DETERMINATION OF APPEAL PANEL	
	
CITATION:	Camden Council v Harle [2022] NSWPICMP 339	
		
APPELLANT:	Camden Council	
		
RESPONDENT:	Carolyn Harle	
		
Appeal Panel:	Member John Wynyard
Medical Assessor Patrick Morris
Medical Assessor Michael Hong 	
		
DATE OF DECISION:	23 August 2022	
		
CATCHWORDS: 	wORKERS cOMPENSATION -   Appeal against section 323 of the Workplace Injury Management and Workers Compensation Act 1998 (1998 Act) deduction of 1/10th; whether reliance on statutory presumption of section 323(2) of the 1998 Act erroneous; whether the Medical Assessor (MA) gave adequate reasons; whether MA applied incorrect test; Held — MA failed to consider large body of evidence that showed worker was already under psychiatric care when she commenced employment; MA made error of fact and applied incorrect criteria in applying  the statutory 1/10th deduction pursuant to section 38(2) of Workers Compensation Act 1987 as no shortage of medical evidence already before him as to the pre-existing condition which was at odds with the 1/10th assessment; MA failed to give adequate reasons as to the deduction accordingly; Western Sydney Local Health District v Chan and Campbelltown City Council v Vegan applied; MA applied wrong test in considering whether the employment injury had significantly aggravated the worker’s pre-existing condition rather than determining whether the pre-existing condition had itself caused a deductable impairment; Ryder v Sundance Bakehouse applied; Held — Medical Assessment Certificate revoked; consideration of tension between section 323 of the 1998 Act and Chapter 11.10 of the Workers Compensation Guidelines (Guidelines); written submissions called for; Marks v Secretary, Department of Communities and Justice (No 2), Cole v Wenaline Pty Ltd, Elcheikh v Diamond Formwork (NSW) Pty Ltd and Ryder v Sundance Bakehouse Pty Ltd considered; Chapter 11.10 of the Guidelines found to be inconsistent with section 323 of the 1998 Act; section 323(1) of the 1998 Act applied and deduction increased to 20%. 

