1. On 30 July 2025, the appellant, Jarrod Parkinson lodged an Application to Appeal Against the Decision of a Medical Assessor. The medical dispute was assessed by Dr Christopher Canaris, a Medical Assessor, who issued a Medical Assessment Certificate (MAC) on

30 June 2025. 2. The appellant relies on the following ground of appeal under s 327(3) of the Workplace Injury Management and Workers Compensation Act 1998 (the 1998 Act): * the MAC contains a demonstrable error. 3. The delegate is satisfied that, on the face of the application, at least one ground of appeal has been made out. The Appeal Panel has conducted a review of the original medical assessment but limited to the ground(s) of appeal on which the appeal is made. 4. Rule 128 of the Personal Injury Commission Rules 2021 (the PIC Rules) and Procedural Direction PIC7 - Appeals, reviews, reconsiderations and correction of obvious errors in medical disputes set out the practice and procedure in relation to the medical appeal process under s 328 of the 1998 Act. An Appeal Panel determines its own procedures in accordance with r 128(1) of the PIC Rules. 5. The assessment of permanent impairment is conducted in accordance with the SIRA NSW Workers Compensation Guidelines for the Evaluation of Permanent Impairment, 4th ed

1 March 2021 (the Guides) and the American Medical Association Guides to the Evaluation of Permanent Impairment, 5th ed (AMA 5). "WPI" is reference to whole person impairment. "Baseline WPI" is a reference to the total WPI assessed before deduction for the effect of pre-existing injury, condition or abnormality pursuant to s 323 of the 1998 Act. "Assessor" is reference to Medical Assessor".

1. On 12 June 2025 an amended referral was made to the Medical Assessor for a WPI evaluation caused by psychiatric and psychological disorders which occurred on

13 November 2023. 2. Mr Parkinson had been employed by the respondent as a pipe layer when on

13 November 2023 he was assaulted by a fellow colleague and subsequently developed a psychological disorder. 3. The Medical Assessor found 8% WPI.

1. The Appeal Panel conducted a preliminary review of the original medical assessment in the absence of the parties and in accordance with the Procedural Direction PIC7.
2. Mr Parkinson requested a re-examination but for the reasons given below, no error was found with the MAC.

1. The Appeal Panel has before it all the documents that were sent to the Medical Assessor for the original medical assessment and has taken them into account in making this determination.

1. The parts of the medical certificate given by the Medical Assessor that are relevant to the appeal are set out, where relevant, in the body of this decision.

1. Both parties made written submissions which have been considered below by the Appeal Panel.

1. The procedures on appeal are contained in s 328 of the 1998 Act. The appeal is to be by way of review of the original medical assessment but the review is limited to the grounds of appeal on which the appeal is made.
2. In Campbelltown City Council v Vegan [2006] NSWCA 284 the Court of Appeal held that the Appeal Panel is obliged to give reasons. Where there are disputes of fact it may be necessary to refer to evidence or other material on which findings are based, but the extent to which this is necessary will vary from case to case. Where more than one conclusion is open, it will be necessary to explain why one conclusion is preferred. On the other hand, the reasons need not be extensive or provide a detailed explanation of the criteria applied by the medical professionals in reaching a professional judgement.
3. Mr Parkinson appealed against the assessment in relation to the psychiatric impairment rating scale (PIRS) categories of self-care and personal hygiene and concentration persistence and pace.

1. In discussing Mr Parkinson's general health the Medical Assessor recorded:[1]

He admitted to past issues with mental health 'but it was manageable - I would get upset but it wasn't anything on a huge scale'. He admitted to 'depression but I've managed and there was one point when I was treated for about a month until I got better' and he thinks he may have been on mirtazapine although he could not recall clearly and it wasn't the dose that it is now.

He said he had been working steadily and had been so over the preceding year saying, 'In [sic] wouldn't skip a beat - I'd take extra shifts'. He was looking after himself showering, changing his clothes, and cooking daily as well as going to bed at a reasonable time getting to work. He went out socially and 'I would go out to the pub with my friends on a Friday night, I'd go to friends' houses, I'd have people here - I'd go out and explore." He had no issue with travel and was in weekly contact with his friends with whom he would hang out weekly. He had no difficulties with concentration."

