ZAMORA -v- OCS SERVICES PTY LTD [2025] WASCA 117 (4 August 2025)

1. At about 11 pm on 14 December 2021, while working as a cleaner at Westfield Whitford City Shopping Centre, the appellant had a slip‑and‑fall accident in a toilet cubicle. The fact of the fall was not in issue; but its extent and severity were disputed in the workers' compensation proceedings. In those circumstances the appellant's evidence as to the fall is best addressed in the context of the arbitrator's decision.
2. Shortly after the fall a photograph was taken showing the appellant lying on his back between the toilet bowl and the cubicle wall. An ambulance service was called at 11.31 pm. After midnight the appellant was taken by ambulance to Joondalup Health Campus. The appellant was admitted to the hospital as a patient and was discharged on 17 December 2021.
3. The appellant was subsequently reviewed and treated by numerous medical practitioners and a clinical psychologist. The practitioners prepared reports for the workers' compensation proceedings. Those reports, as well as the ambulance paramedics' reports and medical records of the Joondalup Health Campus, were before the arbitrator in the workers' compensation proceedings.

1. In her written decision the arbitrator first dealt with an objection ruling she made at the commencement of the arbitration hearing. It will be necessary to return to this when dealing with ground 1 in the appeal. In summary, counsel for the appellant objected to the respondent pursuing a submission to the effect that a 'significant issue' which needed to be determined was the appellant's 'credibility' in terms of the accident ‑ the respondent raising whether the accident caused the injuries asserted and the alleged incapacity. The arbitrator noted in her ruling that the severity of the fall as asserted by the appellant had clearly been in contest and should not take the appellant by surprise; the respondent was disputing that there was an injury and contending that there was no adequate medical evidence to prove an injury [11].
2. After identifying the issues that required a determination, the arbitrator referred to various general legal principles [13] - [18]. There is no suggestion that the arbitrator misstated any of the applicable legal principles. Relevantly, so far as ground 3 is concerned, the arbitrator identified that the standard of proof was the balance of probabilities and it was not necessary for there to be an exactness of proof to find that a fact was proven [15] ‑ [16]. Importantly, so far as the arbitrator was required to consider the appellant's reliability and credibility, the arbitrator stated:

My findings in regard to the slip and fall turn on my assessment of the reliability and credibility of the [appellant]. He was the only witness to the slip and fall and all of the medical opinions regarding his injuries and the development of any condition following the slip and fall rely on his self-reporting of the incident and subsequent symptoms. In order for me to accept the medical evidence, I must find that the information provided by [the appellant] to the doctors is reliable. The assessment of the credibility or reliability of evidence is a multi‑factorial task. The appearance and demeanour of witnesses are relevant factors, but there is a danger in too readily drawing conclusions about truthfulness and reliability solely or mainly from such considerations [18].

1. The arbitrator then referred herself to Fox v Percy[4] and in particular to the plurality's observation in favour of reasoning to a conclusion, as far as possible, on the basis of 'contemporary materials, objectively established facts and the apparent logic of events': Fox v Percy [31].
2. The arbitrator asked the question whether the appellant slipped and fell as asserted on 14 December 2021. The arbitrator started her consideration of that question by repeating the appellant's evidence. The appellant said that as he opened the door to leave the toilet cubicle his left foot slipped and he fell backwards. The appellant said that he landed on the toilet seat and he hit his head and fell to the side of the cubicle and landed on his right arm. The arbitrator referred to the appellant's evidence of what he was doing prior to deciding to use the toilet and compared that to different accounts that the appellant had given to three of the medical practitioners who treated or examined the appellant after the fall (Dr Tan, Dr Menon and Dr Cheng). The arbitrator then referred to different accounts that the appellant had given of what caused the fall ‑ here mentioning what was attributed to the appellant in admission notes and statements given to Dr Gupta and Dr Silbert as well as the appellant's evidence in cross-examination [19] - [32].
3. Under the heading 'the extent of the slip and fall', the arbitrator compared the appellant's evidence as to what happened in the fall with what the appellant stated in his dealings with the ambulance officers, hospital admission personnel and medical practitioners. Relevantly, a number of those records attributed statements to the appellant to the effect that he hit his lower back against the toilet [33] - [46].
4. The arbitrator observed that the photograph taken after the fall depicted some substance on the floor to the left of the toilet bowl [47]. The arbitrator then proceeded to state her conclusion as to the slip‑and‑fall and the appellant's reliability. As these findings are critical to grounds 1 and 2 of the appeal they should be reproduced in full:

I find that as [the appellant] stood up after using the toilet his left foot slipped forwards and he landed on the toilet seat. I further find that [the appellant] did not contact the toilet bowl with his back when he landed on the toilet seat. Nor was he thrown or bounced from the toilet seat as to land on the cubicle floor with any force as to cause injury to his back, right arm, or shoulder.

My reasons for finding this are based on my assessment of [the appellant]. I find [the appellant] is an unreliable witness and my finding as to this is also informed by the following matters.

(a) In his statement [the appellant] makes no reference to striking his back on the toilet seat. [The appellant] states 'I landed on the toilet seat and hit my head and fell to the side of the cubicle. I landed on my right arm'.

(b) [The appellant] gave conflicting accounts to the doctors as to what he was doing prior to the slip and fall. He variously reports that he was 'mopping the floor', 'cleaning a toilet', 'spot cleaning the escalator', and 'going down the escalator'.

(c) [The appellant's] evidence was that he did not clean toilets. [The appellant] told Dr Menon on 28 November 2022 that 'He was working as a cleaner and cleaning a toilet when he slipped and landed on his right hand side'.

(d) [The appellant] reported he 'slipped on water', 'slippery object', 'something slippery' and 'something soapy.'

(e) [The appellant] has variously reported that he 'slipped and fell', 'was thrown to the side of the toilet' and 'bouncing and thrown to the right side'.

(f) [The appellant] has variously reported he 'landed on his arm', 'landed on his shoulder on the floor tiles', 'struck his back on the floor', 'struck his back on the toilet seat', 'hit his shoulder on the toilet partition', 'hit the back of his head' and 'hit the right side of his head'.

(g) [The appellant's] reliability is further impacted as he did not disclose his prior history of anxiety and depression to either Ms Byers, clinical psychologist, or Dr Cheng, consultant psychiatrist.

(h) [The appellant] denied taking any medication prior to and at the time of the accident. When pressed [the appellant] did admit to taking Zopiclone, a sleeping medication but denied taking Citalopram despite Dr Gupta writing a script for Citalopram on 8 November 2021.

(i) [The appellant] became quite argumentative and angry under cross‑examination. [The appellant] deflected questions under cross‑examination by accusing counsel for [the respondent] of lying.

(j) And further, I find it inconceivable that Dr Bala, neurosurgeon, would sit and laugh in [the appellant's] face during a consultation as he stated in cross-examination [48] - [49]. (original emphasis)

1. Later in her reasons the arbitrator explained that she had found that the appellant was not a reliable witness based on the inconsistent histories given by the appellant to the various specialists [90].
2. The arbitrator moved to whether the appellant had suffered a personal injury by accident as a result of the slip‑and‑fall. Initially the arbitrator stated that it was not self‑evident that because the appellant slipped and fell he suffered a personal injury by accident [50]. After noting that the appellant claimed to have suffered soft tissue injuries to his lower back and right shoulder when he tripped and fell, the arbitrator reviewed the ambulance officer records, the hospital records (including radiological reports) and the subsequent radiological investigations and medical reports in evidence [54] - [63]. Having done so the arbitrator concluded:

There is no objective evidence that [the appellant] suffered an injury to his back and shoulder. There was no bleeding, lacerations, or bruising identified by the paramedics who attended from St John Ambulance nor by the medical staff at Joondalup Health Campus. The radiological investigations do not show any injury to [the appellant's] lower back, right shoulder, neck, or right arm [64].

1. There was evidence from Dr Silbert of a diagnosis of 'acute mechanical trauma' to the lumbosacral spine and the right shoulder and arm. There was also evidence from Dr Tan of a 'soft tissue injury' or a 'soft tissue contusion injury'. The arbitrator was not persuaded that Dr Silbert was able to identify any injury to enable him to make a reliable diagnosis [65]. The arbitrator went on to hold:

Both Dr Silbert and Dr Tan confirmed there was no objective evidence of any physical injuries as a result of the fall on 14 December 2021. I find the terms 'mechanical trauma' and 'soft tissue injury' are umbrella terms used to describe the subjective presentation of symptoms where a more specific diagnosis cannot be afforded and are so non‑specific in this case as to be of little use in identifying the injury.

As a lay person I am not certain what physiological change is encompassed by the broad terms 'soft tissue injury' or 'mechanical trauma'. Just as arbitrators should not generalise when specific diagnoses are available ... so too should the evidence provide for a specific identification of the injury alleged rather than a general description.