BACKGROUND TO THE APPLICATION TO APPEAL
1.	On 17 December 2021 Camden Council, the appellant, lodged an Application to Appeal Against the Decision of a Medical Assessor. The medical dispute was assessed by 
Dr Christopher Bench, a Medical Assessor (MA), who issued a Medical Assessment Certificate (MAC) on 22 November 2021.
2.	The appellant relies on the following grounds of appeal under s 327(3) of the Workplace Injury Management and Workers Compensation Act 1998 (1998 Act): 
•	the assessment was made on the basis of incorrect criteria,
•	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.	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 the PIC Rules.
5.	The assessment of permanent impairment is conducted in accordance with the NSW Workers Compensation Guidelines for the Evaluation of Permanent Impairment, 4th ed, reissued 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.
RELEVANT FACTUAL BACKGROUND
6.	On 23 August 2021 this matter was referred to an MA for an assessment of WPI caused by a psychiatric/psychological disorder that occurred on 22 August 2018. 
7.	The respondent worker, Ms Carolyn Harle, was employed as a Corporate Reporting and Planning Officer. The MA said:
“The applicant noted she commenced employment on a part-time basis at Camden Council in September 2016 and subsequently took up a permanent full-time position in December 2016. She denied being the subject of any work performance or disciplinary issues prior to the work injury.
At the time of the work injury, the applicant was under the psychiatric supervision of her psychiatrist, Dr Mark Cross. She was being treated with the anti-depressant Cymbalta. She was also in psychotherapy with Emma Slawitchka.”
8.	We note the evidence of Ms Robyn King, the Senior Work Health & Safety Advisor with the employer, that the date Ms Harle commenced employment was 19 September 2016. Ms Harle ceased work on 30 September 2018.
9.	Ms Harle was injured by being bullied and harassed at her workplace.
10.	The MA assessed 19% WPI, from which he deducted 1/10th pursuant to s 323(2) of the 1998 Act.
PRELIMINARY REVIEW
11.	The Appeal Panel conducted a preliminary review of the original medical assessment in the absence of the parties.
12.	The appellant employer did not apply to have the worker re-examined by a MA who is a member of the Appeal Panel. The issue concerned the application of s 323 of the 1998 Act, and all relevant material was before us. Accordingly, a re-examination was not indicated.
EVIDENCE
Documentary evidence
13.	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. 
Medical Assessment Certificate
14.	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. 
SUBMISSIONS 
15.	Both parties made written submissions which have been considered by the Appeal Panel. 
FINDINGS AND REASONS 
16.	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. 
17.	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.
18.	The appellant employer relied on one ground of appeal, submitting that the MA had fallen into error by assessing a 1/10th deduction. 
The MAC
19.	The MA referred to Ms Harle’s prior psychiatric history and said:
“The applicant stated her first mental health contact was in 2016. The collateral materials were reviewed with the applicant. Dr Mitchell had noted the applicant having suffered anxiety and depression since 2007, and Dr Khan had prepared a Mental Health Care Plan in 2008 for anxiety and depression and referred her to a psychologist. The applicant noted she has only a very vague recollection of this episode. She reported having seen a psychologist for a few sessions, "then I was all good". She was unable to further elaborate on this mental health contact.
In 2016, she was suffering “anxiety and depression … I got sick when I was in America. I had bleeding of the bowel, and I had to go to Boston Hospital … I knew there was an ICAC investigation regarding Paramatta” (Council). She had severe anxiety associated with gagging and shortness of breath. She was sad, with decreased appetite and weight loss. She was tearful. "I didn't want to do anything". She had particular difficulties with insomnia. "I wasn't sleeping at all … I'd wake in the early hours of the morning". She had difficulties with lethargy and passive suicidal ideation. "I didn't want to be here". She denied having had any active suicidal ideation, plan or intent. She attended Campbelltown Hospital. She was unsure of the diagnosis. She was not admitted. She was subsequently admitted to Northside Macarthur under Dr Cross for a period of ten weeks. She was diagnosed with anxiety and depression. She was treated with the anti-depressant valdoxan however was unable to tolerate it and commenced on Cymbalta. She remained on Cymbalta at the time of the work injury.
On review, the applicant denied having ever suffered any other episodes of depression.
She denied any history consistent with past episodes of hypomania or psychosis. She denied any history consistent with past episodes of Obsessive-Compulsive Disorder.”
20.	The MA also took a history of repeated sexual assault when Ms Harle was around six years old. A traumatic childhood was noted.
21.	The MA said:
“She noted the onset of re-experiencing phenomena during her first admission to
Northside Macarthur in 2016 “it only started to raise its head when I went to Northside Macarthur". She had the onset of nightmares. She would awaken, panicked and short of breath. She had intrusive thoughts and images associated with psychological distress, increased heart rate and shortness of breath. She was easily startled. She noted being hypervigilant as a child “I was always worried”. She had difficulties with positive emotions and significant preoccupation with negative emotions, including shame and embarrassment. She avoided thinking or talking about the trauma. She engaged in a lot of distraction, especially her work, in order to avoid being reminded of the trauma. She was first diagnosed with Posttraumatic Stress Disorder by Dr Mark Cross. Her psychologist Emma Slawitchka also diagnosed Posttraumatic Stress Disorder. She has subsequently been diagnosed with Complex Posttraumatic Stress Disorder.”
22.	In his opinion at [10a], the MA said:
“As noted above, the applicant had been diagnosed with Posttraumatic Stress Disorder during a psychiatric admission during Northside Macarthur in 2016. She had engaged in psychotherapy with Emma Slawitchka, who had similarly diagnosed Posttraumatic Stress Disorder. There was significant evidence during the clinical evaluation, and collateral materials to support the work injury has caused a significant aggravation of her Posttraumatic Stress Disorder, and as such, it is the evaluator's opinion there is a 1/10th deduction indicated for a pre-existing condition.”
23.	In dealing with the reports before him at [10c] of the MAC, the MA conducted a limited survey of the evidence before him. He referred to: 
•	Ms Harle’s statement of 16 April 2019;
•	“letter” from Ms Slawitchka dated 25 October 2016;
•	“letters” from Dr Mark Cross dated 7 July 2018, 12 October 2018, 26 October 2020 and 10 July 2021;
•	Workcover certificates;
•	reports from Dr Richa Rastogi dated 2 December 2020;
•	clinical records of Ms Slawitchka;
•	care plan by Dr Renae Mitchell dated 5 July 2018, 12 February 2020, 15 February 2017, and 24 August 2018;
•	“session notes” from Ms Schuldt dated 22 February 2020, 7 March 2020 and 20 March 2020;
•	Allied Health Recovery Request dated 27 July 2020;
•	clinical notes of Schwartz Family Practice from 18 May 2016;
•	Dr Danish Khan mental health plan dated 31 August 2008;
•	Dr Christopher Canaris report dated 27 May 2019;
•	Dr Leonard Lee reports dated 11 March 2019 and 19 February 2021;
•	“letter” dated 29 September 2020 from Mr Thomas O’Neil.
24.	Relevantly, when considering the report of Dr Lee dated 19 February 2021, in which a 50% deduction was advised, the MA said:
“Dr Lee completed a Psychiatric Impairment Rating Scale noting a whole person impairment of 18%, for which he deducted 50% "on the basis of uncorroborated evidence and evidence of unreliable reporting". (Comment: It is noted there is no such allowance for a deduction in the WorkCover Permanent Impairment Guidelines….)”.
25.	At paragraph [11] of the MAC there are three templated questions regarding impairment caused by pre-existing conditions. The MA stated that Ms Harle was suffering from a pre-existing “Psychiatric / psychological disorder (Posttraumatic Stress Disorder) which directly contributed to the worker’s “Anxiety, depression, impaired concentration, symptoms of panic. Insomnia and lethargy.” The extent was said to be “difficult or costly to determine” and, applying the provisions of s 323(2), one tenth was deducted.
SUBMISSIONS
Appellant employer
