SAS TRUSTEE CORPORATION v PEARCE

Where on a statutory appeal a decision of the Court below in point of law is said to be erroneous, a ground alleging failure to give reasons must be identified as a decision in point of law. The reasons given by the trial judge were adequate: [121]. Pettitt v Dunkley [1971] 1 NSWLR 376; Soulemezis v Dudley (Holdings) Pty Ltd (1987) 10 NSWLR 247, considered.

Director-General, Department of Aging, Disability and Home Care v Lambert [2009] NSWCA 102; referred to. IN THE SUPREME COURT OF NEW SOUTH WALES COURT OF APPEAL CA 40383/08 DC RJ 00616/07

BEAZLEY JA GILES JA BASTEN JA

24 September 2009 SAS TRUSTEE CORPORATION v Anthony Raymond PEARCE Judgment 1 BEAZLEY JA: I agree with Basten JA. 2 GILES JA: The Police Regulation (Superannuation) Act 1906 ("the Act") provides by s 12D that the appellant may pay to a former member of the police force who was hurt on duty a "gratuity" not exceeding the amount that would have been payable had the member been a worker for the purposes of the Workers Compensation Act 1987 ("the WC Act"). "Hurt on duty" is defined to mean "injured in such circumstances as would, if the member were a worker within the meaning of [the WC Act], entitle the member to compensation under that Act". 3 The respondent was a member of the police force from 1982. In the course of his duties he was exposed to a number of traumatic or stressful events. He went on sick leave in February 2005 and was discharged on medical grounds in September 2006. He applied to the appellant for payment of a gratuity on the basis of a constellation of injuries, including psychological injury. 4 By the time the respondent's application was considered by the appellant -

(a) it had been certified by the appellant pursuant to s 10B(1) of the Act that he was incapable of personally exercising the functions of a police officer from "infirmities" which included "chronic/severe post-traumatic stress disorder" and "chronic/moderate major depression"; and

(b) it had been decided by the Commissioner of Police pursuant to s 10B(3) of the Act that the infirmities were caused by him being hurt on duty, and as to the psychological injury that the date on which he was hurt on duty was "10 November 2005 (PTSD notional)". 5 The Commissioner's decision referred only to PTSD, but may be taken to have included the depression. 6 Lump sum compensation for psychological injury was available under the WC Act from 1 January 2002, when amendments made by the Workers Compensation Legislation Amendment Act 2001 and the Workers Compensation Legislation Further Amendment Act 2001 came into force. Lump sum compensation became payable for psychological injury pursuant to ss 66 and 67 of the WC Act according to the resulting degree of permanent impairment, provided the psychological injury was not secondary to physical injury and the degree of permanent impairment was at least 15 per cent (s 65A). 7 However, other provisions of the workers compensation legislation could, speaking generally, exclude compensation for permanent impairment due to psychological injury prior to 1 January 2002. Those provisions were (and are) -

(a) transitional provisions in the Workers Compensation Legislation Further Amendment Act, Schedule 6 Pt 18C, relevantly cl 3(2) and (3) - "(2) There is to be a reduction in the compensation payable under Division 4 of Part 3 (as amended by the Lump Sum Compensation Amendments) for any proportion of the permanent impairment concerned that is a previously non-compensable impairment. This subclause does not limit the operation of section 323 of the 1998 Act or section 68B of the 1987 Act.

(3) Previously non-compensable impairment is loss or impairment that is due to something that occurred before the commencement of the amendments to Division 4 of Part 3 made by the lump sum compensation amendments, being loss or impairment that is of a kind for which no compensation was payable under that Division before that commencement";

(b) s 323 of the Workplace Injury Management and Workers Compensation Act 1998 ("the WIM Act"), relevantly providing - " 323 Deduction for previous injury or pre-existing condition or abnormality

(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." 8 The appellant declined to grant a gratuity in respect of the respondent's psychological injury, in its determination of the amount of the gratuity finding in relation to psychological injury "0% whole person impairment (WPI), as a result of the psychological injuries sustained on the notional date of 10 November 2005". The basis for the determination in this report was not explained, but it is tolerably clear that it was, and was understood to be, that the respondent's psychological injury was attributable to his exposure to traumatic or stressful events prior to 1 January 2002 notwithstanding that he had continued to perform his duties and there had also been exposure after that date. 9 The respondent applied to the District Court pursuant to s 21(1) of the Act, pursuant to which the court could set aside the appellant's determination and make its own determination. He claimed that the appellant's determination be set aside and that it be decided that he "suffered a 17% whole person impairment as a result of his psychological injuries". 10 The appellant said in its defence that the assessment of nil whole person impairment "was in respect of all incidents after 1 January 2002" and "was reasonable, after making the required statutory deductions for impairment caused by psychological injuries prior to 1 January 2002". It said also that any psychological impairment caused by psychological injuries after 1 January 2002 was "less than 15% Whole Person Impairment". 11 Before the trial judge, Hughes DCJ, the respondent contended that his psychological condition was a "disease … of such a nature as to be contracted by a gradual process" within s 15 of the Act; that the injury was deemed to have happened at the time of his incapacity (s 15(1)(a)(i)); that the time of his incapacity was in February 2005 when he went on sick leave from which he did not return; and that his compensation or permanent impairment were therefore not subject to any reduction or deduction. Alternatively, he contended that there was aggravation of a disease within s 16 of the Act, although he did not make clear how the deemed date of injury (s 16(1)(a)(i)) translated to the full 17 per cent impairment. 12 The appellant disputed the application of s 15 of the Act, while accepting that the respondent "has an aggravation argument", and contended that the transitional provisions or s 323 of the WIM Act required deduction to the extent the respondent's permanent impairment resulted from injury prior to 1 January 2002. Even a small deduction, it submitted, would take the permanent impairment below the 15 per cent threshold. 13 Hughes DCJ set aside the appellant's determination and found that the respondent had suffered a 15.3 per cent "whole person impairment" as a result of his psychological injuries. His Honour arrived at that determination by - (i) finding that the respondent's PTSD "cannot be described as a disease of gradual onset but rather a series of frank injuries or shocks";