1. In considering Mr Parkinson-'s activities of daily living the Medical Assessor recorded:[2]

"I asked after self-care. He 'can't work up the motivation to do anything - like shaving's a hassle - showering is a hassle - making my bed is a hassle - I generally keep the house clean'. He would shower '2 or 3 times a week if I have to leave the house to go shopping....' He changes his shirt every day or every 2 days as well as his underwear daily and shorts which he might change every 2 or 3 days. His appetite is 'little to none' but has gained weight. He would cook 'some nights' although 'I didn't for a while - I'm starting to get back into it."

1. The Medical Assessor recorded his findings on mental state examination at [5] the MAC:

"I interviewed the worker by Microsoft Teams. A good audiovisual connection was established. He was at his home in Wauchope. I saw his head and shoulders. He presented as a man of appearance consistent with his stated age wearing a baseball hat and T-Shire. His hair as it appeared from under his hat was dishevelled and he had an untidy beard. He had a nose piercing, a lip piercing, and bilateral piercings on his cheeks as well as earrings. He provided the history documented above. His narrative was coherent and consistent, but his manner of delivery was slowed with the ponderous quality with diminished facial expressivity and modulation of tone of voice all of which was consistent with a significantly restricted affect. I found no evidence of psychosis or of cognitive impairment."

1. In considering the evidence before him at [10C] the Medical Assessor noted that the expert retained by Mr Parkinson Dr Aman Suman, psychiatrist on 11 November 2024 had assessed a class 3 rating for Mr Parkinson's self-care and personal hygiene and for concentration persistence and pace.
2. The Medical Assessor said:[3]

"Comment: I rated the claimant as Class 2 for self-care and personal hygiene and concentration, persistence and pace which reflected the degree of improvement coinciding with his having stopped drinking."

1. Mr Parkinson referred to the accepted authority for the definition of demonstrable error.
2. As noted above Mr Parkinson appeals against the class 2 rating assessed in relation to the self-care and personal hygiene category of the PIRS and the category of concentration persistence and pace.

1. We were referred to the reasons given in the table 11.8 PIRS rating form by the Medical Assessor for his allocation of a class 2 rating. The descriptors for class 2 and class 3 were also kindly provided.
2. Mr Parkinson submitted that the facts as found were not indicative of a class 2 rating because he had been found to shower two to three times a week, only if he had to leave the house, and that he might change his clothes including his underwear every two to three days.
3. Mr Parkinson submitted that the Medical Assessor had not set out his actual path of reasoning as required in the often cited high court case of Wingfoot Australia Partners Pty Ltd v Kocak[4] that a Medical Assessor had to set out his actual path of reasoning.
4. We were referred to Sadsad v NRMA Insurance Limited,[5] AAI Limited v Fitzpatrick[6] as further examples of the principle.
5. Mr Parkinson submitted that the Medical Assessor had not adequately distinguished why he had chosen a class 2 over a class 3 rating.
6. It was, Mr Parkinson said, "incumbent on the Assessor to address the differences between these two classes". This was so particularly because his expert Dr Suman had found that the category had been assessed as a class 3 rating.
7. The "claimant's clearly articulated argument," it was contended, was that a class 3 rating was a more adequate assessment and that accordingly this "warranted the Assessor to deal with it".
8. We were referred to Dranichnikov v Minister for Immigration and Multicultural Affairs,[7] which concerned a different jurisdiction and the concept of natural justice under a different statutory scheme.
9. We were also referred to Rodger v De Gelder,[8] which was a motor vehicle case in which an Appeal Panel had failed to respond to a substantial argument based on evidence relied on by the claimant.