26.	The appellant employer referred to evidence that was before the MA that indeed confirmed the view that there was a pre-existing psychological condition. It referred to a report from Ms Harle’s treating psychiatrist, Dr Mark Cross dated 8 September 2016, in which Dr Cross noted symptoms, including a mild tremor from her medication, which worsened when Ms Harle was anxious. It had been triggered when Ms Harle attended her first session with her psychologist. 
27.	We were referred to the report of Ms Harle’s treating psychologist, Emma Slawitchka of 25 October 2016 in which Ms Slawitchka related that Ms Harle presented with symptoms of anxiety, panic and depression through psychological stressors. Ms Slawitchka took a history of a “recent” admission to Northside Macarthur for 10 weeks. Ms Slawitchka reported that Ms Harle was coping with working three days per week with the appellant employer, and that family conflict had caused an increase in her anxiety, with distressing memories about her past beginning to emerge. 
28.	The appellant employer referred to a further report by Dr Cross of 13 December 2016 in which Dr Cross reported that Ms Harle was experiencing an increase in nightmares and was tearful about certain memories returning. 
29.	We were also referred to clinical notes by Dr Maryanne Nicholas dated 12 December 2016. The entries noted that Ms Harle was:
“coping a bit better
still getting nauseated
seeing psychologist reg-brought some trauma from her childhood
….”
30.	The appellant employer also referred to an entry on 15 February 2017 which read:
“Past Trauma
Discussed past history of physical and sexual abuse
By mother [the current employer acknowledged that the evidence showed that it was a babysitter]
Was left repeatedly at refuges with brother, by mother
Had ? preservative allergies and was rushed to hospital several times as a child
Held down and forced to take medication
Was repressing this, but working +++
Last year episode with work/retrenchment opened up these issues
……”
31.	The appellant employer submitted that the medical evidence revealed the severity of Ms Harle’s psychiatric illness before she commenced employment with the Council in “mid-2016”.
32.	The evidence further showed, the appellant employer submitted, that Ms Harle continued to receive treatment for her pre-existing condition whilst she was working for the Council and before the onset of the subject injury in February 2018.
33.	We were referred to Vitaz v Westform NSW Pty Ltd, a case that is commonly cited as authority for the proposition that an asymptomatic condition can be the subject of a s 323 deduction.
34.	We were also referred to the application of cl 11.10 of the Guides as interpreted in Marks v Secretary, Department of Communities and Justice (No2). It submitted that cl 11.10 of the Guides had been found to be “contrary to the legislation.” 
35.	The appellant employer submitted that the MA “failed to properly consider the history of prior injury and treatment in the application of s 323”. The deduction of 1/10th it was argued was at odds with the available evidence and the deduction should have been greater. We were also referred to cl 1.28 of the Guides.
The respondent
36.	The respondent submitted that the assessment of the s 323 deduction was a matter of clinical judgement and referred to Marina Pitsonis v Registrar Workers Compensation Commission.
37.	Ms Harle submitted that the appellant employer sought to establish two propositions:
1.	that there was no difficulty with the extent of the deduction, and 
2.	that the 1/10th deduction was at odds with the available evidence. 
38.	Ms Harle submitted that the appellant employer did not develop its argument. There was no test that applied to the manner in which an MA calculated the extent of the deduction, it was submitted. The MA was expected to use his clinical judgment, and if the doctor says in good faith that the question was too difficult to determine then, it was submitted, “that must be the end of the question”.
39.	As to the deduction being at odds with the available evidence, Ms Harle submitted, uncontroversially, that the statutory deduction provided in s 323(2) applied only if the deduction was too costly or difficult to assess.
40.	The MA had in any event given a detailed review of the evidence, it was submitted. He had acknowledged the opinions of Dr Cross and Dr Mitchell (Ms Harle’s GP) that Ms Harle had suffered a significant aggravation of her pre-existing condition. 
41.	It was submitted that the evidentiary matters referred to by the appellant contained no argument as to identification of error. Ms Harle conceded that Dr Lee did suggest a one half deduction but Dr Lee’s opinion was misconceived because he was relying on “uncorroborated evidence and unreliable reporting” Ms Harle said, referring we assume to the finding by the MA.
42.	We were referred to Cole v Wenaline Pty Ltd and Ryder v Sundance Bakehouse as to the principles applicable in the application of s 323.
43.	Ms Harle noted the appellant employer’s submissions concerning whether cl 11.10 of the Guides were ultra vires the Act, but said that the relevance of the issue was unclear. It had not been argued that the MA erred in relying on the guideline.
DISCUSSION
Preliminary
Date of injury
44.	We note that this matter was referred to the MA with a date of injury of 22 August 2018. Prima facie this establishes that the worker alleged that she suffered a personal injury as defined by s 4(a), on that day. 
45.	Section 4 provides:
“4 Definition of ‘injury’
(cf former s 6 (1))
In this Act-
Injury-
(a)	means personal injury arising out of or in the course of employment,
(b)	includes a disease injury, which means-
(i)	a disease that is contracted by a worker in the course of employment but only if the employment was the main contributing factor to contracting the disease, and
(ii)	the aggravation, acceleration, exacerbation or deterioration in the course of employment of any disease, but only if the employment was the main contributing factor to the aggravation, acceleration, exacerbation or deterioration of the disease…
(c)	 …”
46.	It is apparent that from the way in which the MA approached this case, and from the submissions that have been made by both sides that there was an agreement that the matter was to be approached as if it was a disease case pursuant to s 4(b)(ii).
47.	That was certainly the opinion of the MA who, in a thorough and comprehensive survey of the evidence before him, found “the applicant’s work injury has caused an aggravation of her post traumatic stress disorder”.
48.	He also found that the workplace conditions had caused a Persistent Depressive Disorder with anxious distress.
49.	 The Panel is content to adopt the same approach and deal with the issues as if this were an injury as defined in s 4(b)(ii) with a deemed date of injury of 22 August 2018.
Section 323
50.	Section 323 of the 1998 Act provides relevantly:
“(1)	In assessing the degree of permanent impairment resulting from an injury, there is to be a deduction for any proportion of the impairment that is due to any previous injury (whether or not it is an injury for which compensation has been paid or is payable under Division 4 of Part 3 of the 1987 Act) or that is due to any pre-existing condition or abnormality.
(2) 	If the extent of a deduction under this section (or a part of it) will be difficult or costly to determine (because, for example, of the absence of medical evidence), it is to be assumed (for the purpose of avoiding disputation) that the deduction (or the relevant part of it) is 10% of the impairment, unless this assumption is at odds with the available evidence.”
51.	The appellant employer’s submissions in essence asserted that the reliance on s 323(2) to determine the extent of the impairment caused by the pre-existing condition was a demonstrable error. The appellant employer sought to establish that the extent of the deduction was not difficult or costly to assess, and that the one tenth finding was indeed at odds with the available evidence. 
52.	However, Ms Harle’s response was that whether the assessment of the deduction was too difficult or costly to assess was entirely a matter for the clinical judgment of the MA. Mr Stockley, who wrote the respondent’s submissions, said (to repeat):
“If the doctor says in good faith, ‘it’s too difficult for me to determine’, that must be the end of the question.”
53.	We reject that submission. An MA is bound to disclose his path of reasoning and, as stated in Vegan, to which we referred at the outset of these reasons, an MA is bound to explain his conclusion where more than one is open on the evidence. The MA acknowledged, at [18]-[20] above, the evidence that was before him pertaining to Ms Harles’ pre-existing condition. However, in discussing the other medical opinions and findings submitted by the parties at [10c] of his MAC, he did not refer to any of that evidence. 