(ii) holding that s 323 of the WIM Act required a deduction for each of the frank injuries prior to 1 January 2002;

(iii) finding that it was difficult to determine the extent of the deduction;

(v) accepting an assessment of Dr Lambeth of 17 per cent whole person impairment "at the relevant date, that is the last date that the Corporation deemed this disease" [sic]; and

(vi) calculating 17 per cent less 10 per cent of 17 per cent to arrive at 15.3 per cent. 14 His Honour did not in his reasons refer to the transitional provisions. 15 The appeal to this Court is brought pursuant to s 142N of the District Court Act 1973, whereby the appellant can appeal if "aggrieved by an award of the Court in point of law". "Award" is defined in s 142M in the terms, "includes interim award, order, decision, determination, ruling and direction". The factual finding concerning PTSD 16 An essential factual finding was the nature of the infirmities certified by the appellant as PTSD and depression and giving rise to the permanent impairment. There were questions. For the respondent's reliance on s 15 of the Act, was his psychological condition a disease of such a nature as to be contracted by a gradual process? For his reliance on s 16, was there injury by aggravation of PTSD or depression when there was further exposure to traumatic or stressful events? Correspondingly, for the appellant's reliance on the transitional provisions and s 323 of the WIM Act, was there impairment due to traumatic or stressful events prior to 1 January 2002, distinct from the PTSD or depression as at February or November 2005; or was there previous injury or a pre-existing condition to which the impairment was due, distinct from that PTSD or depression? 17 As I have said, the trial judge found that PTSD was not a disease of gradual onset but a series of frank events or shocks. The finding was apparently in response to the respondent's reliance on s 15 of the Act, and was then taken up for the purposes of s 323 by the observations that s 323(1) "allows the earlier incidents to be counted" and that "it was not argued by [the appellant] that such a deduction, that is ten per cent, for the series of frank injuries before, should not be counted". The finding was then the basis for it being too difficult or costly to arrive at a deduction and hence the assumed 10 per cent deduction. 18 In making the finding the trial judge first posed whether PTSD was a disease of gradual onset or a series of frank events or shocks, and then answered the question as follows (the introductory word "Further" was inappropriate, as there was nothing to which the answer was relevantly "further") - "Further, when analysing Post Traumatic Stress Disorder, I went to the Macquarie dictionary and looked at the word, 'trauma'. 'Trauma' is defined in the Macquarie dictionary, and I might say helpfully it gives a subsidiary definition that is applied to psychology, 'A startling experience which has a lasting effect on mental life. A shock.' The word 'post', means after and 'trauma', means a shock; therefore 'post-traumatic' means after a shock, resulting in a shock, causing stress. It seems to me clear that to characterise a series of frank injuries as a disease of gradual onset is a misnomer and I so find that the post-traumatic stress disorder that Mr Pearce suffered cannot be described as a disease of gradual onset but rather a series of frank injuries or shocks." 19 Assuming that the question was an appropriate way of enquiring into the nature of the certified infirmities - which I doubt - the combination of the word "post" with the dictionary definition of "trauma" was an entirely illicit means of arriving at the nature of PTSD; I pass over the failure to address depression at all. The nature of the infirmities was a matter of medical expertise and for expert evidence. There was some medical evidence, albeit not particularly directed to the questions to which I have referred or the question posed by the trial judge, on which the questions could have been addressed. The trial judge did not act upon the evidence at all, but on what he perceived to be the combined meaning of two ordinary words. 20 Putting aside any complaint available to the respondent, in my opinion the trial judge thereby erred in law in a way fundamental to his application of s 323 of the WIM Act. Making a factual finding in the absence of any evidence or when the evidence is incapable of supporting the finding is error of law (Azzopardi v Tasman UEB Industries Ltd (1985) 4 NSWLR 139 at 155; State of New South Wales v Allen [2000] NSWCA 141 at [107]; Seltsam Pty Ltd v Ghaleb [2005] NSWCA 208 at [158]; Haider v J P Morgan Holdings Aust Ltd [2007] NSWCA 158 at [33]; Ormwave Pty Ltd v Smith [2007] NSWCA 210 at [12]-[16]; Amaca Pty Ltd v A B & P Pty Ltd [2007] NSWCA 220; (2007) Aust Torts Rep 81-910 at [134]; and many other cases). A finding made not on the evidence, and where the question is one for medical expertise on a basis other than medical expertise, is in the same position. There was not even fact-finding "marred … by patent error, illogicality or perversity" (Azzopardi v Tasman UEB Industries Ltd at 156-7 per Glass JA). The evidence was ignored, and the reasoning from combining lay meanings of the two words to the nature of PTSD was not available. 21 The notion of grievance with a determination in point of law may go further, but for this reason the appellant has established grievance with the trial judge's determination in point of law. The 10 per cent deduction 22 The trial judge said simply, by "those events" meaning what he regarded as the series of frank injuries - "And I find it is difficult to determine each one of those events that are detailed in Ms Kilpatrick's report, and they may not even be the limit of events, what part each of those events played and, therefore, I accept the recommendations of the legislations [sic] and accept a 10% deduction." 23 As part of s 323(2), an assumed deduction of 10 per cent of the impairment could not be made if the assumption was "at odds with the available evidence". 