By convenor |

The DSM-5 and the NDIS treat severity ratings for autism/ASD quite differently.

The DSM-5 (2013) and its update, the DSM-5-TR (2022), associate severity ratings with a diagnosis of Autism Spectrum Disorder. 

A challenge with severity ratings in an autism diagnosis is that the rating scale is too vague. Level 1 means "Requiring support" while Level 3 means "Requiring very substantial support". But interpretations vary: some people think an autistic person who needs help with hygiene every time they use the toilet does not need "very substantial support" when they know autistic people who don't use the toilet at all. Others feel that an autistic person who fails to remain in a job for more than 6 months requires "very substantial support" to accommodate them in a work place. Interpretations vary widely as to what autism severity ratings mean, even among experienced clinicians ... which is presumably why the DSM-5 says "severity categories should not be used to determine eligibility for and provision of services". 

The autism spectrum is very poorly understood.

A proper DSM-5 autism diagnosis has two severity ratings, not just one. The DSM-5-TR diagnostic criteria for ASD (see say that a severity rating must be specified for each of Part A and Part B of the diagnostic criteria.

Each of the severity ratings is 1, 2 or 3. So an autistic person’s DSM-5 diagnosis report might specify severity level 2 for Part A of their diagnosis, while they have severity 1 for Part B. Overall, there are 9 combinations of the severity ratings.

The NDIS, on the other hand, developed its computer systems to only accept one severity rating in the range 1 to 3. The following figure shows what this means for the NDIS’s recording of participant’s ASD diagnoses.






NDIS Levels





NDIS Level 1





NDIS Level2





NDIS Level 3

The figure shows that only one of the nine DSM-5 combinations, the 1/1 pair, is recorded as NDIS ASD Level 1 while 5 of the nine DSM-5 categories (more than half of the categories) are recorded as NDIS ASD Level 3, the most severe rating in the NDIS categories. The most severe DSM-5 rating 3/3 is only 1 of 5 severity ratings in the NDIS ASD Level 3 category.  

Note that NDIS Level 3 ASD (which is not a DSM-5 category) apparently means "needs substantial support" in relation to some aspects of a person's autism ... which is different from the DSM-5 Levels 3/3 that means "needs substantial support" for most or all aspects of their autism. NDIS ASD Level 3 is a very broad category that covers more than half of the categories in the autism spectrum. The DSM-5 Levels 3/3 category is much smaller, more severe and unrecognised: it consists mostly of people who cannot self-advocate so their voices are unheard and their needs are unrecognised and ignored. 

NDIA Board Chair, Helen Nuggent (left), Bob Buckley, A4 Convenor (centre), Mr Rob de Luca, NDIA CEO (right)

At a meeting, the NDIA CEO and the Board Chair told A4’s Convenor, Mr Bob Buckley that:

  • when the NDIS is given a diagnostic report with two severity ratings, they take the higher of the two as the value they recorded for the participants; and 
  • the NDIA would change its computer systems to capture the two severity levels as well as the other information that is part of the DSM-5 (at the time) ASD diagnosis report.

The NDIA has not made these changes to its computer systems.

Other information in a complete DSM-5 ASD diagnosis report includes:

  • with/without intellectual impairment
  • with/without language impairment
  • and several other items

The NDIA’s computer system can record a secondary disability that could be recorded as Intellectual Disability … but the Scheme Actuary reports that the information held in this field in the database is unreliable and inconsistent. Published data from the NDIA suggests there are few if any records of “with language impairment” associated with autistic participants despite many of them reporting they are non-verbal. 

A major concern from the a largely ignored part of the autism sector is that the way that the NDIA records ASD severity means that the autistic NDIS participants with the most severe presentations, ASD Levels 3/3 with both intellectual and language impairment, are hidden among participants with significantly less severe ASD presentations. 

The NDIA has been challenged on this issue on multiple occasions but it chooses to ignore it; it refuses to act. In this way, its managers wilfully ignore many serious needs of the most severely autistic participants, some of the people the NDIS was most intended to help. 

The NDIA targets some of the most vulnerable young NDIS participants through its extremely cruel ABA policy - see This NDIA policy targets recently-diagnosed children with the most severe autism often before their parents come to properly appreciate the challenges they face in trying to understand their child and advocate effectively for their child’s support needs.  The NDIA and the AAT need to substantially improve their attitudes and approach to the autism sector. The disrespect and contempt that both currently show to autistic Australians, their carers, specialist clinicians and disability advocates is utterly unacceptable. 

The NDIA relies increasingly on automated systems to develop Statements of Participant Support, that are the bases for participants’ NDIS Plans. This means the NDIA increasingly relies on incomplete and often misleading information in its plan development process. The result is increasingly inappropriate NDIS Plans for autistic NDIS participants, which increases support cost in the long-run - the NDIA’s own approach to autism supports undermines Scheme sustainability. 

The NDIA’s persistent use of PEDI-CAT assessments for autistic NDIS participants, when they have been repeatedly chastised for this practice, is another example. Clearly, the NDIS does not listen to evidence-based advice and certainly does not act on it. The NDIA’s management does not achieve  effective continuous improvement. 

The NDIA could conduct a small experiment to assess whether data from ASD diagnoses might be more helpful than the PEDI-CAT assessments that it currently uses. 

The NDIA has expressed concern about the quality of ASD diagnoses, yet it does nothing to improve the quality. The NDIA could easily improve the quality of ASD diagnoses in Australia. It could easily contact any clinician who provides a substandard ASD diagnosis, such as required items missing from the diagnosis report, by insisting on a complete report from clinicians. It could easily record the date of diagnosis to report on where in the country diagnoses are delayed. It could work with the autism sector on improving severity ratings and progress measures. It could consider how its data can inform programs to improve support advice and decisions. 

The clear conclusion from this is that the government and the NDIA don't want to improve outcomes for autistic Australians. Instead, they want proposed changes to the NDIS legislation that will remove many autistic Australians from the NDIS which leaves them with nowhere to go for essential support. The federal government’s excuse is that they want the state/territory governments to support autistic Australians despite the overwhelming evidence that the state/territory governments have never succeeded in providing adequate services and supports for their autistic citizens. It is not enough that all state/territory governments fail to deliver education and health services for autistic Australians; the preferred model is that autistic Australians should be denied the NDIS, which despite many failings is often the best available option for them. 

The NDIS would do far better if it:

  1. worked with autistic people (and those with lived experience), researchers, and clinicians to develop more objective severity ratings to help administer services and supports; and

  2. properly recorded autism data then, together with the autism sector, analysed the collected data to inform and improve policy, programs and supports for autistic NDIS participants. 

Bob Buckley, A4 Convenor