autism Spectrum Disorder (CASD) was developed as a quick and valid means for screening and diagnosing children suspected of having autism spectrum disorder, regardless of age, functioning level or IQ level (Stoelting Co., 2018). The CASD assessment aims to provide quick and accurate diagnostic distinctions of children with commonly mistaken diagnoses. The CASD is a comprehensive list of 30 symptoms, each associated with the occurrence of an ASD diagnosis (Mayes, 2012). The CASD is completed by utilization of a semi-structured interview with a child’s parent, through either information obtained from a teacher or child care provider and through direct observation of the child. The strengths of this assessment as pertaining to Element 1, lies in the ability of the assessment to be conducted through multiple means. This ensures the assessment can be completed in less time, ensuring earlier and quicker diagnosis.


According to the Joint Committee on Testing Practices (2004), a key consideration when selecting the correct assessment to utilize is to ensure the content within the assessment is appropriate for the intended purpose of engaging in the assessment process. As the intention of completing diagnostic assessment is to determine the appropriateness and likelihood of a diagnosis of ASD, information obtained through the assessment must provide the assessor with the means to make this determination. The CASD assessment is comprised of items referring to all core symptoms associated with ASD. Each symptom is grouped into six domains including: problems with social interaction, perseverative behavior, somatosensory disturbance, atypical communication and development, mood and problems with attention and safety (Mayes, 2012). A score is obtained through the completion of either a 20-minute semi-structured interview with parents, a teacher or child care provider familiar with the child or through direct observations of the child (Mayes, 2012). The CASD is the only diagnostic instrument designed to evaluate a single spectrum versus the assessing of different subtypes of pervasive developmental disorder and is able to accurately differentiate children with an autism diagnosis, versus children with other commonly misdiagnosed disorders, including Attention-deficit/hyperactivity disorder (Mayes et. al., 2009). Furthermore, as the CASD was developed through the decision-theory model (DTM), there is an emphasis on the determination of the appropriateness of a diagnosis versus the obtainment of a quantitative estimate (Cronbach & Gleser, 1965). The strengths of the CASD assessment within the domain of appropriateness is astronomical. The CASD is able to accurately determine the presence of an ASD diagnosis versus the occurrence of other commonly misdiagnosed disorders. This allows for the clients to receive the evidence-based interventions needed in an efficient manner.


According to the American Psychological Association, a psychological professional must utilize assessment methods that accommodate an individual’s language, situation, personal, linguistic, and cultural differences (APA, 2016). The CASD assessment is completed through the conduction of a semi-structured interview of either parents or a caregiver familiar with the child. This delivery method, allows for the administrator to individualize the language being used to allow for the responder to better comprehend the questions being asked. Currently, there is limited information available with regards to which languages the CASD has been successfully administered in. However, it is important to note that during the standardization process of the assessment, sample used was reflective of the ethnic and racial demographics of the USA (Mayes, et. al., 2014). Furthermore, the manual provided with the assessment kit, includes examples of both interviews, diagnostic reports and treatment plans for the assessor to utilize (Stoelting Co., 2018). A strength of this assessment as it pertains to materials, is the relative ease the assessment can be completed. As the assessment is comprised of a checklist, the assessor is able to complete the interview in a variety of environments. This allows for any potential effects a novel or clinical environment can have on the test subject to be mitigated altogether.

Training to Administer Assessment

While the CASD assessment can be completed by a parent independently, if being used as a diagnostic assessment, the CASD must be completed by a trained individual with a qualification level of C. Furthermore, the interviews and observations need to be conducted by a qualified psychologist or physician specialist who is familiar with ASD. This need for specialist and intensive training is a strength of this assessment. The CASD has been found to have a 100% diagnostic agreement between the score obtained by completion of the CASD and a psychiatrist using the DSM-IV (Mayes et al., 2013). In addition, the CASD has been found to be accurate when diagnosing individuals’ ranging from low functioning to higher functioning (Mayes et al., 2009).

Technical Quality

A key component to selecting the correct assessment is to ensure there is evidence of the technical quality, including the reliability and validity, of the assessment (Joint Committee on Testing Practices, 2004). A study completed by Mayes et. al. (2009), determined the criterion validity of the assessment in terms of differentiating children with a previously determined autism diagnosis, children with a diagnosis of Attention-deficit/hyperactivity disorder and neuro-typical children. It was determined that when completed, the CASD was able to accurately differentiate children with ASD and ADHD diagnosis, 99.5%. Furthermore, when compared to neuro-typical children, the CASD assessment was able to differentiate children with an ASD diagnosis 100% of the time (Mayes, 2009). An additional study, by Mayes, Black & Tierney (2013), determined the validity of the CASD assessment in diagnosing the occurrence of ASD across severity level, either low or high functioning. When compared to the Diagnostic and Statistical Manual of Mental Disorders- V (DSM-V), it was determined that the CASD was able to accurately determine severity level 93% of the time (Mayes, Black, & Tierney, 2013).

Another aspect of technical quality of an assessment is the reliability. At the present time, limited information is available with regards to the CASD. One study, by Mayes et. al., (2009), determined that when the checklist was completed independently by a clinician or parent, there was a 90% diagnostic agreement. This suggests that the CASD has a high interrater reliability rate (Mayes, 2009). While there is information pertaining to the validity of the CASD as a diagnostic tool, the minimal studies demonstrating the reliability of the assessment is a weakness. In order to ensure clinicians are utilizing assessments deemed best practice, it is of paramount importance that more studies be completed that seek to determine the reliability of the CASD.