24 Dr Lambeth considered that an event in 1988 "was the initiating event with respect to his Post Traumatic Stress Disorder", and that subsequent events had "caused exacerbation such as to cause his current incapacity"; he said that the respondent's "disorder is long-standing". Dr Gertler said that the 1988 event was the cardinal event, that the majority of events which thereafter occurred did so before 1 January 2002, and "[a]s such, the proportion of WPI which can be attributed to events prior to 1 January 2002 would be almost 100%". Dr Spruce said that the respondent's presentation was "consistent … with an exacerbation of a Post Traumatic Stress Disorder arising from the original shooting in 1988". The report of Dr Anderson was not specific, but said that the respondent had been re-experiencing the traumatic events for a long time. 25 The trial judge's reasons included recitation of s 323(2), but his Honour did not expressly refer to whether assuming a 10 per cent deduction was at odds with the available evidence. The recitation of s 323(2) was followed by the observation that the appellant had not argued that a ten per cent deduction should not "be counted". This is unclear. The appellant had certainly not conceded that the assumed deduction was appropriate, and its case was that the evidence called for complete or major reduction or deduction. 26 It may be that the trial judge did not turn his mind to whether the assumption was at odds with the available evidence. I think that is likely, although the unsatisfactory reasons make it difficult to draw inferences from what was or was not dealt with; it was an important matter which required express reference, and absence of reference suggests that it was overlooked. If so, there was error of law in failure to apply the law. Alternatively, on the trial judge's approach - which for the reasons I have given was unsound - the medical evidence was such that it was not open to him to find, if he did, that the assumption was not at odds with the available evidence. 27 In this respect also, in my opinion, the appellant has established grievance with the trial judge's determination in point of law. The result 28 This Court can not make factual findings material to the availability of s 15 or s 16 of the Act; see most recently Caltex Refineries (Qld) Pty Ltd v Stavar [2009] NSWCA 258 at [12] per Allsop P, Simpson J agreeing, and cases there cited. The Court's confined power was not in contest. 29 The transitional provisions could apply if a proportion of the respondent's impairment was "a previously non-compensable impairment"; that is, impairment from psychological injury due to the traumatic or stressful events that occurred prior to 1 January 2002. 30 A traumatic or stressful event or events may not immediately bring psychological injury. Impairment is not necessarily the same as having psychological injury or a psychological condition - apart from about 8 days, the respondent carried out his policing duties until he went on sick leave in February 2005. This Court can not make factual findings concerning the divisibility of the respondent's impairment into a previous impairment and a subsequent impairment and the contributions of traumatic and stressful events over the years. 31 Basten JA, whose reasons I have had the advantage of reading in draft, considers that s 323 of the Act does not apply, because on its correct construction the Commissioner's decision established injury deemed to have happened on 10 November 2005 in the application of s 15 or s 16 of the Act. I respectfully take a different view. 32 The Commissioner decided that the date on which the respondent was hurt on duty (which must relevantly mean the date on which he suffered psychological injury) was 10 November 2005, but described the date as notional. The parties disagreed on the consequences of this description. 33 The Commissioner was required by s 10B(3) of the Act to decide "the date or dates on which the member … was hurt on duty". In my opinion, unless it was intended to state a deemed date he did not do so: a notional date is not a true date on which injury is suffered. I do not understand the decision to state a deemed date, first because the word is "notional" not "deemed" and secondly because the date 10 November 2005 was not on the evidence the time of the respondent's incapacity (or the time he made a claim for compensation). In an application to the District Court under s 21(1)(a) of the Act it is open in my view to contend that a purported decision made by the Commissioner is not effective, and in my opinion the description of the date as notional had the consequence that there was not an effective decision of the date on which the respondent suffered psychological injury. 34 Thus s 323 of the WIM Act may also apply, although there is a question, raised in the appeal but not fully debated, whether it applies only in assessments made under the scheme for assessments in the WIM Act and not (even by importation) in a determination under the Act. Subject that question, it could apply if a proportion of the respondent's impairment resulting from his psychological injury was "due to … any previous injury … [or] any pre-existing condition … ". Again, this Court can not make factual findings concerning previous psychological injury or psychological condition and any proportion of the respondent's impairment due to it. 35 There must therefore be remission to the District Court for fresh determination. There may be a further question, whether a Commissioner's decision as to the date on which a member of the police force was hurt on duty is a prerequisite to a determination by the appellant to pay a gratuity. If so, and if it be correct that there was not an effective decision of the date on which the respondent suffered psychological injury, it may be that the application to the District Court cannot be concluded until an effective decision has been made. This was not the subject of submissions. 36 I propose the orders -

(3) Remit the proceedings to the District Court for fresh determination.