I find that [the appellant] has not established that that [sic] he suffered a 'soft tissue injury' or any 'mechanical trauma' to right shoulder/arm or lumbar spine on 14 December 2021 [67] - [69]. (original emphasis)

1. These findings are relevant to grounds 3 and 4 of the appeal to this court.
2. Later in her reasons the arbitrator reiterated that she had found that the appellant did not suffer a 'soft tissue injury' as a result of the slip‑and‑fall [88], [90].
3. The arbitrator went on to examine the appellant's case that he developed a chronic pain condition following a soft tissue injury. This aspect of the arbitrator's reasons attracted little attention in the appeal to this court. Accordingly, this part of the arbitrator's reasons need not be developed. In summary the arbitrator examined the available medical, psychological and psychiatric evidence [74] - [87]. The arbitrator found that the appellant had not established that he suffered from a neural sensitivity pain syndrome, a somatic symptoms disorder or depression. All of the opinions to the contrary were reliant on there being a 'soft tissue injury' or 'mechanical trauma' following the slip‑and‑fall. However, the arbitrator had found that the appellant did not suffer any such injuries following the slip‑and‑fall on 14 December 2021 [88].
4. Further reasons were given rejecting any medical opinion that the appellant suffered from neural sensitivity pain syndrome, a somatic symptom disorder and depression as a result of the slip‑and‑fall on 14 December 2021 [89] - [90].
5. For the reasons as stated, the arbitrator found that the appellant had not suffered a compensable injury [92]. The arbitrator concluded that she was unable to find that the slip‑and‑fall resulted in any injury to the appellant's right shoulder and lower back. There was, in the arbitrator's view, insufficient evidence to establish that the appellant suffered any injury to his lower back and right shoulder or any 'soft tissue injury'. Any incapacity to work had not resulted from any injury the appellant allegedly sustained on 14 December 2021 [6] - [7].
6. The arbitrator summarised her conclusions as follows:

The slip and fall that [the appellant] asserts on 14 December 2021 was not witnessed by anyone other than [the appellant]. The circumstances of the slip and fall and the self-reporting of his pain and psychological symptoms depends on the veracity of [the appellant's] evidence. All the specialists and treating doctors have been informed of these matters by [the appellant] and to a considerable extent have uncritically accepted that information and relied upon it when forming their opinions.

I find that [the appellant] is not a reliable witness. I find that [the appellant] did not provide accurate details of the slip and fall including the force of the fall nor did he disclose his prior history of psychological issue[s] to the treating doctors and medico legal specialists.

I find [the appellant] did not suffer a soft tissue injury or any compensable injury as a result of the slip and fall on 14 December [2021]. It follows that [the appellant] has not proved any compensable injury [93] - [95]. (emphasis added)

1. The present appeal is primarily directed to alleged legal errors in the arbitrator's decision‑making. To the extent that the appeal alleges error on the part of the primary judge, it is error in not recognising the alleged legal error by the arbitrator. The correctness standard applies to whether the arbitrator's decision‑making reveals legal error. It is, in the circumstances, only necessary to give a brief account of the primary judge's decision. It should, however, be said that the primary judge's reasons provide a detailed exposition of the facts and the legal issues together with the primary judge's conclusions. What follows in describing the primary reasons does a disservice to the careful and comprehensive reasons given by the primary judge.
2. There were two grounds of appeal in the appellant's appeal to the District Court. Shorn of particulars, they were:
   1. The arbitrator erred in mixed fact and law in finding (at [48] and [49]) that the appellant did not contact the toilet bowl with his back or land with any force as to cause injury to his back, right arm or shoulder, by denying the appellant procedural fairness and failing to provide adequate reasons.
   2. The arbitrator erred in mixed fact and law in finding (at [69]) that the appellant had not established that he suffered a 'soft tissue injury' or any 'mechanical trauma' to his right shoulder or arm or lumbar spine, by requiring an unnecessarily high level of satisfaction and exactness of proof and failing to give adequate reasons.
3. Ground 1 rolled up two distinct challenges to the arbitrator's factual findings at arbitrator's reasons [48] - [49] (those findings being reproduced at [16] above). First, that the appellant had not been afforded procedural fairness in respect of those findings. Second, that the arbitrator had failed to provide legally adequate reasons for those findings.
4. Ground 2 also rolled up two matters ‑ this time to the arbitrator's factual findings at arbitrator's reasons [69] (those findings being reproduced at [19] above). First, that the arbitrator had required an unnecessarily high level and exactness of proof in respect of those findings. This, in substance, was an allegation that the arbitrator had misconceived or misapplied the applicable standard of proof. Second, that the arbitrator had failed to provide legally adequate reasons for those findings.
5. The appellant conceded at the hearing of the District Court appeal that ground 2 could only succeed if ground 1 was upheld [42]. As will be seen, a similar concession was made by the appellant in the present appeal.
6. The primary judge provided a concise overview of the dispute and the issues arising for determination ([1] ‑ [8]) and turned to the events of 14 December 2021 and the appellant's medical treatment ([9] ‑ [14]). His Honour considered the arbitrator's ruling that the appellant's credibility, as well as the severity of the fall and whether injury had resulted from the fall, was in issue and could be contested [15] ‑ [16]. The primary judge then turned to the issues for determination as defined by the arbitrator and the hearing before the arbitrator [17] ‑ [25]. Having considered the issues and the evidence the primary judge gave close examination to the arbitrator's reasons [26] ‑ [38].
7. The primary judge specified the grounds of appeal ([39] ‑ [42]) and noted the statutory requirement that the appeal must involve a question of law ([43] ‑ [44]). The primary judge then set out the issues for determination that arose from the grounds of appeal in the District Court appeal [45] ‑ [46].
8. This court must apply the correctness standard in determining the appeal. Accordingly, there is no point in restating the primary judge's careful and comprehensive consideration of the legal principles relevant to the grounds and the application of those principles to the circumstances of the case. It suffices to state the primary judge's conclusions.
9. The primary judge first dealt with the allegation that the appellant was not afforded procedural fairness. The primary judge held that the alleged failure by the arbitrator to afford procedural fairness to the appellant was not made out [99]. His Honour found:
   1. The arbitrator was not required to draw the appellant's attention to inconsistencies between the appellant's evidence at the arbitration hearing and the contemporaneous medical records and the medical reports [69].
   2. The appellant and his legal representatives knew at the commencement of the arbitration hearing that the extent and severity of the appellant's fall in the toilet cubicle (and whether that fall caused an injury) was in issue [75]. The arbitration was conducted on the basis that all matters were in issue concerning the extent of the appellant's fall and any injuries he suffered from that fall [96].
   3. The respondent highlighted various inconsistencies in the appellant's case and the reliability of the appellant's reporting to medical practitioners in its pre-hearing written submissions [79]. It was not reasonable for the appellant to assume, in preparing for and conducting the hearing, that inconsistencies in the appellant's account of events would not be addressed unless specifically pointed out [80]. Nor could the appellant hold a legitimate expectation that the arbitrator would warn the appellant about such matters in the absence of cross-examination or at all [81], [95].
   4. The various findings at arbitrator's reasons [49](a) ‑ (f) were open to the arbitrator in the course of assessing and marshalling the evidence [94]. The finding that those inconsistencies reflected adversely on the reliability of the appellant's evidence was reasonable and was something that the appellant could have reasonably anticipated [97]. It was open to the arbitrator to make the findings at arbitrator's reasons [48] ‑ [49] without having to warn the appellant what those findings might be or that the appellant should address those issues by other evidence or submissions [98] ‑ [99].
10. The primary judge then turned to the allegation that the reasons for the findings at arbitrator's reasons [48] ‑ [49] were legally inadequate. His Honour considered the relevant authorities ([101] ‑ [108]) before analysing whether the arbitrator's reasons were legally inadequate ([109] ‑ [127]). The primary judge was satisfied that, read fairly, the matters in arbitrator's reason [49](a) ‑ (j), taken together, provided a sufficient basis for the arbitrator's finding that the appellant was not a reliable witness [110]. His Honour concluded that the arbitrator had provided adequate reasons [126]. Indeed, his Honour went further and stated 'I consider that the arbitrator's findings are properly reasoned' [127].
11. As, given the appellant's concession, ground 2 did not arise if ground 1 was not made out, the primary judge only made short observations on ground 2 [129]. His Honour concluded that ground 2 did not raise an error of law ([129], [145]) and that on the face of the arbitrator's reasons the arbitrator had not required proof of any issue beyond the normal standard of on the balance of probabilities [141]. Ground 2 was, in the primary judge's view, no more than an impermissible attempt to challenge a factual finding made at [69] of the arbitrator's reasons [135], [145].
12. The primary judge made orders that leave to appeal was refused and the appeal was dismissed.