1. Mr Parkinson referred to the reasons given in the rating form again and emphasised the sentence "Comment: I noted his capacity to focus on the interview over the course of an interview of overline hours' duration." We assume that the word 'overline' was a typographical error for "over one" hour's duration.
2. In any event we were referred to Abdal v Insurance Australia Limited t/as NRMA Insurance[9] and a great deal of Wright J's judgment was reproduced. His Honor was dealing with a finding of another Medical Panel in the motor vehicle jurisdiction that "here were no overt cognitive difficulties noted during the assessment."
3. It was submitted that the Medical Assessor had made a similar error and Mr Parkinson argued that the capacity to focus during an interview was an irrelevant consideration and not a basis for the allocation of a class 2 rating.

1. The respondent referred to the relevant descriptors for this category, and noted that the Medical Assessor had explained his reasons adequately, including his reasons as to why he differed from Mr Parkinson's medicolegal expert psychiatrist, Dr Suman.

1. The respondent adopted the same approach to this issue, referring to the relevant descriptors and that the class 2 rating had been explained by reference to Mr Parkinson's improvement after he had stopped drinking. The respondent also referred to the observation by the Medical Assessor that Mr Parkinson had been able to focus on the interview with the Medical Assessor for more than an hour, which the respondent submitted was inconsistent with his submission that a class 3 rating was appropriate.

1. The PIRS is established as the rating system for assessing psychiatric/psychological impairment, by virtue of Chapter 11 of the Guides. Chapter 11.11 sets out six categories of behaviour to be considered when rating the behavioural consequences of a psychiatric disorder. Each category is divided into five classes, ranging in seriousness from 1 to 5. Class 1 relates to a situation where there is no psychological deficit, or a minor deficit attributable to the normal variation in the general population. Class 5 pertains to a person who is totally impaired.
2. Chapter 11.12[10] provides:

"Impairment in each area is rated using class descriptors. Classes range from 1 to 5, in accordance with severity. The standard form must be used when scoring the PIRS. The examples of activities are examples only. The assessing psychiatrist should take account of the person's cultural background. Consider activities that are usual for the person's age, sex and cultural norms."

1. The assessor is required to classify each category, and to apply the resulting scores as set out in Chapter 11.[11]
2. The assessment of psychiatric disorder has been considered in a number of cases. In Ferguson v State of New South Wales[12] Campbell J was concerned the case where the Medical Appeal Panel had revoked the MAC on the basis that the finding by the AMS had been glaringly improbable. His Honour found that the Panel had fallen into jurisdictional error. He said at [23]:

"By reference to NSW Police Force v Daniel Wark [2012] NSWWCCMA 36, the Appeal Panel directed itself that in questions of classification under the PIRS:

'... the pre-eminence of the clinical observations cannot be underrated. The judgment as to the significance or otherwise of the matters raised in the consultation is very much a matter for assessment by the clinician with the responsibility of conducting his/her enquiries with the applicant face to face'.

1. The Appeal Panel accepted that intervention was only justified: if the categorisation was glaringly improbable; if it could be demonstrated that the AMS was unaware of significant factual matters; if a clear misunderstanding could be demonstrated; or if an unsupportable reasoning process could be made out. I understood that all of these matters were regarded by the Appeal Panel as interpretations of the statutory grounds of applying incorrect criteria or demonstrable error. One takes from this that the Appeal Panel understood that more than a mere difference of opinion on a subject about which reasonable minds may differ is required to establish error in the statutory sense.
2. The Appeal Panel also, with respect, correctly recorded that in accordance with Chapter 11.12 of the Guides 'the assessment is to be made upon the behavioural consequences of psychiatric disorder, and that each category within the PIRS evaluates a particular area of functional impairment': Appeal Panel reasons at [37]. The descriptors, or examples, describing each class of impairment in the various categories are 'examples only': see Jenkins v Ambulance Service of New South Wales[13]. The Appeal Panel said 'they provide a guide which can be consulted as a general indicator of the level of behaviour that might generally be expected': Appeal Panel reasons at [37]."
3. In Glenn William Parker v Select Civil Pty Ltd,[14] another case regarding assessment of psychiatric disorder, Harrison AsJ cited [23] of Ferguson with approval at [65]. Her Honour said at [66]:

"In relation to Classes of PIRS there has to be more than a difference of opinion on a subject about which reasonable minds may differ to establish error in the statutory sense. (Ferguson [24])....."