(4) Costs of the first trial to be in the disposal of the judge making the fresh determination.

(5) Respondent to pay the appellant's costs of the appeal and to have a certificate under the Suitors Fund Act if otherwise qualified. 37 BASTEN JA: Since 1 January 2002 lump sum compensation payments have been available to injured workers under the Workers Compensation Act 1987 (NSW) for non-economic loss, including loss resulting from psychological injury, where the injury results in a level of "permanent impairment": Pt 3, Div 4. A member of the police force who is "hurt on duty" may claim such a payment as a "gratuity" not exceeding the amount which would have been payable had the officer been a worker for the purposes of the Workers Compensation Act: Police Regulation (Superannuation) Act 1906 (NSW) ("the Police Superannuation Act"), s 12D. 38 On 8 September 2006, Senior Constable Anthony Raymond Pearce (the respondent) was discharged on medical grounds from the NSW Police Force. He sought from the appellant (referred to in the Police Superannuation Act and hereunder as the "STC") a "gratuity" in accordance with s 12D(3) of the Police Superannuation Act. By a decision notified to the respondent on 27 September 2007, the STC declined to grant the gratuity sought. It did so on the basis, at least implicitly, that his psychological injuries were sustained before 1 January 2002. 39 On 18 December 2007 the respondent commenced proceedings in the District Court seeking a determination that he had suffered "a 17% whole person impairment as a result of his psychological injuries". On 12 August 2008, the District Court (Hughes DCJ) found that the respondent suffered from "a whole body impairment of 15.3% as a result of psychological injuries". The Court reached that figure by attributing 10% of the total impairment to psychological injuries received before 1 January 2002. The STC seeks to appeal from that determination. Scope and nature of appeal 40 The jurisdiction of the District Court invoked by the respondent is described as "residual jurisdiction" and was conferred on the Court by the Compensation Court Repeal Act 2002 (NSW). Relevantly for present purposes, it was engaged by the respondent as a person who considered himself aggrieved by "a decision made by STC on a matter that arises under [the Police Superannuation Act] by reason of a member of the police force being hurt on duty": Police Superannuation Act, s 21(1)(a). The power conferred on the District Court was either to confirm the decision of the STC or set aside the decision and replace it with a different decision: s 21(4). The District Court could only make a decision which the STC could have made and the Court's decision is deemed to be a decision of the STC: s 21(5) and (6). The Court had limited powers to award costs: s 21(8)-(10). 41 In exercising its powers in the residual jurisdiction, the Court is required to make a decision "on the real merits and justice of the case" and is not bound to follow "strict legal precedent": District Court Act 1973 (NSW), s 142J(1)(a) and (b). A decision of the Court is protected by a privative clause which purports to preclude review of the Court's decision otherwise than by way of a statutory appeal under s 142N: see s 142J(1)(c). The right of statutory appeal, invoked by the STC in the present case, is available to "a party to any proceedings before the Court in its residual jurisdiction" which is aggrieved by "an award of the Court in point of law": s 142N(1). The term "award" is defined to include "interim award, order, decision, determination, ruling and distinction": s 142M(1). 42 The STC was joined as defendant to the proceedings commenced in the District Court. The appropriateness of that course was not in issue in the present appeal, nor was any question raised as to the right of the STC to appeal to this Court under s 142N. Perhaps curiously for a person properly joined as a party in the District Court, the STC is expressly given a right to be represented at a hearing in the District Court: Police Superannuation Act, s 21(3). Issues 43 The first ground of appeal relied on by the STC was a failure on the part of the District Court judge to give "adequate reasons" for his decision. This was dealt with as the primary ground in argument before this Court. Whether such a ground was properly open was not directly addressed. However, given that the subject matter of an appeal under s 142N is in effect a decision of the District Court in point of law, it is at least open to doubt as to whether the ground relied upon involved a challenge to any such decision, explicit or implicit: see Day v SAS Trustee Corporation [2009] NSWCA 222. Furthermore, it may be doubted whether his Honour in fact failed to give reasons for findings which he made, as opposed to failing to consider certain matters which may have been material, in point of law. The ground is not made good: see [117]-[121] below. 44 The second ground of appeal alleged a failure "to properly construe and apply s 323 of the Workplace Injury Management Act", being a reference to that provision in the Workplace Injury Management and Workers Compensation Act 1998 (NSW) ("the Workplace Injury Act"). That provision required a deduction from an assessment of permanent impairment for any proportion of the impairment due to a previous injury. Where the deduction could not readily be assessed, the statute permitted, subject to a qualification, a 10% deduction to be assumed. The STC said that the section was applicable, but that the evidence justified a far higher deduction which meant the 10% rule could not apply. The respondent by way of his notice of contention stated that s 323 was inapplicable. One consequence of that approach may have been that his Honour was in error in reducing the degree of permanent impairment from 17% to 15.3%. Nevertheless, the respondent did not seek to cross-appeal, but merely to uphold the assessment in the District Court. The respondent's contention should be accepted. 45 The third ground of appeal complained of a failure to address the submissions by the STC regarding the appropriate discount to be applied pursuant to s 323 of the Workplace Injury Act. That ground may have been characterized as a form of procedural unfairness, although it is not immediately clear that such a ground would fall within the terms of the statutory right of appeal. The substance of the ground will, in any event, be considered below in discussing the operation and application of s 323. 46 Ground 4 concerned the failure of the trial judge to address the evidence of Dr Gertler, with respect to the appropriate apportionment of permanent impairment as a result of events which occurred before 1 January 2002. That ground could have required attention to the transitional provisions with respect to the amendments permitting lump sum compensation payments for psychological injury, which commenced on 1 January 2002. The evidence was the subject-matter of the submissions relied on under ground 3, and was thus directed to the operation of s 323. 