1. The Workers' Compensation and Injury Management Act 1981 had been repealed by the Workers Compensation and Injury Management Act 2023 (WA) by the time of the District Court's orders dismissing the appeal from the arbitrator's decision. An appeal lies to this court from the District Court's orders pursuant to s 79 of the District Court of Western Australia Act 1969 (WA). However, the 1981 Act and the 2023 Act modify the appeal right in similar ways.[6] Essentially an appeal to this court is available only if: (1) the appeal relates to a question of law; and (2) this court grants leave to appeal.
2. There is no material difference in the modifications effected by the 1981 Act and the 2023 Act. Accordingly, there is no need to determine whether the modification to s 79 of the District Court of Western Australia Act is provided for by s 254 of the 1981 Act read with s 37 of the Interpretation Act 1984 (WA) or s 393 of the 2023 Act read with s 546 or s 575 of the 2023 Act. The better view is that s 393 of the 2023 Act applies since the District Court appeal proceedings were a 'pending dispute proceedings' that continued and were to be dealt with under the 2023 Act. See Workers Compensation and Injury Management Act 2023 s 571 and s 575. But whether the modification is grounded in the 1981 Act or the 2023 Act, it remains the position that the appellant requires leave to appeal and the appeal must relate to a question of law.
3. There are four grounds of appeal:[7]

1. His Honour erred in law in finding (at [99]) that the arbitrator did not fail to afford procedural fairness to the appellant in relation to the arbitrator's findings at [48] and [49] ... 2. His Honour erred in law in finding (at [127] and [128]) that the arbitrator provided adequate reasons for her decision ... 3. His Honour erred in law in finding (at [145]) that Ground 2 in the appeal below did not raise a question of law when:

(a) the arbitrator required an unnecessarily high level of satisfaction and exactness of proof in finding (at [68]) that she was not certain what physiological change was encompassed by the phrases 'soft tissue injury' and 'mechanical trauma' when certainty was not required; and
>
> (b) that comprised an error of law on the arbitrator's part.

1. His Honour erred in law in finding (at [145]) that Ground 2 in the appeal below did not raise a question of law when:

(a) the arbitrator failed to address in her reasons:

(A) the meaning of the phrase used by Dr Heng Tan, 'soft tissue contusion injury', and whether that was sufficient to establish an 'injury' as defined in the legislation; and

(B) the evidence of Dr John Salmon, Specialist in Pain Management, that the appellant had pronounced diffuse neural sensitivity related pain syndrome resulting from an initial soft tissue injury; and

(b) those matters comprised a failure to provide adequate reasons amounting to an error of law on the arbitrator's part.

1. Grounds 1 and 2 in the appeal in this court essentially mirror ground 1 in the District Court appeal. Grounds 3 and 4 essentially repackage ground 2 in the District Court appeal by teasing out ground 2 as advanced in the District Court into its discrete strands.
2. The appellant accepted, at the appeal hearing, that grounds 3 and 4 could not succeed unless one or both of grounds 1 and 2 were upheld.[8] That concession was consistent with the appellant's position before the primary judge (see [30] above). In the circumstances it is difficult to understand why grounds 3 and 4 were raised at all. If the appellant succeeded on ground 1 or ground 2 then grounds 3 and 4 were unnecessary. However, if the appellant failed on grounds 1 and 2 no material error was disclosed even if the appellant succeeded on ground 3 or ground 4. Apparently recognising this to be the case, counsel for the appellant chose not to develop grounds 3 and 4 at the app[9]al hearing.9

1. The appellant asserted that it was in the interests of justice that there be leave to appeal as:
   1. The primary judge's decision was wrong or attended with sufficient doubt as to justify leave.
   2. Substantial injustice would be done by leaving the decision unreversed.
2. Leave to appeal ought to be refused if the appeal does not relate to a question of law. The statutory modification to s 79 of the District Court of Western Australia Act requires that any appeal from the primary judge's order be of that character. The respondent contended that the appeal raised no issue of law. The respondent contended that, properly understood, the appellant sought to argue matters impugning factual findings made by the arbitrator. It was said that the grounds of appeal failed to clearly identify any alleged errors of law on the part of the primary judge.
3. A court, tribunal or statutory decision-maker does not make an error of law simply because the court, tribunal or statutory decision-maker finds facts wrongly or on a doubtful basis: Australian Broadcasting Tribunal v Bond.[10] In that respect, if a ground of appeal, properly analysed, does not relate to a question of law, linguistic gymnastics in the formulation of the ground cannot alter the position: Azzopardi v Tasman UEB Industries Ltd;[11] Paridis v Settlement Agents Supervisory Board.[12]
4. While, as argued, much of the appellant's focus in the present appeal was on supposed deficiencies in the arbitrator's fact-finding, we accept that each ground of appeal relates to a question of law. The gist of the appeal was a contention that the primary judge erred in law in various respects by failing to recognise that the arbitrator made various errors of law. We accept that the appellant's complaints as to the arbitrator's decision are grounded in alleged errors of law. With ground 1, so far as the appellant alleged a denial of procedural fairness, the ground related to a question of law, namely, whether there was a failure on the part of the arbitrator to afford procedural fairness to the appellant: Waite v Alcoa of Australia Ltd.[13] The legal adequacy of the arbitrator's reasons ‑ being the subject matter of ground 2 and ground 4 ‑ self‑evidently relates to a question of law: Bowles v Department of Justice;[14] Panegyres v Medical Board of Australia.[15] As to ground 3, whether the arbitrator applied the correct standard of proof is a question of law: Panegyres v Medical Board of Australia [260].
5. Accordingly, we reject the respondent's submission that the grounds of appeal do not relate to questions of law.
6. Apart from the requirement that the appeal relate to a question of law, the power to grant leave to appeal in the present context is not expressly confined. Leave to appeal should be granted if, in all the circumstances, it is in the interests of justice that there be a grant of leave. It is well established that relevant matters include, but are not limited to, whether the decision below was wrong, or attended with sufficient doubt to justify leave, and whether a substantial injustice would be done by leaving the decision unreversed. See Engine Protection Equipment Pty Ltd v Miller;[16] Waite v Alcoa of Australia Ltd [78]; Dodson v Woolworths Group Ltd.[17]
7. The requirement of leave to appeal is not a mere procedural nicety. It is an important legislative restraint on the right to appeal as conferred by the workers' compensation legislation. See, albeit in a different statutory context, the recent observations of this court in Mineralogy Pty Ltd v Citic Limited.[18] The requirement of leave to appeal acts as a filter or control device restricting a litigant's ability to pursue an appeal in relation to decisions of the kind made by the arbitrator. Such a filter or control device serves a critical function in seeking to provide for the resolution of such disputes in a manner that is fair, just, economical, informal and quick. A second appeal to this court ‑ after there has already been an appeal from an arbitrator's decision to a judge of the District Court ‑ is inimical to three of those objects.
8. The present case does not involve an issue of principle let alone a question of general public importance. The case for leave to appeal must be grounded in supposed substantial injustice to the appellant himself. In such circumstances a litigant who has failed before both the arbitrator and the District Court will ordinarily have difficulties in establishing that the interests of justice warrant leave to appeal to this court to reventilate arguments which failed in the primary appeal to the District Court. Leave to appeal to do no more than reagitate arguments rejected in the District Court ought not to be forthcoming as a matter of course. Even if, as in this case, substantive rights are involved, it is material that a litigant has already availed himself or herself of one appeal right. This court will require a reasonably clear case of alleged legal error if it is to be satisfied that the decision is attended with sufficient doubt to justify leave. That is all the more so where, as in this case, the primary judge has identified the applicable legal principles in orthodox terms to which no exception is taken, meaning that any error could only be one of application of those legal principles to the facts of the case.
9. In the present case we are not satisfied that there is a reasonably clear case of alleged legal error that justifies leave to appeal. The question of leave to appeal was referred to the appeal hearing. Accordingly, the court has heard full argument on the merits of the appeal. Having considered the merits of the appeal we would ‑ for the reasons that follow ‑ dismiss the grounds of appeal advanced by the appellant. It follows that leave to appeal must be refused and the appeal must be dismissed.

Ground 1 - the alleged denial of procedural fairness Applicable principles

1. The arbitration was conducted under div 4 of pt XI of the Workers' Compensation and Injury Management Act 1981. Arbitration was provided for by pt XI of the 1981 Act as one means for the determination of disputes between parties involved in workers' compensation matters. The Act sought to do so 'in a manner that is fair, just, economical, informal and quick' (s 3(d)). This court has previously identified a legislative intent:

to establish a system for resolution of compensation disputes which is timely, cost effective, accessible and in which arbitrated disputes are determined according to their substantial merits with as little formality and technicality as practicable: River Hill Contracting Pty Ltd v Moore.[19]

1. The object of pt XI was provided for in s 177 of the 1981 Act. Relevantly, in the case of arbitration, an object was to enable disputes to be determined 'according to their substantial merits with as little formality and technicality as practicable' (s 177(1)(e)). An arbitrator was to have regard to the object of pt XI when performing his or her functions (s 177(2)). The arbitrator's duty was to determine the matter or matters in dispute in accordance with the Act and the arbitration rules (s 185(1)).
2. The arbitrator was not bound by the rules of evidence ‑ being able to inform himself or herself on any matter as the arbitrator thought fit ‑ and was to act according to equity, good conscience and the substantial merits of the case without regard to technicalities and legal forms (s 188(2) ‑ (3)). However:

An arbitrator is bound by rules of natural justice except to the extent that this Act authorises, whether expressly or by implication, a departure from those rules. (s 188(1))