54.	The MA referred to Ms Harle’s admission to Northside Macarthur and her psychotherapy with Ms Slawitchka when explaining his deduction at [10a], but only to emphasise that the work injury constituted a “significant aggravation” of that condition. He did not explain why he had assessed the 1/10th deduction. 
55.	Further, the MA’s assumption that the available evidence was not at odds with the evidence was factually incorrect. It is convenient to refer to that evidence at this point. 
PRE-EMPLOYMENT EVIDENCE
Statement Ms Harle 14 November 2018
56.	The MA noted that Ms Harle’s first mental health contact was “in 2016.” This in fact, Ms Harle said, occurred in May 2016, after she returned from the United States. She had been visiting as Senior Policy Advisor for Parramatta City Council, and had received notice that her employment would be terminated. She said in her statement of 14 November 2018 that she became ill when she was alone in America, which:
“..contributed to the situation that led to my condition of anxiety and depression..”
57.	Ms Harle said:
“I have been diagnosed with anxiety, depression and I think complex trauma.
I first suffered this condition in May 2016…” 
GP notes
58.	The clinical notes of the Schwarz Family Practice demonstrated that Ms Harle first attended on 18 May 2016, and was referred to a psychologist on 20 May 2016.
Statement Rina Day 7 November 2018
59.	The MA did not refer to a statement from Ms Rina Day of 7 November 2018. 
60.	Ms Day held the position of Team Leader Corporate Planning with the appellant employer at all material times. Ms Day confirmed that she had met Ms Harle when she was working for Camden Council in 2015, and she noted that Ms Harle left to work with Parramatta Council as the Mayor’s Policy Adviser.
61.	Ms Day said she maintained contact whilst Ms Harle was at Parramatta.
62.	Ms Day said:
“I phoned her on one occasion and she told me she was actually overseas with work and said she was not well and would phone me when she returns to Australia. She did this and told me that she was not well and had applied for a Senior Governance position at Camden Council. She also told me that she could not start at that time because she was not well and that Charles Webber gave her an extension on the starting date of one month. Carolyn was still not well enough to work, and she declined the offer of acceptance. In my conversations with Carolyn, she also told me that she was in Nowra in a mental health retreat or similar and might not be able to take my calls while staying at that facility. She also mentioned that she had thought about killing herself. Carolyn also spoke about wanting to separate from her husband. I spoke to her about these issues and the need to speak to her husband and work through the issues.
These conversations were in the first half of 2016. Carolyn and I subsequently met and had lunch at Narellan. During this lunch meeting, Carolyn was crying most of the time.
She was very unwell and I offered to make an appointment with my Allied Health
professional, Al Health, Padstow. She gave me consent and I made an appointment for Carolyn. Carolyn was very nervous about attending and so I offered to meet her after her first session.”
63.	Ms Day met Ms Harle following that session. She said:
“…..I met with Carolyn and had a cup of tea which I took from home, as
she told me about her health situation. She told me her mother was not well and was in an institution. She also spoke about her father and step-mother and brother. . I was aware Carolyn was seeing possibly two Psychologists and a General Practitioner at that time. They agreed Carolyn was fit to work on a casual basis and I floated the idea of Carolyn working in my team on a casual basis, as she had explained to me that she had experience in policy and corporate planning.”
64.	Ms Day said that as a result of her mental condition Ms Harle was not well enough to work full time and Ms Harle was retained on a casual basis three days a week from 19 September 2016. She said that Human Resources wanted to know the specific days that Ms Harle would be working when her employment contract was changed, which resulted in an increase of her hours at work from Monday 1 November 2016.
65.	Ms Day said that she tried to keep the working arrangement flexible “working around Carolyn’s condition and the need for medical appointments.”
Ms Day noted that Ms Harle had eventually became a full time permanent employee 
Dr Mark Cross
66.	The MA acknowledged that Ms Harle had been admitted to Northside Macarthur for ten weeks under Dr Cross. A report from Dr Mark Cross, the respondent’s treating psychiatrist, dated 8 September 2016 was amongst the clinical notes lodged. 
67.	Dr Cross recorded that the transition home (presumably from Northside Macarthur) was hard, but Ms Harle was then feeling “generally okay”. He noted that Ms Harle was still feeling upset in the mornings and had a mild tremor from the medication, which worsened if she got anxious. Dr Cross noted that her first session with Ms Slawitschka, Ms Harle’s treating psychologist, made her feel “triggered.’ She was then attending “Tuesday day group” and was to continue her psychology treatment. Dr Cross noted that Ms Harle was to apply for the job with the appellant employer.
68.	In a further report dated 13 December 2016, Dr Cross noted:
“I reviewed Carolyn today, work is generally going okay she is working 4 days a week, she finds this distracting. Sleep is an issue at present with increased nightmares and lack of deep sleep….. She was tearful during the interview about certain “memories” returning. We spent some time discussing strategies about dealing with childhood memories and emotions linked to them. She is finding sessions with Emma Slawitschka helpful."
69.	Dr Cross noted the current medication of Cymbalta 30 mg bd.
Emma Slawitschka
70.	Dr Cross’ report confirms that Ms Harle was seeing Ms Slawitschka at the time of his report, 8 September 2016. Ms Emma Slawitschka’s report of 25 October 2016 was also before the MA. Ms Slawitschka’s report confirmed that Ms Harle had been under the care of another Psychologist, Ms Katrina Marchant, and that Ms Harle had been under a mental health care plan. Ms Slawitschka was not precise about actual dates but it is clear that she was treating Ms Harle on 8 September 2016.
Failure to give adequate reasons
71.	This evidence was directly relevant to the application of s 323, and as indicated, the MA was obliged to give reasons as to why he did not consider it at odds with the statutory presumption of 1/10th and thus applied the terms of s 323(2). In particular the evidence of Ms Day, which stated that the appellant employer was aware that Ms Harle’s capacity to work full time was so compromised by her psychological disorder that she could only work a three-day week, was relevant. It was a matter that clearly indicated the presence of a pre-existing condition of some magnitude. His failure to adequately explain that evidence was a demonstrable error. 
Error of fact
72.	Moreover, in finding that the pre-existing condition contributed 1/10th impairment to that caused by the subject injury, the MA made a demonstrable error of fact. There was no absence of evidence, medical or otherwise, on which to assess the appropriate deduction, and there was no cost involved, as the evidence was before the MA. Thus the assumption upon which the statutory 1/10th deduction could be applied, had no factual basis.
 Wrong principle
73.	A further matter for comment relates to the reasons that the MA did give. His reasons for the extent of the deduction appeared to be based on some misapprehension as to the proper basis for the application of s 323. His observation that there was “significant evidence” on clinical examination and in the ‘collateral materials” to establish that the work injury had caused a “significant aggravation” of Ms Harle’s pre-existing condition, was nothing to the point. The work injury was admitted. The MA’s task, with respect, was to consider whether the pre-existing condition itself had caused an impairment which contributed to the WPI created by that aggravation, and if it had, the degree if such impairment. 
74.	In Ryder v Sundance Bakehouse Pty Ltd  Campbell J stated at [45]:
“45 	What s 323 requires is an inquiry into whether there are other causes, (previous injury, or pre-existing abnormality), of an impairment caused by a work injury. A proportion of the impairment would be due to the pre-existing abnormality (even if that proportion cannot be precisely identified without difficulty or expense) only if it can be said that the pre-existing abnormality made a difference to the outcome in terms of the degree of impairment resulting from the work injury. If there is no difference in outcome, that is to say, if the degree of impairment is not greater than it would otherwise have been as a result of the injury, it is impossible to say that a proportion of it is due to the pre-existing abnormality. To put it another way, the Panel must be satisfied that but for the pre-existing abnormality, the degree of impairment resulting from the work injury would not have been as great.”
75.	The function of the MA was therefore to enquire as to the degree of impairment the pre-existing condition contributed to that which resulted from the work injury, which in this case was the aggravation of Ms Harle’s pre-existing condition. Whether that aggravation had been significant or not was not germane to his function, and this apparent misperception was illustrated by his comments at [10c] which we reproduced above at [22] above in bullet form, wherein he gave a thorough exposition of all the evidence before him which confirmed the onset of the work injury. Whilst he discussed the assessments for the different categories and his reasons for differing from other opinions, he did not discuss the evidence that was before him regarding Ms Harle’s pre-existing condition. 
Misapprehension as to correct principle
76.	Similarly, the MA’s comment regarding the opinion of Dr Lee was also misconceived. In his report of 19 February 2021 Dr Lee considered Ms Harle’s diagnosis. He said:
“Noting that her difficulties in early childhood, her pre-existing anxiety and depression which required admission to Northside Clinic, the lack of verification of her allegations against Camden Council, the variability of her report from Dr Cross and the [overreporting] demonstrated on the MMPI, it is my opinion that she suffers from Borderline Personality Disorder….
…..
In my opinion, it is appropriate to deduct 50% on the basis of uncorroborated evidence, and evidence of unreliable reporting.”
77.	Uncorroborated evidence and unreliable reporting thus are matters that might inform a medical expert in evaluating the extent of an impairment caused by a pre-existing condition. The MA accordingly erred when he stated that that no allowance could be made in the Guides for such evidentiary lapses. 
Incorrect criteria
78.	The failure by the MA to explain why this body of evidence was ignored and indeed why the MA had recourse to the provisions of s 323(2) constituted both a demonstrable error in his failure to give adequate reasons, and the application of incorrect criteria in his reliance on s 323(2). There was no shortage of medical evidence before the MA regarding Ms Harle’s pre-existing condition, and that evidence was at odds with his conclusion that the statutory 1/10th deduction should be made. The correct criteria to be applied was that of s 323(1).
79.	It follows that the MAC must be revoked, and the Panel determine the appropriate deduction in the light of the evidence to which we have referred. This in turn has raised a further issue. 
The appropriate deduction
80.	The Guides have been promulgated pursuant to s 376 of the 1998 Act and their effect by virtue of s 322(1) is that the assessment of WPI “is to be made” in accordance with those Guides. Section 322(1) provides:
“322 ASSESSMENT OF IMPAIRMENT
(1) The assessment of the degree of permanent impairment of an injured worker for the purposes of the Workers Compensation Acts is to be made in accordance with Workers Compensation Guidelines (as in force at the time the assessment is made) issued for that purpose.”
81.	In Marks (No 2) Simpson AJ said from [7]
7.	“Section 323(1) requires that, in the assessment of the degree of permanent impairment, there is to be a deduction for any proportion of the impairment so assessed that is due to “any previous injury ... or ... any pre-existing condition or abnormality”. Subsection (4) provides that the Guidelines:
‘... may make provision for or with respect to the determination of the deduction required by this section’.”
8.	Although, with respect to physical injury, the Guidelines made under s 376 have adopted Guidelines issued by the American Medical Association (commonly referred to as “AMA5”), in respect of psychiatric injury a separate chapter of the Guidelines (Ch 11) has been issued. Guideline 11.10 provides:
‘To measure the impairment caused by a work-related injury or incident, the psychiatrist must measure the proportion of WPI [whole person impairment] due to a pre-existing condition. Pre-existing impairment is calculated using the same method for calculating current impairment levels. The assessing psychiatrist uses all available information to rate the injured worker’s pre-injury level of functioning in each of the areas of function. The percentage impairment is calculated using the aggregate score and median class score using the conversion table [set out] below. The injured worker’s current level of WPI % is then assessed, and the pre-existing WPI % is subtracted from their current level, to obtain the percentage of permanent impairment directly attributable to the work-related injury.’..” (emphasis added)
82.	Her Honour then noted the dilemma faced by the Appeal Panel in that case. She said at [9]:
“….It seems reasonably clear that the Appeal Panel considered that Guideline 11.10 was inconsistent with s 323(1) as interpreted in previous decisions of this Court. That was because Guideline 11.10 focused on “pre-injury level of functioning” and not on any contribution made to the current level of functioning by a pre-existing condition or abnormality (whether or not symptomatic). …” 
83.	At [24], her Honour said (with the authorities omitted):
“The proposition that a guideline inconsistent with statute could take precedence is contrary to authority ….”
84.	Her Honour said at [28]:
“The submission was maintained that s 322(1) “gives precedence” to the Guidelines. There is nothing in either s 376 or s 323(4) that authorises the issue of guidelines that are inconsistent with any provision of the WIM Act. It is implicit, even if not expressly stated, in any conferral of power to make regulations, guidelines, or any other kind of delegated legislation (if that is what guidelines are) that the exercise of the power be consistent with the provisions of the legislation under which the power is conferred. So much is explicit in s 323(4)….. Subsection (4) authorises the State Insurance Regulatory Authority to make provision “for or with respect to the determination of the deduction required by this section” (emphasis added). That leads inexorably back to subs (1), construed in accordance with established authority.”
85.	Her Honour then concluded by saying at [29]:
“I have therefore concluded that Guideline 11.10 of the Workers Compensation Guidelines is, to the extent that it excludes, in the application of s 323(1) of the WIM Act to any psychiatric or psychological impairment, consideration of any contribution made to the impairment by a pre-existing but asymptomatic condition, inconsistent with s 323(1) and invalid.”
86.	In the case before her, Simpson J was considering the application of cl 11.10 in the context of an asymptomatic pre-existing condition, and declared that the clause was ultra vires insofar as it purported to relate to such conditions. In the present case however, the case concerns a symptomatic previous injury, pre-existing condition or abnormality. 
87.	In the present case the MA had only referred to the provisions of s 323 in making his deduction, and we accordingly were faced with the dilemma as to whether to apply the provisions of cl 11.10 or s 323. We had not been addressed on these matters, and accordingly issued the following direction. 
Call for further submissions
88.	The Panel requires further assistance from the parties.
89.	The appellant employer made the following submission:
“(h) 	Further, in the context of psychological injury impairment assessments, the Supreme Court in the recent case of Marks v Secretary, Department of Communities and Justice (No 2) [2021] NSWSC 616 (Marks) determined that to the extent that clause 11.10 of the SIRA Guidelines for Evaluation of Permanent Impairment is inconsistent with section 323, section 323 prevails. It held that there is no distinction between the manner in which section 323 operates in respect of a physical or psychological injury, with there being nothing in section 323 that authorises exclusion of asymptomatic pre-existing conditions as being causative or partially causative of a subsequent permanent impairment. In other words, clause 11.10 of the Guidelines has been found to have been promulgated in terms which are contrary to the legislation.