47 Finally, the respondent contended that the decision of the primary judge should be upheld on a separate basis, namely that the psychological injury which he suffered in the course of his employment was a "disease" for the purposes of the Workers Compensation Act and that it was deemed to have arisen on 10 November 2005, pursuant to s 15(1) of the Workers Compensation Act. That submission raised a further procedural difficulty, namely that it sought to uphold a decision which was otherwise erroneous in point of law by relying upon a finding which, at best, was a mixed finding of fact and law and was not made by the trial judge. Where the jurisdiction of this Court is limited by statute to a decision of the District Court in point of law, it may be that this Court should not grant relief if it is satisfied that the error of law was not material to the ultimate determination made in the District Court. However, it is difficult to see how this Court could uphold the decision of the District Court on the basis of a finding of fact (or fact and law) which was not made by the District Court and was not the only finding open, had that Court addressed the question. Although the contention cannot be determinative of the appeal, it will be necessary to say something about the point of statutory construction on which it was based, in order to understand the scheme of the legislation. 48 In the course of oral submissions in this Court, counsel for the STC relied upon the operation of cl 3(2) of the transitional provisions in relation to amendments to the Workers Compensation Act made in 2001, including the definition in sub-cl (3). The reduction provided by sub-cl (2) required an assessment of "any proportion" of the permanent impairment which was "due to something that occurred" before the commencement of the amendments. Counsel for the respondent somewhat plaintively remarked (Appeal Tcpt, 25/06/09, p 24), "I don't suppose it would assist me to make the observation that the transitional provisions didn't form any part of the grounds of appeal in this case". Whilst that statement was true, the oral argument embraced the transitional provisions and, subject to a question as to costs, there was no contention on the part of the respondent that he was unable to deal with the arguments or was otherwise prejudiced by the matter being raised in an informal manner. The operation of the transitional provisions had been the subject of debate in the District Court. For the reasons explained below, the transitional provisions were material and should have been addressed by his Honour in resolving the extent to which the assessment of permanent impairment should have been reduced because of events causing impairment which had happened prior to 1 January 2002. Factual background 49 The subject-matter of the appeal being limited to a decision of the District Court in point of law, the factual background can be briefly stated. The respondent, having joined the police force in 1982, was exposed to a number of confronting and traumatic experiences over the following two decades. On 28 February 2005 he commenced a period of sick leave, from which he did not return. On 28 October 2005 his solicitors wrote to the STC seeking a medical discharge as a result of work-related psychiatric conditions. They enclosed a report from Dr Leonard Lambeth, a consultant psychiatrist. (Although it does not appear from the evidence, it may be assumed that a similar letter was sent to the Commissioner of Police.) 50 Dr Lambeth, in a report dated 24 October 2005 concluded, without doubt, that the respondent was suffering from "post-traumatic stress disorder - chronic - severe" and "major depression - chronic - moderate": report, p 5. Dr Lambeth further expressed the view that it was "much more probable than not" that his work as a police officer was the substantial contributing factor to his infirmity and that he was to be regarded as "100% totally incapacitated" for work. 51 The history of the respondent's experiences in the police force are helpfully set out in a report dated 25 June 2005, prepared by Dr Kym Kilpatrick, a psychologist. Dr Kilpatrick identified symptoms of stress and trauma as early as 1984, following the respondent's discovery and recovery of two drowned children (report, p 3). The following year he was involved in a cliff rescue at Garie Beach to the south of Sydney when the rotor of a helicopter caused a rock slide from which the respondent received lacerations to the head, whilst attempting to cover the body of the person being rescued. In 1987 the respondent was assaulted by two men in his local pub after being recognised as a police officer. However, the most significant incident occurred on 21 January 1988 when he was attacked by a man with an axe raised in each hand. The respondent fired at the man, causing his death. Two months later there was a further incident involving the capture of an escaped prisoner in bushland. 52 As a member of the dog squad, the respondent was involved in numerous searches for armed and dangerous offenders in the period 1991 to 1996. Dr Kilpatrick referred to three specific incidents of note in 1994. In one case, the respondent was asked to provide support and assistance to a fellow officer who had shot and killed an escaped prisoner in Brisbane. Despite his assistance, the officer shot himself on return to work. In the same year the respondent was fired upon whilst attending a siege at Petersham in Sydney. Further, in June 1994 allegations were made about him at the Wood Royal Commission. Although he was cleared of any impropriety, the experience was clearly stressful. 53 On 21 December 1999 the respondent was asked to assist fellow officers who had been involved in a shooting at Albury and, on 9 January 2000, was involved with another officer in attempting to negotiate the end of a siege involving a woman armed with a knife. During the negotiations, the woman started to cut her arms and sawed under her chin, thrusting the knife into the cavity of her mouth. 