1. The appellant submitted that an arbitrator under the Workers' Compensation and Injury Management Act 1981 fulfils a judicial function and is, subject to the Act, bound to act judicially in the discharge or his or her duties and functions.
2. It is not necessary to examine the extent to which this overly broad proposition ought to be accepted. The submission relied on Summit Homes v Lucev.[20] That decision concerned a different workers' compensation dispute determination system, one previously in force under the Act. For present purposes it suffices that s 188(1) of the 1981 Act provided that, except where a departure was otherwise authorised by the Act, an arbitrator was bound by the rules of natural justice. Neither party suggested that the exception had any relevant application in the present case. It follows that an arbitrator conducting an arbitration under div 4 of pt XI of the Workers' Compensation and Injury Management Act 1981 was obliged to afford procedural fairness to the parties.
3. The authorities establish the following general propositions in relation to affording procedural fairness to a litigant:
   1. What is required by procedural fairness is a fair hearing, not a fair outcome: SZBEL v Minister for Immigration and Multicultural and Indigenous Affairs.[21]
   2. To say that a court, tribunal or statutory decision-maker is obliged to afford procedural fairness is only the first step of analysis. The second step is to identify the content of the requirements of procedural fairness. It is the second step that is critical in most cases: Kioa v West.[22]
   3. The precise content of the requirements of procedural fairness in any particular case will depend critically upon the statutory framework within which the relevant power falls to be exercised and the facts and circumstances of the particular case: SZBEL [26].
   4. The rules of procedural fairness do not have immutably fixed content but rather are flexible. The content of procedural fairness will vary according to the circumstances of the particular case. Procedural fairness is essentially practical; it is not an abstract concept. The concern of the law is the avoidance of practical injustice. What is necessary to avoid practical injustice will depend on the circumstances. See Re Minister for Immigration and Multicultural and Indigenous Affairs; Ex parte Lam;[23] HT v The Queen.[24]
   5. One aspect of procedural fairness is that a litigant must be given a 'reasonable opportunity' of being heard, ie of appearing and presenting its case by evidence, information and submissions. It is assumed, as a general rule, that opposing parties will know what case an opposite party seeks to make and how that party seeks to make it: HT v The Queen [17].
   6. Similarly, a court, tribunal or statutory decision-maker should not make an adverse finding relevant to a person's rights, interests or legitimate expectations unless the court, tribunal or statutory decision‑maker has warned that person of the risk of that finding being made or unless the risk necessarily inheres in the issues to be decided: Re Refugee Review Tribunal; Ex parte Aala.[25]
   7. The application of the requirements of procedural fairness to a court or tribunal requires analysis of the procedures of the court or tribunal and the legislation and rules which govern them: Assistant Commissioner Condon v Pompano Pty Ltd.[26]
   8. Ordinarily, in order to ground relief, a failure to comply with the requirement to afford procedural fairness must have been material ‑ it must have deprived the party of the possibility of a successful outcome: Stead v State Government Insurance Commission;[27] Nobarani v Mariconte.[28]
4. Something more should be said about the fifth and sixth propositions recited above having regard to aspects of the appellant's argument on the appeal.
5. A litigant is, ordinarily, entitled to have brought to its attention the critical issues or factors on which a decision is likely to turn so as to give the litigant an opportunity to deal with those issues or factors: Commissioner for ACT Revenue v Alphaone Pty Ltd.[29] However, a court, tribunal or statutory decision‑maker is not usually required to disclose to a person to whom procedural fairness must be accorded the court's, tribunal's or statutory decision-maker's mental processes, provisional views or proposed conclusions before a final decision is made: Commissioner for ACT Revenue v Alphaone Pty Ltd (591), (592); Apache Northwest Pty Ltd v Agostini [No 2].[30] To the contrary as this court stated in McKay v Commissioner of Main Roads:

Generally speaking in litigation, the parties must anticipate combinations and permutations of various findings and adduce evidence and make submissions at the trial on all the potential findings of fact on the issues litigated ... [although] procedural fairness may require the judge to hear the parties further if certain matters emerge in the judge's consideration of the case after trial which the judge regards as potentially dispositive but in relation to which, in all the circumstances, it is to be inferred that the parties did not have a proper opportunity to address at trial.[31]

1. This passage was referred to with approval by this court in its recent decision of Davie v Manuel.[32]
2. These decisions are consistent with the High Court's recognition in SZBEL that procedural fairness does not require a decision‑maker to give a litigant a running commentary about what the decision‑maker thinks about the evidence that is given [48]. In SZBEL the High Court also quoted with approval what was stated by Lord Diplock in F Hoffmann-La Roche & Co AG v Secretary of State for Trade and Industry:

[T]he rules of natural justice do not require the decision maker to disclose what he is minded to decide so that the parties may have a further opportunity of criticising his mental processes before he reaches a final decision. If this were a rule of natural justice only the most talkative of judges would satisfy it and trial by jury would have to be abolished.[33]

1. It may be necessary, in a particular case, for a proposed conclusion to be disclosed and for a litigant likely to be adversely affected by that conclusion to be given an opportunity to make submissions on that adverse conclusion. That may be the case where the adverse conclusion 'could not reasonably be expected': Victims Compensation Fund Corporation v Nguyen;[34] or the adverse conclusion is not 'obvious and natural' or would not 'obviously be open' on an evaluation of the material known to be before the decision‑maker: Commissioner for ACT Revenue v Alphaone Pty Ltd (591), (592). These are situations where, to use McHugh J's words in Ex parte Aala, the risk of such an adverse conclusion does not 'necessarily inhere' in the issues to be decided.
2. Whether the circumstances require that the court, tribunal or statutory decision-maker raise a proposed conclusion with the parties involves matters of degree in the exercise of evaluative judgment.

The appellant's contention that he was denied procedural fairness

1. Ground 1 concerns the findings at arbitrator's reasons [48] and [49] ‑ in particular that, having assessed the appellant as an unreliable witness for the reasons enumerated at arbitrator's reasons [49], the appellant did not fall with any force so as to cause injury.
2. The appellant complains that the arbitrator made various findings in the sub-pars to arbitrator's reasons [49] that were not the subject of opening or closing submissions by the respondent, were not put to the appellant in cross-examination and were not put to the parties by the arbitrator before the arbitrator's decision. The appellant accepts that, at the arbitration proceedings, counsel for the respondent put the credibility of the appellant's account in issue in a general sense. There was, in particular, a contest raised as to the severity of the appellant's fall. But, in the appellant's submission, many of the matters raised in arbitrator's reasons [49] were not raised by the respondent (whether in submissions or cross-examination) or by the arbitrator.
3. The appellant's contention that there had been a denial of procedural fairness was developed by reference to the findings at arbitrator's reasons [49](b) ‑ (f). The appellant submitted that:
   1. The only possible relevance of the matters referred to at arbitrator's reasons [49](b) ‑ (f) was as prior inconsistent statements. However, if to be so used, it was necessary that the relevant statement be put to the appellant so that he had an opportunity to admit or deny them; and, if admitted, to provide a reason or explanation for any apparent inconsistency.
   2. The arbitrator did not consider an available alternative explanation for the prior inconsistent statement referred to at arbitrator's reasons [49](c) (namely that the medical practitioner might have reported the statement attributed to the appellant incorrectly or inaccurately).
   3. It is conceivable that the descriptions at arbitrator's reasons [49](d) (as to what the appellant slipped on) were not inconsistent as the appellant may have slipped on slippery, soapy water which was present on the floor.
   4. On their face the statements recorded at arbitrator's reasons [49](e) were not inconsistent (the statements concerning what was entailed in the slip-and-fall).
   5. There was no apparent inconsistency in the statements referred to at arbitrator's reasons [49](f) (the statements as to how the appellant landed as a result of the slip-and-fall).
4. In contending that there had been a denial of procedural fairness, the appellant argued that, in all of the circumstances, it could not have been reasonably anticipated that the arbitrator would rely on those matters.