(i) 	In Marks, the Appeal Panel found that if it were to apply clause 11.10 to its assessment, the deduction for the pre-existing condition would be nil because at the time of his workplace injury the claimant in that case showed no signs of his prior injury and his pre-injury level of functioning was normal. The Appeal Panel however determined that a pre-existing PTSD and intermittent depressive condition (albeit asymptomatic at the time of the workplace injury in that case) rendered the claimant (Mr Marks) more vulnerable to psychiatric injury and therefore contributed to his permanent impairment. The panel therefore applied a deduction in accordance with section 323, a decision that was upheld by the Supreme Court.”
90.	Mr Paul Stockley, who provided the submissions on behalf of Ms Harle, responded in the following terms:
“14. 	The Appellant took care to point out that reliance upon the SIRA Guideline 11.10 was not permissible because it had been held to be ultra vires the Act in the decision of Marks v Department of Communities and Justice (No 2) (submissions paras 3(h) and (k). The relevance of this part of the submission is not clear, as it is not argued that the Medical Assessor erred in placing reliance upon the Guideline.”
91.	The Medical Appeal Panel (Panel) notes that the submissions by the appellant employer accurately reflect the findings made by Simpson AJ in Marks. We are concerned however that the relevance of those findings has not been clearly explained in the circumstances of this case. 
92.	The issue considered by Her Honour concerned, as noted, the validity of cl 11.10 of the NSW Workers Compensation Guidelines for the Evaluation of Permanent Impairment, 4th ed, reissued 1 March 2021 (the Guides). Simpson AJ in two judgments, Marks v Secretary, Department of Communities and Justice and Marks v Secretary Department of Communities and Justice (No 2), concluded that cl 11.10, insofar as it purported to relate to the assessment of asymptomatic pre-existing psychological conditions, was ultra vires the empowering legislation.
93.	In her first judgment, Her Honour considered an earlier case which discussed the same issue, which was twice before the Supreme Court, Broadspectrum (Australia) Ltd v Wills. She said at [56]:
“Buried in [the] submissions, and not addressed by either party, is what I consider to be an important underlying issue, and possibly the key to the approach taken by the Appeal Panel. One way of understanding the reasoning of the Appeal Panel, it seems to me, is that it took the course it did (in both Wills and in the present case) because it considered that Guideline 11.10 is inconsistent with s 323(1). That could, at least potentially, raise an issue as to the validity of Guideline 11.10. Two questions arise:
(i)	is there a relevant inconsistency?;
(ii) 	if so, what is the effect of that inconsistency? Specifically, under which provision is the assessment to be made?”
94.	Her Honour found from [57] that the statutory provision must prevail, citing Henderson v QBE Insurance (Australia) Ltd, but directed that the parties provide further submissions as to the further issues which she expressed at [65]:
“… I propose to give the parties the opportunity to make submissions as to:
(i) 	whether Guideline 11.10 of the Workers Compensation Guidelines is inconsistent with s 323(1) of the WIM Act; and
(ii) 	if so,
(a)	the consequence of that inconsistency and,
(b) 	specifically, whether Guideline 11.10 is beyond power.”
95.	In Marks (No 2) Simpson AJ found at [29]:
“I have therefore concluded that Guideline 11.10 of the Workers Compensation Guidelines is, to the extent that it excludes, in the application of s 323(1) of the WIM Act to any psychiatric or psychological impairment, consideration of any contribution made to the impairment by a pre-existing but asymptomatic condition, inconsistent with s 323(1) and invalid.”
96.	The facts in both Wills and Marks concerned workers who, when they commenced employment with their respective employers, were asymptomatic, although each had pre-existing conditions that contributed to the impairment caused by the subject injury. 
97.	The facts in the present case are different, as they concern a pre-existing symptomatic condition, but the question remains the same: is the methodology mandated by the guideline within power? The following matters are of interest, although not intended to be a comprehensive survey of the issues:
•	Section 323 is concerned with the assessment of impairment caused by a pre-existing condition, as the worker presents to the MA on the day of assessment, pursuant to cl 1.6a of the Guides. Clause 11.10 requires the MA to make an estimate as to the worker’s condition as he/she would have presented at a time just prior to the occurrence of the injury. The latter method, by definition, requires the MA to make an educated guess, as the guideline provides that he/she is to use the “all available information” to construct a rating scale. This might be inconsistent with the statute, as the deduction is assessed in accordance with the Guides and overlooks the requirement that s 323 must be read as a whole in its legislative context. See Ryder v Sundance Bakehouse at [41]-[42] per Campbell J.
•	Whilst both methods are concerned with the assessment of a deductible impairment, s 323 requires a consideration of “any previous injury (whether or not it is an injury for which compensation has been paid or is payable under Division 4 of Part 3 of the 1987 Act), or any pre-existing condition or abnormality”, whilst cl 11.10 restricts the MA to a consideration to “a pre-existing condition” only. Thus, accepting for the sake of argument, without so finding, that whilst working for Parramatta Council in the United States Ms Harle suffered a psychological injury, it would appear that the clause might be inconsistent with the legislation, as her condition was not a pre-existing condition, but a previous injury. 
•	Similarly, there appears to be no legislative authority that informs the basis of a finding that the percentage of pre-existing impairment requirement “cannot be assessed” where the deduction is presumed to be 1/10th of the assessed impairment. There is no requirement that such an assessment be based within the limitations described by s 323(2). The assessment could be quite random, and made where there was no difficulty or cost or a need to avoid disputation, where, for example, there was no absence of evidence. An assessment therefore might be made that was at odds with the available evidence. This difficulty is present in cases of symptomatic workers as well as asymptomatic workers, the latter to whom the guideline no longer applies. The MA in the present case has made a 1/10th deduction but, again accepting for the sake of argument without so finding, there was no shortage of medical evidence, no cost difficulty, and that the assessment was at odds with the available evidence, the guideline again might be inconsistent with the empowering legislation, specifically s 323(2).
•	We note that the MA has cited s 323(2) as the justification for his assessment of 1/10th, but that in turn raises the question as to whether he might have applied the wrong test by not applying the provisions of the guideline. The same question arises in his failure to construct a psychiatric impairment rating scale based on Ms Harle’s condition when she suffered her injury. In that regard we note that the date has been approached by the MA and the parties on the basis that the referred date is a deemed date and the relevant date for the purposes of a s 323 assessment would be the date the worker commenced employment.
98.	The submissions should address:
(i) 	whether Guideline 11.10 of the Workers Compensation Guidelines is inconsistent with s 323(1) of the WIM Act in these circumstances; and
(ii)	 if so,
(a)	the consequence of that inconsistency and,
(b)	specifically, whether Guideline 11.10 is beyond power in these circumstances.
99.	We accordingly direct the parties to each provide written submissions by 1 July 2022, and any response thereto by 14 July 2022.” 
100.	The written submissions were duly filed.
The appellant employer
101.	The appellant employer submitted that where the provisions of s 323(2) were invoked, it was necessary to enquire whether the available evidence was at odds with the statutory deduction. We were referred to the dissenting judgment of Giles J in SAS Trustee Corporation v Pearce in that regard, and we accept that as a matter of statutory interpretation such an enquiry would follow.
102.	We also accept the submission that a s 323 assessment cannot be permitted on the basis of assumption or hypothesis, as was stated in Cole v Wenaline Pty Ltd and affirmed constantly since. 
103.	Accordingly, the appellant employer submitted that in the application of s 323 an MA was required to have regard to the evidence, the only place for assumption being the statutory assumption provided in s 323(2).
104.	The appellant employer then reproduced the terms of cl 11.10 of the Guides, and submitted that its terms were inconsistent with s 323, referring by way of footnote to Marks (no 2).
105.	Firstly, it submitted that the methodology involved in the application s 323 did not require the construction of a rateable percentage impairment, to be deducted from the overall impairment, based on a claimant’s psychiatric state when he/she commenced employment or just prior to the subject injury.
106.	Section 323 required a deduction to be assessed for any proportion of impairment caused by the previous injury, pre-existing condition or abnormality. The construction of a pre-injury impairment scale was not a true reflection of how the previous injury, pre-existing condition or abnormality affected the overall WPI. 
107.	Secondly, it was submitted that the accepted manner of the application of s 323 required a conclusion, based on the evidence, that the actual previous injury, pre-existing condition or abnormality caused or contributed to the impairment assessed as a result of the subject injury. We were referred to dicta from Schmidt J in Cole to that effect.
108.	Thirdly, the application of cl 11.10 was limited to cases where there was a “pre-existing condition” only. The cause of Ms Harle’s pre-existing state, the appellant employer argued, was in the context of an injury that had been suffered whilst she had been employed by Parramatta Council. The evidence showed that there was no dispute that at the time Ms Harle commenced with the respondent she was symptomatic with anxiety, depression and general psychological distress. On this evidence the cause was a previous injury with Parramatta Council, and the appellant employer argued that therefore the terms of cl 11.10 could not apply, as the terms “previous injury” and “abnormality” were not included. Clause 11.10 was only applicable to a “pre-existing condition.”
109.	Fourthly, the appellant employer also submitted that there was no provision in the guideline for a consideration of whether the “pre-injury level of functioning” was itself affected by a pre-existing condition which, while symptomatic, nonetheless permitted a worker to obtain employment, as indeed was the case in Ms Harle’s case.