54 There were a series of further incidents after 1 January 2002. On 13 September 2003, the respondent was involved in a siege at Glenn Innes, during which an individual poured a large volume of petrol into the body of his car whilst parked next to bowsers at a petrol station. He sat in the car all night with a lighter in his hand, igniting the car at 8am the following morning. The respondent was involved in removing the burning body from the car in an unsuccessful attempt to save the man's life. 55 On 4 February 2004 the respondent with a group of officers approached a large marijuana crop at Torrington, the officers being armed only with pistols. Shots were fired by an offender with a rifle who later decamped. In September 2004 he was involved in another siege involving a man barricaded inside a house and threatening to injury himself with an axe. 56 A number of medical reports were tendered at the hearing in the District Court, some of which are not in evidence before this Court. Those which were in evidence included three reports of Dr Lambeth, whose diagnoses have been noted above. Dr Lambeth also made an assessment of "whole person impairment" in accordance with the WorkCover Guidelines for the evaluation of permanent impairment as required by s 322 of the Workplace Injury Act, in a claim for compensation under the Workers Compensation Act. He assessed the respondent's whole person impairment at 17%: report, 24 October 2005. 57 In a further report of 28 March 2006, he expressed the view that "the event of 1998 was the initiating event with respect to his post-traumatic stress disorder". This would appear to have involved a typographical error in respect of the date, as it appears from his earlier report that he was referring to the fatal shooting in 1988. He said that the respondent was "then a vulnerable person and subsequent events … have exacerbated the post-traumatic stress disorder". He sought to answer a question as to whether post-traumatic stress disorder ("PTSD") would resolve and stated: "The immediate symptoms certainly can resolve, but it is my experience that when the patient is placed back in any situation which could have any reminders of the original initiating event, there is a very strong likelihood that the symptoms will again reoccur and be exacerbated." 58 Dr Lambeth further expressed the view that whilst PTSD is a disorder which "does to some extent" go into remission, it should basically be seen as "being controlled rather than a disorder that is cured". 59 The respondent also saw Dr Robert Gertler, at the request of STC. Dr Gertler's report, dated 27 June 2007, described the respondent's medical condition as "consistent with" the earlier diagnosis of chronic post-traumatic stress disorder and major depression: report, p 4. He also agreed that the respondent was incapable of undertaking any work at all. 60 Dr Gertler made an assessment under the WorkCover Guidelines, arriving at a whole person impairment of 15%. (It appears to have been common ground during the proceedings that there was an arithmetical error in that calculation and that the correct calculation would have accorded with Dr Lambeth's.) Dr Gertler was then asked and answered the following questions (report, p 6): "After arriving at your WPI Assessment please indicate what proportion of the WPI, if any, would you ascribe to a. Any pre-existing psychological condition. There is no evidence that Mr Pearce suffered from a psychological condition prior to the onset of the post-traumatic stress disorder and depression. b. The consequential effects of any physical injury. None. c. Any event that occurred before 1 January 2002. The cardinal event was the shooting which took place in 1988. The majority of events which occurred after that time did so before 1 January 2002. As such, the proportion of WPI which can be attributed to events prior to 1 January 2002 would be almost 100%." 61 Other reports in evidence before this Court included a report from Dr Peter Anderson of 4 November 2005 and a report from Dr Frank Spruce of 29 June 2005. Each was a consultant psychiatrist and neither expressed a view significantly inconsistent with those noted above. 62 Various steps were then taken under the Police Superannuation Act, the legal significance of which will be addressed below. The claim process commenced with a document headed "Claim for hurt on duty benefits" lodged by the respondent and dated 2 March 2005. In a supporting letter dated 31 March 2005, the respondent identified numerous occasions on which he had been exposed to "horrific and disturbing incidents", commencing with what he described as the "Original Injury", in January 1988. The response to that claim is not revealed in the papers, but is not presently relevant. 63 On 28 October 2005, the respondent's solicitors wrote to the administrator of the STC seeking payment of a gratuity under s 12D of the Police Superannuation Act. The respondent first sought that payment prior to obtaining an entitlement to an annual superannuation allowance. As a result, the Commissioner of Police issued a certificate under s 12D(4) determining that the injury to which the claim related was caused by the member being hurt on duty. However, before the claim for a gratuity was dealt with by the STC, the respondent became entitled to an annual superannuation allowance. It was common ground between the parties that the decision of the STC was made on the basis that par (a) of sub-s 12D(3) was engaged: see [67] below. 64 On 31 August 2006 the STC certified that the respondent was incapable on the basis of a number of infirmities, including "chronic/severe post-traumatic stress disorder; and chronic/moderate major depression". 65 On 27 September 2006 the Commissioner of Police certified that the respondent's infirmity was caused by him having been hurt on duty and identified dates of injury for each of the particular infirmities. The first item on the list read, "10 November 2005 (PTSD, notional)". The meaning of that certificate remained a live dispute on the appeal. 66 On 27 September 2007 the STC notified the respondent's solicitors of its decision. It granted payments by way of gratuity in respect of a number of injuries, but not for "the psychological injuries sustained on the notional date of 10 November 2005". It was the last decision which gave rise to the appeal to the District Court. Statutory structure (a) Police Superannuation Act 67 A claim for a gratuity in the nature of a lump sum compensation payment under the Workers Compensation Act engaged s 12D of the Police Superannuation Act, the operative part of which stated: " 12D Gratuities to members hurt on duty in respect of loss of limbs, medical expenses etc (1) STC may pay to a member of the police force who is hurt on duty or to a former member of the police force who was hurt on duty when he or she was a member of the police force a gratuity of such amount as STC determines, not exceeding the amount that, in the opinion of STC, would have been payable to the member or former member under Divisions 3, 4 and 5 of Part 3 of the Workers Compensation Act 1987 if the member were, or the former member had been, a worker for the purposes of that Act. … (3) STC shall not grant a gratuity under this section to a member or former member of the police force unless: (a) an annual superannuation allowance is payable to the member or former member under section 10 in respect of an infirmity of body or mind arising out of the same injury to which the claim for the gratuity relates, or (b) where an annual superannuation allowance is not so payable, the injury to which the claim for the gratuity relates is determined, pursuant to subsection (4) or on appeal, to have been caused by the member being hurt on duty or the former member having been hurt on duty when he or she was a member of the police force." 