Test Items, Format, Procedures and Modifications

The CASD assessment is a short 15 to 20-minute semi-structured interview, comprised of items referring to all core symptoms of ASD. Each symptom is grouped into six domains including: problems with social interaction, preservative behavior, somatosensory disturbance, atypical communication and development, mood and problems with attention and safety (Mayes, 2012). A score is determined following information obtained by parents, a teacher or childcare worker familiar with the child or through direct observation of the child. The score obtained aligns with a qualitative description, with a score of 15 to 30 suggesting the need for a diagnosis of autism, a score of 11 to 14 suggesting a potential diagnosis, a score of 8 to 10 suggesting an at-risk level, and a score of 7 or below suggesting the child is in neuro-typical range (Powell & Kuznetsova, 2014). Additionally, as the assessment is derived utilizing the DTM, the assessment can be completed through a flexible and changing approach. This allows the assessor to tailor the language utilized to accommodate the varying cognitive level of the responders. This flexibility is a strength of this assessment. Another strength of the CASD assessment within this domain is the scores are able to be obtained through interviews with not only parents, but staff and other caregivers familiar with the child (Mayes, 2012). This allows for the assessment to be completed in a brief time, a benefit in a busy clinical setting. However, this is also a potential weakness. As the assessment stresses the occurrence of any symptom, throughout the child’s life just not at present, is a positive indicator of the ASD diagnosis, this assessment may prove ineffective with children within the care system.

Group Differences

The CASD assessment was standardized against of sample of 1417 children, ages 1 to 18. Of this sample, 925 were categorized as neuro-typical, 437 children categorized as a non-ASD diagnosis and 55 children with an ASD diagnosis. According the Mayes, et. al, (2014) the sample used in standardization was representative of both the ethnic and racial demographics of the USA. Furthermore, the CASD was able to accurately determine the category group of the participants with a 99.5% accuracy rate (Mayes, 2012). This high rate of accuracy amongst a sample of racially and ethnically diverse demographics is a strength of the assessment, as it shows cultural differences do not have an effect on the results obtains.

Executive Summary

When determining the assessment to utilize within the clinical setting, it is important to analyze the assessment tool for the strengths and weaknesses. When analyzed against the guidelines put forth by the American Psychological Association and the Joint Committee on testing Practices, the CASD assessment is an exceptional test. The CASD provides a high diagnostic accuracy of 99.5%, when compared to the criterion presented within the DSM (Mayes, 2012). Furthermore, the CASD does not only rely on the current presence of symptoms when the individual is being assessed. This is of particular importance, as some of the symptoms associated with ASD occur at lower frequency as the child ages, making them difficult to directly observe (Mayes et. al, 2009). Another positive aspect of the CASD is the accuracy when determining the ASD diagnosis in individuals of varying severity levels (Mayes et. al, 2009). This allows for the assessment to have a high sensitivity rate.

Another strength of the CASD assessment, lies in the high validity rate when compared to other similar diagnostic tools. The CASD has undergone extensive studies to determine the accuracy of diagnosis when a co-occurring condition is present. These studies have found that the CASD is still able to accurately determine the ASD diagnosis in children demonstrating apraxia of speech and children with attachment-based disorders (Tierney et. al., 2015). This proves especially advantageous as children receiving diagnosis in a time-effective manner will have access to evidence-based interventions earlier in their development. Current studies have shown that access to early intervention positively alters a child’s long-term outcomes, achieves significant savings of support across the lifetime of the child, and will reduce the occurrence of secondary health and social complications (The Royal Australasian College of Physicians, 2013).

Another strength of the assessment lies in the means of assessment delivery. The CASD requires highly trained and specialized professionals to conduct the assessment for diagnostic purposes. This allows for the elimination of potential erroneous diagnoses. Furthermore, the CASD is able to be completed through a semi-structured interview format or through direct observation of the child. This flexibility allows for the assessment to be completed in a variety of environmental contexts. Furthermore, the checklist format of the assessment allows for the administrator to modify the language utilized within the interview to better suit the requirements and functioning levels of the respondents. However, it is important to note that this unstructured nature of the assessment could prove difficult for an inexperienced clinician, resulting in an interview that is disjointed and nonlinear (Atlas, 2017). Scoring following the administration of the assessment provides the assessor with a numerical score ranging from 1-30. Each score range is associated with a qualitative description indicating the likelihood of an ASD diagnosis. From this score, the assessor is able to provide the test taker with clear results and a potential treatment plan.

Finally, the CASD was standardized using a large and diverse sample size. This sample included children with confirmed ASD diagnoses, children with other commonly misidentified diagnoses and children with typical range. Children within the three diagnostic groups represented the current racial and ethnic demographics of the USA. Of these children, 99.5% were correctly placed within their diagnostic groups following the CASD. This high accuracy rate shows that the CASD is not adversely affected by any potential cultural differences of the test respondents.


The process of selecting an appropriate assessment requires a clinician to actively analyze and critique several areas. The assessor must ensure the assessment serves the intended purpose and is applicable to the population it is being utilized with. The assessment must allow for ease of administration and provide modifications for individuals who may not be able to access the assessment in its current form. Furthermore, a clinician must ensure the assessment demonstrates validity and reliability to ensure best practice. With this aforementioned information in mind, it is my recommendation that that CASD assessment continue to be utilized. The CASD demonstrates flexibility and ease of use which is beneficial in an ever-changing health field. However, it is important to note that research aimed at determining the reliability of the assessment and efficacy with multicultural communities be conducted to ensure the CASD remains the standard of ASD diagnosis.

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