110.	Fifthly, there was a further inconsistency, it was argued, with regard to the 1/10th deduction. The appellant employer submitted (successfully as we have found) that s 323(2) did not apply because, amongst other things, as there was a wealth of material to demonstrate that the statutory assumption was at odds with the available evidence.
111.	The terms of the 10% deduction assumption in cl 11.10 were not restricted to the criteria mandated by s 323(2), it was submitted. The appellant employer said:
“29. 	It follows that clause 11.10 goes beyond the power given to it by section 376 to the extent it provides a methodology for calculating the extent of a deduction which is inconsistent with the correct application of section 323.” 
Mr Stockley
112.	Mr Stockley submitted that guideline 11.10 had been considered ultra vires in Marks. He argued that it was either ultra vires or it was not, and it could not be both, as we understood him.
113.	We were bound by Marks, Mr Stockley said, and the consequence of cl 11.10 being inconsistent was that the MA had not erred in failing to apply the guideline.
114.	The guideline, Mr Stockley argued, was not relevant. The employer had not raised it as an appellable error. The complaint was that the MA had fallen into error by applying the terms of s323(2).
Discernment
115.	It can be seen that, with respect, the ratio decidendi of Marks (No 2) is not as was assumed by the respondent. In our call for submissions, we cited Simpson AJ’s conclusion that cl 11.10 was inconsistent with s 323(1) and invalid to the extent that it excluded consideration of any contribution made to the impairment by a pre-existing but asymptomatic condition. The decision in Marks (No 2) did not hold that cl 11.10 was ultra vires in toto. The question raised by this case was whether the guideline is valid where it involves a consideration of the impairment caused by a pre-existing condition that was symptomatic.
116.	As discussed by Simpson AJ, cl 11.10 focusses on the “pre-injury level of functioning” and not on the contribution made to the current level of functioning by a pre-existing condition. There is well established authority regarding the application of s 323 which is concerned with the manner in which the level of functioning is to be established. We have already referred to Campbell J.’s decision in Ryder in that regard.
117.	In Cole v Wenaline Pty Ltd Schmidt J said:
“38.	What s 323 required, however, was that the evidence be considered, so that it could be determined, firstly, what the level of impairment after the second injury was. Secondly, whether a proportion of that impairment was due to the first injury. Thirdly, what that proportion was. Undoubtedly in undertaking this exercise, the medical members of an Appeal Panel must utilise their medical judgement, knowledge and experience. Nevertheless, all stages of the statutory exercise must be undertaken in the light of the evidence and without the making of assumptions not provided for by the section.”
118.	In Elcheikh v Diamond Formwork (NSW) Pty Ltd Schmidt J referred to her decision in Cole, stating:
“88.	Section 323 requires that once the level of impairment which results from a work injury has been established, that a medical specialist must make 'a deduction for any proportion of the impairment that is due to any previous injury'. As discussed in Cole v Wenaline Pty Limited at [29] that requires a conclusion:
‘on the evidence, that the pre-existing injury, pre-existing condition or abnormality caused or contributed to that impairment'.
89.	As discussed in Cole v Wenaline Pty Limited at [30], that assessment cannot be made on the basis of an assumption or hypothesis that a pre-existing condition contributed to the impairment flowing from the subsequent injury. It has to have regard to the evidence as to the actual consequences of the pre-existing condition.”
119.	It is thus apparent that the methodology by which s 323 is to be applied is one that requires a focus on the evidence pertaining to the actual pre-existing condition, and it is in this respect that cl 11.10 is inconsistent with s 323. Whilst the clause is correct to state that the pre-existing condition is to be “measured”, it is inconsistent with s 323 to provide that the calculation be related to the pre-injury level of functioning. 
120.	The above authorities establish that the focus of the calculation be on the pre-existing condition itself, and the evidence relating to its actual consequences. That evidence is provided with the referral to the MA by the President’s delegate, and it is concerned with the assessment of the WPI caused by the subject injury. There is no requirement to provide evidence as to a claimant’s pre-injury functioning and such can only be inferred from the evidence regarding the subject injury. 
121.	This creates a difficulty in applying the terms of the clause, as the PIRS requires six specific areas of the behavioural consequences of the disorder to be assessed, and each category is itself divided into five classes of impairment. The first problem where a claimant is symptomatic at the time he/she commences employment, is that the MA has to construct two PIRS. He is required to assess a PIRS based on the claimant’s condition as he/she presents for assessment of the WPI caused by the subject injury. Clause 1.6 of the Guides provides:
“PART 2 – PRINCIPLES OF ASSESSMENT
1.6 The following is a basic summary of some key principles of permanent impairment assessments:
a. Assessing permanent impairment involves clinical assessment of the claimant as they present on the day
of assessment taking account the claimant’s relevant medical history and all available relevant medical information to determine:
•• whether the condition has reached Maximum Medical Improvement (MMI)
•• whether the claimant’s compensable injury/condition has resulted in an impairment
•• whether the resultant impairment is permanent
•• the degree of permanent impairment that results from the injury
•• the proportion of permanent impairment due to any previous injury, pre-existing condition or abnormality,
if any, in accordance with diagnostic and other objective criteria as outlined in these Guidelines.”
122.	The requirement in cl 11.10 for an MA to also construct a PIRS at an earlier point in time creates some conceptual difficulty. If the claimant were symptomatic at the commencement of employment, and had suffered further symptoms as a result of the subject injury, an MA could necessarily have to use assumption or hypothesis to establish which class of impairment in each category to apply in constructing that earlier PIRS.
123.	In Ryder, Campbell J considered the legislative and authoritative history of s 323. He said at [42]:
“In the present context the critical question is the causation question which, expressed by adapting the terms of the statute is whether a portion of the 15 per cent whole person impairment Ms Ryder suffered as a result of her work injury was due to a pre-existing condition or abnormality i.e. degenerative disc disease. The argument advanced on behalf of Ms Ryder is effectively that the proportion must be capable of assessment in accordance with the WorkCover Guides for s 323(1) to be satisfied. With respect this overlooks the requirement that the section must be read as a whole and in its legislative context. …
43.	I acknowledge that the express words of s 323(1) require that some definite part, even if it is difficult or costly to assess in precise terms, of the impairment has been caused by, in this case, a pre-existing condition. But the interpretation adopted by the Court of Appeal is that the section is engaged if the pre-existing condition, or previous injury where applicable, is a concurrent necessary condition, with the work injury, of the degree of permanent impairment.”
124.	Clause 11.10 is inconsistent with this principle. It does not allow a consideration of the effect of a particular pre-existing condition concurrent with the work injury, let alone a consideration of the degree of permanent impairment that pre-existing condition would have contributed to the work injury WPI.
125.	We accept therefore the appellant employer’s submission that the resultant PIRS calculation would not in any event be a true reflection of how the pre-existing condition affected the WPI caused by the subject injury. 
126.	We also accept the appellant employer’s submission that there is a further inconsistency contained within cl 11.10, as it purports to restrict its application only to cases of “pre-existing condition.” It can be noted that the terms of s 323 require a deduction in cases of “previous injury, pre-existing condition or abnormality.” Indeed, in the above citation from Ryder, Campbell J was careful to make the distinction. There is no legislative authority for such a restriction of the terms of cl 11.10 and it is a further example of an inconsistency with the terms of s 323.
127.	The next issue for consideration is whether the MA erred in any event by applying the terms of s 323 when the Guides provided that the appropriate deduction should be calculated pursuant to cl 11.10. We do not accept Mr Stockley’s submission that, because the terms of cl 11.10 were inconsistent, the MA had not erred by failing to apply the guideline. The MA was bound by s 322(1) when he made his assessment and, as we have outlined, Marks (No 2) did not affect the facts in this case, as Ms Harle was symptomatic when she commenced employment. Section 322(1) required that the assessment “is to be made” in accordance with the guideline, which remained in force concerning symptomatic pre-existing conditions. 
128.	Accordingly, the MA has applied incorrect criteria in any event. He was obliged to construct a PIRS assessment based on her condition when she commenced employment. We note in passing that, having accepted that the parties’ intention was that the date of injury, 22 August 2018, was to be a deemed date, the relevant date for the construction of the first PIRS would have been the date Ms Harle commenced employment, 19 September 2016. 
129.	We are accordingly satisfied that the whole of cl 11.10 of the Guides is inconsistent with s 323 of the 1998 Act and invalid.
The PIRS required by cl 11.10
130.	Before re-assessing the extent of the contribution by her previous injury to the permanent impairment caused by Ms Harle's subject work injury, pursuant to s 323, in case we are in error, the Panel has constructed a psychiatric impairment rating scale in accordance with cl 11.10. 
131.	We do not consider that “all the available materials” were adequate, and have relied on assumption to assess each category.
PERSONAL INJURY COMMISSION
Table 11.8: PIRS Rating Form as at the commencement of employment
Name	Carolyn Harle	Claim reference number (if known)	Not known	
DOB	22 August 1975	Age at time of injury	Forty six years old	
Date of Injury	22 August 2018	Occupation at time of injury	Corporate reporting and planning officer	
Date of Assessment	5 November 2021	Marital Status before injury	De facto	