68 Although the allowance is described as "payable … under section 10", that section does not appear to provide for a decision that an allowance is payable in any particular case. However, that is not of present concern; of more direct relevance is the provision made for certification in s 10B: " 10B Medical examination of disabled member and determination of whether hurt on duty (1) An annual superannuation allowance or gratuity must not be granted under section 10 to a member of the police force who is discharged unless STC (having regard to medical advice on the condition and fitness for employment of the member) has certified the member to be incapable, from a specified infirmity of body or mind, of personally exercising the functions of a police officer …. … (3) Where a member or former member of the police force is duly certified under subsection (1) …, the Commissioner of Police shall: (a) decide whether or not the infirmity to which the certificate relates was caused by the member being hurt on duty or the former member having been hurt on duty when he or she was a member of the police force, as the case may be, and the date or dates on which the member or former member was hurt on duty, and (b) give the member or former member written notification of the decision." 69 The Police Superannuation Act involves a division of responsibility for decision-making between the Commissioner of Police and the STC. The power to determine the nature and extent of injury and the compensation payable is conferred on the STC, while questions involving the causal connection between an injury and employment, that is whether the member was "hurt on duty", are assigned to the Commissioner: see Commissioner of Police v Kennedy [2007] NSWCA 328 at [42]. Thus, for a superannuation allowance to be payable under s 10, the STC must have certified that the member was "incapable, from a specified infirmity of body or mind": s 10B(1). It appears that, on 31 August 2006, a delegate of the STC gave a certificate identifying a number of infirmities, including "chronic/severe post-traumatic stress disorder" and "chronic/moderate major depression". (This appears from the certificate given by the Commissioner's delegate for the purposes of s 10B(3)(a), dated 27 September 2006. The STC certificate was not in evidence, but nothing turned on that. There is no doubt that a delegate of the STC had certified the respondent to be incapable and had specified the relevant infirmities.) 70 The Commissioner was required to certify under s 10B(3)(a) not merely that the specified infirmities were caused by the member being hurt on duty, but also the date or dates on which the member was hurt on duty. The Commissioner's decision, as set out in the written notification of 27 September 2006, identified various dates for particular injuries, most of which are irrelevant for present purposes. The critical date in relation to PTSD was identified as 10 November 2005 and was described as "notional". No date was specified in relation to depression, but it was reasonable to assume that, as demonstrated in the psychiatric reports, this was a co-morbidity with PTSD and nothing turned on that omission. 71 Because of the division of responsibility between the Commissioner and the STC, it is necessary to understand what the Commissioner certified and what the STC was required to determine under s 12D(1). That in turn requires an understanding of the inter-relationship of the Police Superannuation Act and the Workers Compensation Act. (b) Workers Compensation Act 72 The term "hurt on duty", used in the Police Superannuation Act, is defined to mean "injured in such circumstances as would, if the member were a worker within the meaning of the Workers Compensation Act 1987, entitle the member to compensation under that Act": Police Superannuation Act, s 1(2), hurt on duty. The Workers Compensation Act does not use the term "injured" but does speak of "injury" and, as will be seen, refers to an injury which has "happened" and an injury which has been "received". The Act defines injury in the following terms in s 4: " 4 Definition of "injury" In this Act: injury: (a) means personal injury arising out of or in the course of employment, (b) includes: (i) a disease which is contracted by a worker in the course of employment and to which the employment was a contributing factor, and (ii) the aggravation, acceleration, exacerbation or deterioration of any disease, where the employment was a contributing factor to the aggravation, acceleration, exacerbation or deterioration …." 73 The references in par (a) to an injury "arising out of" and in par (b), with respect to a disease, to the employment being a contributing factor, are of less relevance than they once were, because s 9A(1) generally (with certain irrelevant exceptions) precludes a payment of compensation in respect of any injury "unless the employment concerned was a substantial contributing factor to the injury". 74 There are other provisions in the Workers Compensation Act which the Commissioner may need to consider in particular circumstances in determining whether an injury would be compensable under that Act. The respondent argued in the present case that either or both of ss 15 and 16 may have been relevant. The operative parts of those sections read as follows: " 15 Diseases of gradual process - employer liable, date of injury etc (1) If an injury is a disease which is of such a nature as to be contracted by a gradual process: (a) the injury shall, for the purposes of this Act, be deemed to have happened: (i) at the time of the worker's death or incapacity, or (ii) if death or incapacity has not resulted from the injury - at the time the worker makes a claim for compensation with respect to the injury, and (b) compensation is payable by the employer who last employed the worker in employment to the nature of which the disease was due. (2) Any employers who, during the 12 months preceding a worker's death or incapacity or the date of the claim (as the case requires), employed the worker in any employment to the nature of which the disease was due shall be liable to make to the employer by whom compensation is payable such contributions as, in default of agreement, may be determined by the Commission. … (4) In this section, a reference to an injury includes a reference to a permanent impairment for which compensation is payable under Division 4 of Part 3. …