"It was a matter for the clinical judgment of the AMS to determine whether the impairment with respect to employability was at the moderate level, as he did, or at some other level. But, in seeking judicial review, a mere disagreement about the level of impairment is not sufficient to demonstrate error of a kind susceptible to judicial review."

1. It is accordingly a useful approach for the Panel to enquire whether the assessment by the AMS in this category involved one of the following matters (to use the reference by Campbell J in Ferguson):

(a) if the categorisation was glaringly improbable;

(b) if it could be demonstrated that the AMS was unaware of significant factual matters;

(c) if a clear misunderstanding could be demonstrated, or

(d) if an unsupportable reasoning process could be made out.

1. In Lancaster v Foxtel Management[15] Basten AJ noted at [88-89] that these four considerations, although not inaccurate, were not a statement of legal principles, and that care should be taken in applying the explanation in place of s 327(3) and s 328(2).
2. With these preliminary observations, we now turn to the two issues raised by Mr Parkinson.

1. The relevant descriptors are contained in Table 11.1 of the Guides:

"Class 1 No deficit, or minor deficit attributable to the normal variation in the general population.

Class 2 Mild impairment: able to live independently; looks after self adequately, although may look unkempt occasionally; sometimes misses a meal or relies on take-away food.

Class 3 Moderate impairment: Can't live independently without regular support. Needs prompting to shower daily and wear clean clothes. Does not prepare own meals, frequently misses meals. Family member or community nurse visits (or should visit) 2-3 times per week to ensure minimum level of hygiene and nutrition."

1. The reasons given in the Table 11.8 Rating Form by the Medical Assessor for the class 2 rating were a copy of the relevant section of the body of the report which described

"I asked after self-care. He 'can't work up the motivation to do anything - like shaving's a hassle - showering is a hassle - making my bed is a hassle - I generally keep the house clean'. He would shower '2 or 3 times a week if I have to leave the house to go shopping ...'. He changes his shirts every day or every 2 days as well as his underwear daily and shorts which he might change every 2 or 3 days. His appetite is 'little to none' but has gained weight. He would cook 'some nights' although 'I didn't for a while - I'm just starting to get back into it'."

1. The basis of Mr Parkinson's submission was that the Medical Assessor had erred because he had ascribed the wrong rating to the facts that he had found. In view of the pre-eminence to be accorded to the clinical observations of the Medical Assessor during the consultation, such a submission, without more, amounts to no more than a difference of opinion on a subject about which reasonable minds may differ.
2. There was no demur to the facts found that Mr Parkinson showered two to three times a week, or that he changed his shirts every day or every two days, and his underwear every two to three days. Nor was there any challenge to the fact that he would cook on some nights. These matters are more in keeping with a class 2 rating. Moreover, Mr Parkinson lives by himself and is clearly able to live independently.
3. It may be accepted that the Medical Assessor was aware of the class descriptors he was dealing with, and was also aware that those descriptors were not strict criteria, but rather general examples with which, in his clinical judgement, he engaged to make the appropriate rating. We were referred to Wingfoot in a different context, but it is significant that the High Court discussed the function of a Medical Assessor at [47] (its reference to a Medical Panel is applicable also to a Medical Assessor)[16]:

"...The function of a Medical Panel is neither arbitral nor adjudicative: it is neither to choose between competing arguments, nor to opine on the correctness of other opinions on that medical question. The function is in every case to form and to give its own opinion on the medical question referred to it by applying its own medical experience and its own medical expertise."

1. Mr Parkinson argued that the above reasons were inadequate. It was alleged that the Medical Assessor had not adequately distinguished why he had chosen a class 2 rating over a class 3. With respect, Mr Parkinson was facing too high a premium on the standard of reasons that needs to be given. We were referred to some dicta from cases in the Motor Accidents Division as examples of what was said in Wingfoot. In Wingfoot, the plurality said at [48]:

"[48] The reasons that s 68(2) of the [Accident Compensation] Act obliged the Medical Panel to set out in a statement of reasons to accompany the certificate as to its opinion were the reasons which led the Medical Panel to form the opinion that the Medical Panel was required to form for itself on the medical question referred for its opinion. What is to be set out in the statement of reasons is the actual path of reasoning by which the Medical Panel arrived at the opinion the Medical Panel actually formed for itself."