1. The arguments advanced by the appellant in support of ground 1 were, with one exception, the same arguments as the appellant relied on before the primary judge in contending that there had been a denial of procedural fairness. The exception is that, before the primary judge, the appellant also relied on the finding at arbitrator's reasons [49](a). The submission that the arbitrator's finding at [49](a) involved a failure to afford procedural fairness to the appellant was not pursued in this court. Accordingly, in renewing the contention that the arbitrator's decision was tainted by a denial of procedural fairness, the appellant relied on a sub-set of the arguments raised before the primary judge.
2. The primary judge rejected the appellant's contention that there had been a denial of procedural fairness for the reasons summarised at [34] above. The primary judge's conclusion was correct for the reasons that his Honour gave. While, in this respect, the primary judge's reasons for rejecting the appellant's contention of a denial of procedural fairness are more than sufficient - and for reasons of judicial economy it is tempting to simply adopt the primary judge's reasons ‑ having developed the relevant legal principles above it is appropriate to explain why the appellant's arguments in support of ground 1 fail in light of those principles.
3. It is convenient to start with the appellant's submissions summarised at [66.2] - [66.5] above. There is a common problem with each of these matters. On their face each of these submissions is concerned with the correctness of the reasoning it relates to in the relevant aspect of the arbitrator's reasons (at [49](c) ‑ (f) thereof). Accordingly, of themselves these matters do not bespeak any denial of procedural fairness. There is not a denial of procedural fairness in failing to consider an available alternative explanation (as to arbitrator's reasons [49](c)) or in coming to an arguably incorrect conclusion (as to arbitrator's reasons [49](d) ‑ (f)).
4. In oral submissions, when pressed that it appeared that these arguments appeared to be going to the logic or merits of the arbitrator's reasoning and conclusions rather than a failure to afford procedural fairness, counsel for the appellant eschewed any attempt to persuade this court that the arbitrator's finding was incorrect ‑ counsel did not seek to challenge the logic or merits of the arbitrator's reasoning and conclusions. Counsel was correct to approach the matter in this way; the contrary position would have been untenable given that the allegation is one of denial of procedural fairness. Counsel suggested, however, that the point being made as to the logic or merits of the arbitrator's reasoning and conclusions was relevant to whether the appellant reasonably ought to have been on notice that those matters would have been relied on in relation to a general finding on the reliability of the appellant's evidence.
5. So understood, whether the complaints summarised at [66.2] ‑ [66.5] above have merit is bound up in the appellant's overriding submission as to the extent to which the appellant was on notice as to the challenge to his credibility and reliability.
6. Arbitration under div 4 of pt XI of the Workers' Compensation and Injury Management Act 1981 was not conducted on pleadings. The relevant procedural steps for such arbitration proceedings were provided for in the Workers' Compensation and Injury Management Arbitration Rules 2011 (WA). Among other things, provision was made for material to be lodged and served with the application (r 25) and any reply (r 29). In summary, among other things, parties were required to exchange copies of all documents, material and information ‑ including medical reports ‑ that they proposed to adduce in evidence in determination of a dispute. Also, a reply had to state concisely but with full particularity what parts of an application were disputed, giving full particulars of the grounds on which the application is disputed and the issues for determination by the arbitrator (r 27).
7. The respondent's reply in the arbitration proceedings[35] stated that no part of the application or issues were admitted.[36] In stating the issues for determination the respondent disputed that the appellant had sustained an injury as there was no clear diagnosis and no adequate evidence of an injury (par 3). The respondent submitted that the application ought to be dismissed and put the appellant to the proof of his claim (pars 10 ‑ 11).
8. It is apparent, from a directions hearing on 28 November 2022, that the appellant's honesty and credibility was in issue in the arbitration proceedings.[37] Any doubt in this regard was dispelled prior to the hearing before the arbitrator when the respondent filed and served written submissions.[38] In response to a submission that the appellant's version of events was 'uncontested' (as the respondent had provided no evidence to dispute the events of 14 December 2021)[39] the respondent stated:

[T]he respondent says that the use of the word 'uncontested' is inappropriate in all of the circumstances. The alleged incident was unwitnessed and one significant issue which clearly needs to be determined in this application is [the appellant's] credibility in terms of the accident, whether it caused the injuries asserted and the alleged incapacity. Crucially arising within that factual matrix is the issue of causation in terms of both his alleged physical and psychological injuries. (par 1) (emphasis added)

1. The respondent's pre-hearing written submissions went on to refer to:
   1. Inconsistencies between what the appellant had told his treating psychologist and a consulting psychiatrist as to prior psychological symptoms and materials in other proceedings (pars 2 ‑ 8).
   2. The circumstance that the appellant's honesty was a matter for the arbitrator in the proceedings (par 14).
   3. The appellant's alleged physical symptoms being significantly affected by the unreliability of the appellant's evidence of psychological disability ‑ 'all of the evidence' indicating that the appellant had suffered no significant physical injury (par 17).
   4. Aspects of the medical reports which were said, in substance, to lead to a conclusion that there was no physical basis for the appellant's complaints (pars 17 ‑ 30, 32).
   5. The physical and psychological position of the appellant in the three-months post-accident being 'opaque' given 'the apparent lack of credibility' of the appellant (par 32).
2. More generally the respondent submitted that the appellant had failed to discharge his onus of proof in respect of his physical symptoms 'in any respect at all' (par 16).
3. The respondent's written submissions excited an objection at the commencement of the arbitration hearing. Counsel for the appellant objected to the submission that the appellant's credibility in terms of the accident was contested; it was said there was no contest, as far as counsel could see, from the reply or direction orders (ts 4). That submission was misconceived given what has been referred to above. Counsel for the respondent replied in robust terms. It was made clear that, on the respondent's case, the appellant had not been telling the truth throughout the entirety of his treatment and his credibility was very much in issue (ts 5). Counsel for the appellant accepted that but sought to rely on an apparent admission in the respondent's written submissions. Counsel for the respondent clarified that there was an admission that the appellant slipped and fell but said that the circumstances in which the appellant slipped and fell, and the degree of severity of the fall, was very much in issue (ts 5). The objection then fell away.
4. After confirming that the objection had been dealt with the arbitrator clarified that:

I'd just like to say, well, in the terms of this whole hearing, it will come down to how [the appellant] presents himself under cross‑examination, and that will be for me to decide, ultimately. (ts 5)

1. Counsel for the appellant did not disagree with that statement but said:

Of course we say, ma'am, just to be clear, that there's more to it than simply an assessment of how he presents - how the [appellant] presents on the witness stand, just to be clear about the [appellant's] case. (ts 6)

1. In so doing counsel for the appellant acknowledged, correctly, that the arbitrator would undoubtedly have regard to the contemporaneous documentary evidence as well as the reports from the medical practitioners. Counsel accepted as much at the appeal hearing.[40] Those materials were potentially useful for the appellant's case. But, as has been seen, they were also potentially adverse to the appellant's case.
2. The appellant provided a relatively short oral opening statement (ts 6 ‑ 12). Counsel for the appellant relied on aspects of the medical reports. Among other things, counsel for the appellant observed how, by one of the reports relied on by the respondent, there was a challenge to the appellant's credibility (ts 10). Counsel for the appellant also acknowledged the respondent's pursuit of credibility issues in a broader sense (ts 11).
3. The appellant's evidence‑in‑chief was confined to confirming the correctness of his witness statements (ts 15 ‑ 17). The appellant was then cross-examined in a way that clearly put the credibility, reliability and accuracy of his account in issue (ts 18 ‑ 41). The appellant himself recognised that this was so; he protested that counsel for the respondent was calling him a liar (ts 23, 41; see also ts 24). It is true that, as the appellant says in support of ground 1, counsel for the respondent did not touch on the matters referred to at arbitrator's reasons [49](b) ‑ (f) as prior inconsistent statements. However, there was cross‑examination on apparent omissions in the appellant's reported history in other reports (ts 24 - 25, 30 ‑ 34, 39 ‑ 40).
4. Counsel for the respondent did not provide an oral opening and, in closing, relied on the respondent's written submissions. Counsel made it plain that, from the respondent's perspective, the issue for the arbitrator was 'very much about credibility' and 'the nature and the extent of the injuries received' (ts 50; see also ts 56). While, again, counsel for the respondent did not refer to the matters referred to at arbitrator's reasons [49](b) ‑ (f), counsel referred to the omissions in what the appellant reported to the medical practitioners (ts 55, 56).
5. In reserving her decision, the arbitrator expressly informed the parties that she would be reading 'all the documents' (ts 61).
6. There was no submission, in support of ground 1, to the effect that the appellant was not on notice that the arbitrator would be assessing the credibility, reliability and accuracy of the appellant's evidence as to the circumstances of his fall in the toilet cubicle ‑ in particular, the degree of severity of the fall and whether the appellant in fact suffered an injury. To the contrary, it was plain that these matters were very much in contest. Any doubt in this regard could not have survived the interchange at the commencement of the arbitration hearing. In truth, however, the respondent had at all times made it plain that the appellant was being put to proof, no part of the appellant's claim being admitted, and that the veracity of the appellant's account of the slip-and-fall was in issue.
7. The argument in support of ground 1 instead focused on the absence of any specific challenge to reliability based on the inconsistencies catalogued by the arbitrator at [49](b) ‑ (f) of the arbitrator's reasons.
8. The arbitrator identified the inconsistencies from a close consideration of the medical reports. The quoted statements at [49](b) ‑ (f) are statements attributed to the appellant by the various medical practitioners in their reports. The medical reports relied on by the arbitrator were available to the appellant and his legal representatives at all material times. The Workers' Compensation and Injury Management Arbitration Rules ensured that was the case. There is no suggestion that the reports themselves caught the appellant by surprise. It was, in this respect, always open to the appellant to deal with the apparent inconsistencies in the medical reports. Indeed, in at least one respect the appellant sought to do so at the arbitration hearing. Counsel for the appellant referred to a decision in which a judge of the District Court stated that it was 'well‑known and hence accepted that doctors sometimes receive and/or report subjective [sic] histories incorrectly or inaccurately' (ts 11). It might be that this was brought about by the respondent's written submissions so far as those submissions highlighted particular alleged inconsistencies. But the same point arose as to any and all inconsistencies in what the appellant had said as to the events of 14 December 2021 and his alleged injuries.
9. At this juncture it becomes necessary to evaluate the appellant's argument that the arbitrator's conclusions at [49](b) ‑ (f) so lacked logic or were so without merit that, viewed objectively, the appellant was never on notice that such matters might be relied on by the arbitrator in relation to a general finding on the reliability of the appellant's evidence.
10. We reject the appellant's submission to this effect. We are well satisfied that it was reasonably open to the arbitrator to conclude that there were inconsistencies as specified at arbitrator's reasons [49](b) ‑ (f) on the face of the different versions of the material events as attributed to the appellant. In the circumstances of the arbitration proceedings, as we have summarised them, it was obvious or natural to expect that the arbitrator might have regard to such considerations. It is exceedingly common for triers of fact to assess the veracity of a person's evidence by having regard to the extent to which he or she has kept to a consistent version of events. Moreover, in the present case the respondent relied on other inconsistencies in what the appellant was reported to have said to treating and consulting medical practitioners. So far as there were arguable inconsistencies in the medical reports ‑ and arguable inconsistencies between the appellant's evidence and the medical reports - the risk of adverse conclusions of the kind reached at arbitrator's reasons [49](b) ‑ (f) necessarily inhered in the issues to be decided by the arbitrator.
11. Once it was accepted that there were inconsistencies ‑ a matter for the arbitrator rather than this court ‑ it was reasonably open to the arbitrator to conclude that the appellant's evidence as to the severity of the slip‑and‑fall was unreliable. That is all the more so given the additional findings at arbitrator's reasons [49](g) ‑ (h) (none of which are said to be tainted by a failure to afford procedural fairness).
12. The remaining matter relied on by the appellant in support of ground 1 is the respondent's failure to observe the rules for cross‑examination as to prior inconsistent statements. Counsel for the respondent did not comply with the procedure mandated by s 21 of the Evidence Act 1906 (WA). But compliance with s 21 was not required in circumstances where the arbitrator was not bound by the rules of evidence. There is, undoubtedly, much to be said for the adoption of the procedure under s 21 whenever use is sought to be made of a prior inconsistent statement. Those rules ensure fairness and assist a trier of fact to evaluate the significance and weight to be given to a prior inconsistent statement. However, in circumstances where an arbitrator conducting an arbitration under div 4 of pt XI of the Workers' Compensation and Injury Management Act 1981 is not bound by the rules of evidence, it goes too far to say that if the statements were to be used as prior inconsistent statement it was necessary that they be put to the appellant (compare the appellant's submission as reproduced at [66.1] above).
13. It may be accepted that the omission to comply with the procedure under s 21 of the Evidence Act has to be taken into account in determining whether there was a denial of procedural fairness so far as the arbitrator arrived at the findings at arbitrator's reasons [48] and [49]. Having done so, given the matters we have referred to previously, we are satisfied that the arbitrator's decision did not involve a denial of procedural fairness. The findings that the appellant complains of in advancing ground 1 necessarily inhered in the issues to be decided by the arbitrator. The appellant was afforded a reasonable opportunity to present his case on those matters ‑ and, insofar as counsel for the appellant made the submission that the appellant's medical practitioners may have reported statements attributed to the appellant incorrectly or inaccurately, availed himself of that opportunity. There was, in all the circumstances of the arbitration proceedings, no practical injustice involved in the arbitrator arriving at the findings at arbitrator's reasons [48] and [49].
14. Ground 1 fails.