Psychiatric diagnoses	1. Persistent Depressive Disorder with anxious distress	
	2. Posttraumatic Stress Disorder (aggravation)	
Psychiatric treatment	Mental health care monitoring: Dr Renae Mitchell Psychiatric supervision: Dr Mark Cross Psychotherapy: Vicki Schuldt
Current medications: Temazepam 10 mg po nocte prn	
Is impairment permanent?	Yes	

PIRS Category	Class	Reason for Decision	

 Self-care and personal hygiene

	2	 The worker was able to attend work on a part time basis and we assume therefore that she was able to live independently, although there is no direct evidence on that subject. There is not enough information about her dietary habits nor her daily routine. This assessment is largely based on assumption 
 	
Social and recreational activities	 2	 There is no information as to whether Ms Harle participated in social activities that were appropriate to her age, sex and culture, which is the definition for a person with a class 1, normal, value.
This estimate is again made on the assumption that because she was able to attend work on a part time basis she could at least occasionally go out to such activities.	
Travel	2	Ms Harle had been able to travel freely, as her statement of 14 November 2018 demonstrated. She first became ill in San Fransisco, it would seem. Whether she could still travel when she was employed by the appellant employer is again an inference we draw from the fact the she obtained this employment.	
Social functioning	2	There is some conflict as evidenced by the psychologists report, but generally, a mild impairment.	
Concentration, persistence and pace	2	The nature of Ms Harle’s job, and the desire evidenced by Ms Day to obtain her services of being to work only as a casual part time employee would indicate a mild impairment.	
Employability	3	Able to start work with respondent as a casual part time employee and work until 30 September 2018	
Score								Median Class	
 2	 2	 2	 	2	 	2	 	3		 2	
Aggregate Score Impairment						Total		%	
 					 	 	13	 7% 	
132.	Clause 11.10 then requires that amount to be deducted from the WPI assessed for the subject injury, which Ms Harle’s case would result in her entitlement being reduced by 41%. We do not consider that an appropriate deduction when the whole of the evidence is considered. This result also illustrates another difficulty with cl 11.10, the methodology of which is too arbitrary to fairly establish an appropriate calculation of the impairment caused by the pre-existing condition (or previous injury or abnormality).
133.	The evidence demonstrates that Ms Harle was in fact given an increase in her hours from 1 November 2016, and became a permanent employee in 2017. The totality of the evidence demonstrates that the MA had available the most compelling evidence of a pre-existing condition that was symptomatic at the time of the commencement of the worker’s employment with the appellant employer. However, it did not prevent her from gaining employment, albeit initially on a part time basis, nor did it prevent her from increasing those hours until in 2018 she decompensated after being bullied by the appellant employer’s staff Without that injury Ms Harle may well have continued her career. In all the circumstances we think a 20% deduction is appropriate.
134.	The appeal is accordingly allowed, and the MAC revoked. There being no challenge to the assessment of 19% found by the MA for the subject injury, a fresh certificate will issue for 15%, which reflects a deduction of 3.8% rounded to 4% in respect of our finding. 
135.	For these reasons, the Appeal Panel has determined that the MAC issued on 22 November 2021 should be revoked, and a new MAC should be issued. The new certificate is attached to this statement of reasons.

PERSONAL INJURY COMMISSION 

APPEAL PANEL
MEDICAL ASSESSMENT CERTIFICATE

Injuries received after 1 January 2002

Matter Number:	W3161/21 	
Applicant:	Camden Council 	
Respondent:	Carolyn Harle	

This Certificate is issued pursuant to s 328(5) of the Workplace Injury Management and Workers Compensation Act 1998.

The Appeal Panel revokes the Medical Assessment Certificate of Dr Christopher Bench and issues this new Medical Assessment Certificate as to the matters set out in the Table below:

Table - Whole Person Impairment (WPI) 
Body Part or system	Date of Injury	Clause, page and paragraph number in NSW workers compensation guidelines 	Clause, page, paragraph, figure and table numbers in AMA 5 Guides
	% WPI 	Proportion of permanent impairment due to pre-existing injury, abnormality or condition	Sub-total/s % WPI (after any deductions in column 6)	
Psychological/ psychiatric	22 August 2018 (deemed) -see our determination regarding the date of injury	Chapter 11	N/A	19%	20%	15%	

Total % WPI (the Combined Table values of all sub-totals) 
	15%