1. In Vegan[17] Basten JA, McColl and Handley JJA agreeing, said at [122]:

" ... [T]o fulfil a minimum legal standard, the reasons need not be extensive or provide detailed explanation of the criteria applied by medical specialists in reaching a professional judgment: (authority omitted). At least, that will be so where the medical science is not controversial: if it is, a more expansive explanation may be required."

1. In applying the PIRS, the medical science is not controversial. As can be seen from the authorities referred to above, the PIRS is designed to be used by medical specialists in the assessment process, and accordingly the reasons not need to be extensive. There is no need for a Medical Assessor to explain in detail why a particular class was chosen and it is not incumbent on a Medical Assessor to address the particulars of the classes. As can be seen, the function of a Medical Assessor is to use his/her medical experience and expertise to resolve the medical dispute. There is also no obligation on a Medical Assessor to opine on the correctness of other opinions referred to him/her. Where there are unanimous opinions on both sides of the record, it may be that adequate reasons cannot be given without an explanation as to why that unanimity has not been adopted, however there is no such unanimity in this case.
2. The class 2 rating is confirmed.

1. Table 11.5 of the Guides provides the relevant descriptors:

"Class 2 Mild impairment: can undertake a basic retraining course, or a standard course at a slower pace. Can focus on intellectually demanding tasks for periods of up to 30 minutes, then feels fatigued or develops headache.

Class 3 Moderate impairment: unable to read more than newspaper articles. Finds it difficult to follow complex instructions (eg operating manuals, building plans), make significant repairs to motor vehicle, type long documents, follow a pattern for making clothes, tapestry or knitting."

1. The reasons given in the Table 11.8 rating form were again copied from the social activities segment in the body of the MAC:

"He said he feels foggy particularly in the mornings what with all his medication. He rates concentration as 'a struggle' saying, 'if I have a clear task, it's better but if I'm sitting there, it's no good - I've had 2 snakes escape because I've forgotten to close their doors... I think that sums it up a bit'. He does 'not really' read or watch TV though he might watch some TV 'once or twice a week and he could manage a movie length or half a movie length depending on the day'.

Comment**:** I noted his capacity to focus on the interview over the course of an interview of overline hours duration."

1. We have already indicated that the above comment contained a typographical error and indicated an interview of "over one hour's duration."
2. The decision in Abdal makes it clear that the comment by the Medical Assessor is not a relevant consideration in rating in this category. However, his reasons were not limited to this observation, which may be put to one side. No submissions were made regarding the reasons otherwise given, apart from a repetition of the argument that the Medical Assessor should have addressed specifically the reasons why he chose a class 2 rating over a class 3, which we have dealt with above.
3. Again, there is no demur to the finding that Mr Parkinson did "not really" read books or watch television although he watched either whole movies or half movies on television, "depending on the day". The Medical Assessor was entitled to draw his own conclusions, using his clinical experience, to judge the level of Mr Parkinson's ability to concentrate in the light of that apparent inconsistency.
4. Again, Mr Parkinson's submission is no more than an expression of a disagreement about which rational minds might differ.
5. For these reasons, the Appeal Panel has determined that the MAC issued on 30 June 2025 should be confirmed.

[4] [2013] HCA 43.

[5] 2014 NSWSC 1216.

[6] [2015] NSWSC 1108.

[8] [2015] NSWCA 211.

[9] [2025] NSWSC 478.

[11] See 11.15-11.21 at Guides page 65 and Table 11.7 at Guides page 66.

[12] [2017] NSWSC 887.

[13] [2015] NSWSC 633.

[14] [2018] NSWSC 140.

[15] [2022] NSWSC 929.

[16] See e.g. Western Sydney Local Health District v Chan [2015] NSWSC 1968 at [13].

[17] Campbelltown City Council v Vegan [2006] NSWCA 284.