Ground 2 - the alleged legal inadequacy of the arbitrator's reasons Applicable principles

1. The generally applicable principles dealing with the adequacy of reasons for decision are well-established. There is a recent recitation of the principles and authorities in Tabloid Pty Ltd v Pringle.[41] See more generally Kipoi Holdings Mauritius Ltd v Kirman [No 4].[42] For present purposes it suffices to adopt, without reproduction, what is stated in those decisions.
2. In evaluating the adequacy of reasons for decision the critical question is whether the essential path of reasoning to the impugned conclusion is disclosed in sufficient detail and with sufficient certainty to meet the twin objects that: (1) the litigant knows why he or she was unsuccessful; and (2) an appeal court may determine whether the decision involved appellable error. See Tabloid Pty Ltd v Pringle [67].
3. As was stated in Browne v Browne:

The principles relevant to an evaluation of the adequacy of reasons are well established and include the following:

(1) Reasons for decision need not be lengthy or elaborate.

(2) Reasons should disclose the intellectual process that led to the decision in sufficient detail and with sufficient certainty to enable the litigant to know why they were unsuccessful and to enable an appeal court to determine whether the decision involved appellable error.

(3) It is certainly not necessary to refer to every submission advanced by a party. However, a tribunal or court must engage with the central element(s) of a losing party's case and explain why that case fails. Considering that party's submissions is an aspect of what procedural fairness requires.

(4) In determining the adequacy of the reasons, the reasons must be read as a whole, and, if necessary, considered in the context of the evidence. An appellate court may take into account what can legitimately be inferred from the reasons. Whether reasons are adequate will depend upon the circumstances of the case and the matters that arose for the judge's consideration.[43] (citations omitted)

1. As to the last point, the authorities accept that the content and detail of reasons will vary according to the nature of the jurisdiction that is being exercised and the particular matter the subject of the decision: Wainohu v New South Wales;[44] DL v The Queen.[45]
2. Two further matters should be noted.
3. First, it is wrong to equate the requirement that reasons be legally adequate with a requirement that reasons be factually and legally correct. In that respect, as will be seen, much of the appellant's argument in support of ground 2 conflated legal adequacy with correctness. Reasons for decision may be legally adequate but nonetheless contain factual or legal errors. Indeed, as was observed in Tabloid Pty Ltd v Pringle [79], reasons may even demonstrate that a decision-maker has reached a conclusion that is legally unreasonable or illogical but still satisfy the requirements of legal adequacy in the sense discussed in the authorities.
4. Second, it is recognised that no reasons can ever state all of the pertinent factors; nor can they express every feature of the evidence that causes a decision-maker to prefer one factual conclusion over another: Fox v Percy [41]. In that respect it is not necessary to give 'reasons for reasons' ‑ at some point a decision‑maker 'reaches bedrock': Child and Adolescent Health Service v Mabior.[46]
5. The arbitrator's duty to provide reasons was governed by s 213 of the Workers' Compensation and Injury Management Act 1981. Accordingly, the general law principles as to adequacy of reasons, as previously discussed, are to be applied in light of and subject to s 213. Relevantly, by s 213(4), the reasons for an arbitrator's decision:

(a) need only identify the facts that the arbitrator has accepted in coming to the decision and give the reasons for doing so; and

(b) need only identify the law that the arbitrator has applied in coming to the decision and give the reasons for doing so; and

(c) need not canvass all the evidence given in the case; and

(d) need not canvass all the factual and legal arguments or issues arising in the case.

1. In this respect, s 213(4) of the Workers' Compensation and Injury Management Act 1981 mirrored the statutory requirements as to reasons for judgment in the Magistrates Court as set out in s 31(1) of the Magistrates Court Act 2004 (WA).
2. Section 213(4) of the Workers' Compensation and Injury Management Act 1981, and its equivalent in s 31(1) of the Magistrates Court Act, was considered by Murphy JA (Pullin and Newnes JJA agreeing) in Velez Pty Ltd v Tudor.[47] By reference to other decisions of the court the following emerges from Velez Pty Ltd v Tudor:
   1. Section 213 has to be considered in the factual context in which it was enacted. Arbitrators are frequently called on to give reasons in disputes where there will be a significant number of conflicting medical reports. By implication the legislature was intending that an arbitrator should not be required to engage in an exhaustive process of specifying which opinions were rejected and the reasons for their rejection [68] (referring to Sotico Pty Ltd v Wilson).[48]
   2. The realities of pressure of work and limited time in these jurisdictions must be acknowledged. The statutory provisions obviate the need for the relevant decision‑maker to canvass all the evidence given in the case and to canvass all the factual and legal arguments or issues arising in the case. These dispensations recognise the summary nature of the proceedings [69] (referring to Manonai v Burns).[49]
   3. In identifying the facts accepted and the reasons for doing so, and the law applied and the reasons for doing so, the arbitrator will still be obliged to expose the reasoning process linking them and justifying the ultimate result [70].
3. Section 31(1) of the Magistrates Court Act was also considered by this court in Duluxgroup (Australia) Pty Ltd v Chapple.[50] In that decision the court pointed out that s 31(1) provided statutory recognition of what sufficed for legally adequate reasons when providing reasons for judgment in a case in the Magistrates Court: Duluxgroup (Australia) Pty Ltd v Chapple [49](1). In the same way, the practical content of the arbitrator's duty to give reasons was affected by the nature of the jurisdiction being exercised by the arbitrator and the terms of s 213(4) of the Workers' Compensation and Injury Management Act 1981.
4. It is not simply that s 213(4) prescribed the extent of the content and detail required of the arbitrator's reasons. Two further matters are relevant. First, as has already been mentioned in addressing the question of procedural fairness, the relevant workers' compensation legislation sought to establish a system for determining workers' compensation disputes that was accessible, cost effective and timely in which arbitrated disputes were determined according to their substantive merits with as little formality and technicality as practicable. The adequacy of an arbitrator's reasons is to be assessed in the context of the informal and timely way in which it is expected that an arbitrator will deal with a dispute for determination. It would not, for example, be appropriate to find inadequacy in an arbitrator's reasons due to mere infelicities in language. An arbitrator may be expected to express his or her conclusions with an economy that is consistent with the nature of the dispute determination system established by the legislation.
5. Second, the ambit of any appeal from the arbitrator's decision is confined by the terms of the workers' compensation legislation. An appeal must 'involve' a question of law (on an appeal to the District Court) or 'relate' to a question of law (on a further appeal to this court). An important function of reasons is to facilitate the exercise of the relevant statutory right of appeal. In assessing the adequacy of the arbitrator's reasons by reference to whether the reasons deprive the appellant of an effective right of appeal, due regard must be had to the limited grounds which might sustain an appeal. Importantly, no appeal lies on a pure question of fact.

1. In terms of ground 2, the appellant's contention that the arbitrator's reasons are legally inadequate was advanced by reference to arbitrator's reasons [48] and [49]. The appellant's argument in that regard is adequately summarised by the particulars provided in support of ground 2:

(i) The arbitrator's reason (at [49]) 'based on my assessment of Mr Zamora' was not adequately explained nor did the arbitrator explain how her 'assessment of Mr Zamora' led her to conclude (at [48]) that Mr Zamora's slip and fall did not cause an injury.

(ii) The arbitrator did not articulate how each of the matters set out in [49](a) - (j) supported her conclusion (at [48]) that the appellant's slip and fall did not cause an injury.

(iii) The arbitrator did not address in her reasons:

(A) the employer's admission that the appellant felt immediate pain in his back, at paragraph 1 of its outline of submissions; and

(B) the appellant's evidence of severe back pain such that he could not get up following the fall.

(iv) The arbitrator did not address in her reasons the appellant's submission that apparent inconsistencies in the medical reports were explicable on the basis that they were not recorded accurately by the doctors.

1. There are two aspects to particular (i) in support of ground 2. First, the contention that the reference to the arbitrator's 'assessment' of the appellant was not adequately explained. Second, the contention that there was no explanation as to how the assessment led the arbitrator to conclude that the slip‑and‑fall did not cause an injury. Both contentions are without merit. Neither contention establishes legal inadequacy in the arbitrator's reasons.
2. On the first aspect of particular (i), the appellant submitted that the reasons in the chapeau to arbitrator's reasons [49] were inadequate because the arbitrator did not explain what she meant by her 'assessment' of the appellant. Nor, according to the appellant, did the arbitrator set out the matters taken into account in forming that assessment. It was contended that the arbitrator's process of reasoning was not adequately exposed.
3. In context the arbitrator was plainly referring to her assessment of the credibility, reliability and accuracy of the appellant's evidence. The finding at arbitrator's reasons [49] occurs in a section headed '[m]y findings as to the slip and fall and [the appellant's] reliability'. Any doubt as to the nature of the assessment is resolved by reading the arbitrator's reasons as a whole. In particular, at arbitrator's reasons [18] the arbitrator states that her findings on the slip-and-fall 'turn on my assessment of the reliability and credibility' of the appellant (see [12] above) (emphasis added). See also arbitrator's reasons [12] where the arbitrator refers to her 'consideration' of the appellant's credibility and reliability. More generally the arbitrator's reasons make it plain that the arbitrator did not accept the reliability of the appellant's evidence as to the force of his fall. See arbitrator's reasons [18], [48], [49], [90], [93] ‑ [95].
4. As to the matters taken into account in assessing the appellant's evidence, the arbitrator commenced by articulating the approach she intended to take to the assessment [18]. The arbitrator listed 10 matters relied on in concluding that the appellant was an unreliable witness [49]. The arbitrator referred to the absence of objective evidence that the appellant suffered an injury to his back or shoulder [64] (see also [54] ‑ [63], [67]). The arbitrator then reiterated that her finding that the appellant was not a reliable witness was based on the inconsistent histories given by the appellant (arbitrator's reasons [90]) and the appellant's failure to provide accurate details of the incident and his non‑disclosure of a prior history concerning a psychological issue (arbitrator's reasons [94]).
5. There was, in the circumstances, ample disclosure of the arbitrator's intellectual process in concluding that the appellant was not a reliable witness. The arbitrator did not accept the appellant's evidence as to the circumstances of the fall on the basis that the appellant was an unreliable witness. Having concluded that the appellant's evidence ought not to be accepted, in the absence of objective evidence as to any physical injury, the arbitrator was not satisfied that the appellant fell with such force so as to cause injury. Put simply, the appellant failed to prove his case that he had suffered a compensable injury as a result of the slip‑and‑fall because his evidence was not accepted and there was no objective evidence of a physical injury. In these respects the arbitrator's essential path of reasoning is readily identifiable and appears with sufficient detail and with sufficient certainty to meet the objects specified at [96] above. So too the requirements of s 213(4)(a) of the Workers' Compensation and Injury Management Act 1981 are satisfied. The arbitrator did not accept that the appellant's fall in the toilet cubicle involved force so as to cause injury or that the appellant suffered an injury as a result of the slip‑and‑fall. The arbitrator gave legally adequate reasons for those conclusions.
6. The second aspect of particular (i) is equally misconceived. The appellant submitted that the reasons were inadequate because the arbitrator did not set out a basis for the finding that the appellant was an unreliable witness. Issue was taken with the statement that the finding was 'also informed' by the matters enumerated at arbitrator's reasons [49]. The appellant submitted that, by necessary implication, some matters were left unstated. The required content and detail for legally adequate reasons varies according to the matter the subject of the decision. Little may be required for legally adequate reasons in a simple contest of credibility as between two witnesses: Kipoi Holdings Mauritius Ltd v Kirman [No 4] [512]. That is also the case when assessing the reliability of a witness's testimony. So understood the second aspect of particular (i) fails for the same reasons as the first aspect of particular (i). As has been explained in rejecting the first aspect of particular (i), there was fulsome disclosure of the arbitrator's intellectual process in concluding that the appellant was not a reliable witness.
7. Particular (ii) misses the point. The ten matters listed by the arbitrator at [49](a) ‑ (j) are not directed to the conclusion that the appellant's slip‑and‑fall did not cause an injury. Rather, they are directed to the conclusion that the appellant's evidence was unreliable. The reasoning in this respect is self‑evident from the matters as listed. Counsel for the appellant accepted, correctly in our view, that the matters listed in [49](a) ‑ (j) provided adequate reasons for the finding that the appellant's evidence as to the circumstances of the slip‑and‑fall was unreliable.[51] As previously explained, the conclusion that the appellant's evidence was unreliable - and thus was not to be accepted ‑ led to the conclusion that the appellant failed to prove his case that he had suffered a compensable injury as a result of the slip‑and‑fall.
8. Particulars (iii) and (iv) may be dealt with together. Both particulars allege inadequacy of reasons on the basis that the arbitrator did not address certain matters. Particular (iii) concerns a supposed admission and evidence said not to have been addressed. Whether there was an admission of fact is questionable. The supposed admission was attended by the respondent's clarification that the incident was unwitnessed and a significant issue for determination was the appellant's credibility in terms of the accident and whether it caused the injuries asserted. In the circumstances the better view is that the admission did not extend any further than to acknowledge the effect of the appellant's evidence. That is all the more so where, as accepted by counsel for the appellant at the appeal hearing, in cross-examination there was an implicit challenge to the appellant's claim to have been in severe pain. Particular (iv) concerns a submission said not to have been addressed in the arbitrator's reasons.
9. At the appeal hearing counsel for the appellant eschewed any argument to the effect that the arbitrator had failed to exercise jurisdiction by not considering and determining a material issue. Once that point was reached particulars (iii) and (iv) had little scope for meaningful operation in support of a ground alleging inadequacy of reasons where, by virtue of s 213(4)(c) of the Workers' Compensation and Injury Management Act 1981, the arbitrator's reasons did not need to canvass all of the evidence, or all of the factual and legal arguments or issues, in the case. In any event, as argued, particulars (iii) and (iv) were primarily directed to the correctness of the arbitrator's reasons. That, as already explained, cannot sustain a conclusion that the arbitrator's reasons were legally inadequate.
10. In terms of particulars (iii) and (iv) in support of ground 2, the arbitrator's reasons were legally adequate insofar as the arbitrator made a factual finding, with accompanying reasons, rejecting the appellant as a reliable witness. It necessarily followed that the arbitrator did not accept the appellant's evidence of severe back pain and ‑ if there was a relevant admission ‑ that the appellant felt immediate pain following the slip‑and‑fall. There was no need, in terms of s 213(4) of the 1981 Act, for the arbitrator to address the appellant's submission that the apparent inconsistencies in the medical reports were explicable on the basis that they were not recorded accurately by the medical practitioners.
11. Ground 2 fails.

Grounds 3 and 4 - exactness of proof and alleged legal inadequacy as to reasons in relation to evidence of soft tissue injury or mechanical trauma

1. Grounds 3 and 4 fall away given the failure of grounds 1 and 2 and the appellant's concession that grounds 3 and 4 cannot establish a material error in the event that grounds 1 and 2 do not succeed. We will, however, deal with these grounds in a summary way. It is appropriate to do so insofar as the primary judge concluded that the equivalent ground in the primary appeal, namely ground 2, did not raise a question of law.
2. The primary judge was, in our respectful view, in error in concluding that ground 2 in the primary appeal did not raise a question of law. See [46] above. Whether the arbitrator applied the correct standard of proof is a question of law. So too the legal adequacy of the arbitrator's reasons as to whether the appellant had suffered a personal injury by accident involves a question of law.
3. While, in those respects, ground 2 in the primary appeal involved questions of law, the primary judge was undoubtedly correct in concluding that the appellant was in truth and reality seeking to challenge a factual finding. In form the ground raised a question of law. In substance, however, the ground challenged the arbitrator's factual finding that the appellant did not suffer a soft tissue injury or any compensable injury as a result of the slip‑and‑fall.
4. As to the first aspect of ground 2 in the primary appeal ‑ ground 3 in this court ‑ the arbitrator correctly identified the relevant standard of proof at arbitrator's reasons [15] ‑ [16] (see [12] above). There is no proper basis, reading the arbitrator's reasons fairly and as a whole, to suppose that having correctly identified the relevant standard of proof as a matter of law the arbitrator then misapplied that standard of proof in assessing the evidence. That being the case ground 3 must fail. The appellant's argument that there was such a misapplication requires this court to conclude that, contrary to the arbitrator's factual finding, there was in fact an injury within the meaning of the Workers' Compensation and Injury Management Act 1981, meaning that the arbitrator must have erred in law in requiring an unnecessarily high level of satisfaction and exactness of proof. It is not possible, through the guise of asserting a misapplication of the standard of proof, to convert an appeal on a question of fact to an appeal on a question of law any more than it is to convert a question of fact into a question of law by inverting the onus of proof: Panegyres v Medical Board of Australia [256], [260] (see also [261] ‑ [263]); Azzopardi v Tasman UEB Industries Ltd (156).
5. The second aspect of ground 2 in the primary appeal ‑ ground 4 in this court ‑ again raised a challenge to the legal adequacy of the arbitrator's reasons.
6. The arbitrator made a factual finding that the appellant had not established that he suffered a 'soft tissue injury' or a 'mechanical trauma' [69]. The challenge by ground 4 focused on evidence given by Dr Tan and Dr Salmon which the arbitrator was said to have failed to address. The challenge overlooks the arbitrator's factual finding that there was no objective evidence that the appellant suffered an injury to his back or shoulder [64] (see also [67]). Nothing in Dr Tan's evidence or Dr Salmon's evidence gainsaid that conclusion. Dr Tan first reviewed the appellant on 10 March 2022, nearly three months after the slip-and-fall. Dr Salmon saw the appellant a little earlier on 1 February 2022. In each case the medical opinion relied on the appellant's self‑reporting of the incident and subsequent symptoms such that, to be accepted, the arbitrator had to find that the information provided by the appellant was reliable [18], [90], [93]. However, as has been seen, the arbitrator found that the appellant was not a reliable witness [18], [48], [49], [90], [93] ‑ [95].
7. So understood the arbitrator provided legally adequate reasons for the factual finding that the appellant had not established that he suffered a 'soft tissue injury' or a 'mechanical trauma'. The requirements of s 213(4)(a) of the Workers' Compensation and Injury Management Act 1981 were met. Section 213(4)(c) and (d) of the 1981 Act obviated the need to canvass the additional evidence of Dr Tan and Dr Salmon that the appellant relied on in advancing ground 4.
8. Grounds 3 and 4 fail.

1. For these reasons leave to appeal must be refused and the appeal must be dismissed. Prima facie costs should follow the event and the appellant should pay the respondent's costs of the appeal, to be assessed if not agreed. If, however, either party wishes to be heard on the costs of the appeal, any costs issue will be determined on the delivery of these reasons for decision.

I certify that the preceding paragraph(s) comprise the reasons for decision of the Supreme Court of Western Australia.

[2] Zamora v OCS Services Pty Ltd [2024] WADC 77 (primary reasons).

[3] Pinpoint references in this section are to the arbitrator's reasons.

[4] Fox v Percy [2003] HCA 22; (2003) 214 CLR 118 [30] - [31].

[5] Pinpoint references in this section are to the primary reasons except where there is express reference to the arbitrator's reasons.

[6] See Workers' Compensation and Injury Management Act 1981 s 254; Workers Compensation and Injury Management Act 2023 s 393.

[7] The pinpoint references in the grounds of appeal are to the primary reasons other than where, in context, a ground is referring to one of the arbitrator's findings.

[10] Australian Broadcasting Tribunal v Bond [1990] HCA 33; (1990) 170 CLR 321, 356.

[11] Azzopardi v Tasman UEB Industries Ltd (1985) 4 NSWLR 139, 156.

[12] Paridis v Settlement Agents Supervisory Board [2007] WASCA 97; (2007) 33 WAR 361 [53].

[13] Waite v Alcoa of Australia Ltd [2020] WASCA 1 [107].

[14] Bowles v Department of Justice [2005] WASCA 28 [31].

[15] Panegyres v Medical Board of Australia [2020] WASCA 58 [322].

[16] Engine Protection Equipment Pty Ltd v Miller [2018] WASCA 55 [46].

[17] Dodson v Woolworths Group Ltd [2022] WASCA 22 [76].

[18] Mineralogy Pty Ltd v Citic Limited [2024] WASCA 168 [56].

[19] River Hill Contracting Pty Ltd v Moore [2023] WASCA 111 [1].

[20] Summit Homes v Lucev (1996) 16 WAR 566, 569.

[21] SZBEL v Minister for Immigration and Multicultural and Indigenous Affairs [2006] HCA 63; (2006) 228 CLR 152 (SZBEL) [25].

[22] Kioa v West [1985] HCA 81; (1985) 159 CLR 550, 585.

[23] Re Minister for Immigration and Multicultural and Indigenous Affairs; Ex parte Lam [2003] HCA 6; (2003) 214 CLR 1 [37].

[24] HT v The Queen [2019] HCA 40; (2019) 269 CLR 403 [18].

[25] Re Refugee Review Tribunal; Ex parte Aala [2000] HCA 57; (2000) 204 CLR 82 (Ex parte Aala) [101]. This proposition is derived from the judgment of McHugh J in Ex parte Aala. McHugh J was in dissent in Ex parte Aala. His Honour differed in the ultimate outcome based on discretionary grounds. However, there is no doubt as to the correctness of McHugh J's statement of principle. Also, while the statement was made in the context of administrative decision-making, it is equally applicable to curial or quasi-curial decisions.

[26] Assistant Commissioner Condon v Pompano Pty Ltd [2013] HCA 7; (2013) 252 CLR 38 [156].

[27] Stead v State Government Insurance Commission [1986] HCA 54; (1986) 161 CLR 141, 145, 147.

[28] Nobarani v Mariconte [2018] HCA 36; (2018) 265 CLR 236 [38] ‑ [39].

[29] Commissioner for ACT Revenue v Alphaone Pty Ltd [1994] FCA 1074; (1994) 49 FCR 576, 590 ‑ 592.

[30] Apache Northwest Pty Ltd v Agostini [No 2] [2009] WASCA 231 [217] ‑ [218].

[31] McKay v Commissioner of Main Roads [2013] WASCA 135 [156].

[32] Davie v Manuel [2024] WASCA 21 [89] (and see more generally at [87] - [91]).

[33] F Hoffmann-La Roche & Co AG v Secretary of State for Trade and Industry [1975] AC 295, 369.

[34] Victims Compensation Fund Corporation v Nguyen [2001] NSWCA 264; (2001) 52 NSWLR 213 [40].

[41] Tabloid Pty Ltd v Pringle [2024] WASCA 152 [66] ‑ [72].

[42] Kipoi Holdings Mauritius Ltd v Kirman [No 4] [2024] WASCA 145 [486] ‑ [500] (see also [510] ‑ [513], [527] ‑ [529], [534]).

[43] Browne v Browne [2019] WASCA 1 [80].

[44] Wainohu v New South Wales [2011] HCA 24; (2011) 243 CLR 181 [56].

[45] DL v The Queen [2018] HCA 26; (2018) 266 CLR 1 [32].

[46] Child and Adolescent Health Service v Mabior [2019] WASCA 151; (2019) 55 WAR 208 [100].

[47] Velez Pty Ltd v Tudor [2011] WASCA 218.

[48] Sotico Pty Ltd v Wilson [2007] WASCA 112 [23] ‑ [24].

[49] Manonai v Burns [2011] WASCA 165 [56].

[50] Duluxgroup (Australia) Pty Ltd v Chapple [2023] WASCA 83 [20], [49] ‑ [52].