16 Aggravation etc of diseases - employer liable, date of injury etc (1) If an injury consists in the aggravation, acceleration, exacerbation or deterioration of a disease: (a) the injury shall, for the purposes of this Act, be deemed to have happened: (i) at the time of the worker's death or incapacity, or (ii) if death or incapacity has not resulted from the injury - at the time the worker makes a claim for compensation with respect to the injury, and (b) compensation is payable by the employer who last employed the worker in employment that was a substantial contributing factor to the aggravation, acceleration, exacerbation or deterioration." 75 Section 16 also contains equivalents to sub-ss (2) and (4) of s 15. Each of these provisions deals with "an injury". There is separate provision in the Workers Compensation Act for apportionment in the case of more than one injury. " 22 Compensation to be apportioned where more than one injury (1) If: (a) the death or incapacity of a worker, or (b) a permanent impairment suffered by a worker as referred to in Division 4 of Part 3 … results from more than one injury to the worker, liability to pay compensation under this Act is to be apportioned in such manner as the Commission determines." 76 The relevant provisions of Pt 3, Div 4, pursuant to which lump sum compensation payments were claimable by the respondent were ss 66 and 67 which, so far as relevant, provided: " 66 Entitlement to compensation for permanent impairment (1) A worker who receives an injury that results in permanent impairment is entitled to receive from the worker's employer compensation for that permanent impairment as provided by this section. Permanent impairment compensation is in addition to any other compensation under this Act. … 67 Compensation for pain and suffering (1) A worker who receives an injury that results in a degree of permanent impairment of 10% or more is entitled to receive from the worker's employer as compensation for pain and suffering resulting from the permanent impairment an amount not exceeding $50,000. Pain and suffering compensation is in addition to any other compensation under this Act." (c) psychological injury: 2001 amendments 77 Pursuant to the 2001 amendments to the workers compensation legislation which commenced on 1 January 2002, such additional payments could be made in relation to psychological injury, so long as it was not secondary to a physical injury. Further, neither compensation for permanent impairment nor for pain and suffering was available in respect of psychological injury "unless the degree of permanent impairment resulting from the primary psychological injury is at least 15%": s 65A(3). 78 Prior to the 2001 amendments, Pt 3, Div 4 contained two provisions relating to multiple injuries, namely ss 68A and 68B. So far as relevant, these provisions stated: " 68A Deduction for previous injury or pre-existing condition or abnormality (1) In determining the compensation payable under this Division for a loss, there is to be a deduction for any proportion of the loss that is due to any previous injury (whether or not it is an injury for which compensation has been paid or is payable under this Division) or that is due to any pre-existing condition or abnormality. … 68B Deductions under section 68A - operation of sections 15, 16, 17 and 22 (1) When determining the compensation payable for a loss for the purposes of the apportionment of liability under s 22, there is to be no deduction under section 68A for any proportion of the loss that is due to an injury in respect of which liability is to be apportioned (but without affecting any deduction under that section for any proportion of the loss that is due to any other injury or that is due to any pre-existing condition or abnormality). (2) When determining the compensation payable in a case in which section 15 applies (disease of such a nature as to be contracted by a gradual process) there is to be no deduction under section 68A for any proportion of the loss that is due to the worker's employment (after the commencement of this Act) by a previous employer in employment to the nature of which the disease was due (but without affecting any deduction under that section for any proportion of the loss that is not due to the worker's employment in employment to the nature of which the disease was due or that is due to any pre-existing condition or abnormality). (3) When determining the compensation payable in a case in which section 16 applies (an injury that consists in the aggravation, acceleration, exacerbation or deterioration of a disease) there is to be no deduction under section 68A for any proportion of the loss that is due to the worker's employment … by a previous employer in employment that was a substantial contributing factor to the aggravation, acceleration, exacerbation or deterioration …." 79 The 2001 amendments removed s 68A into the Workplace Injury Act, where it became s 323. Section 68B remained in substantially the same form as set out above, although the reference to "no deduction under section 68A" was changed to "no deduction under section 323 of the 1998 Act", that being a reference to the Workplace Injury Act. (The term "loss" was replaced by "in respect of permanent impairment".) Section 323 of the Workplace Injury Act appears in Pt 7, Ch 7, dealing with assessment of the degree of permanent impairment of an injured worker. The change in the scheme of the legislation may not have been consistently reflected in the language of s 323. The provisions equivalent to the repealed sub-ss (1) and (6) of s 68A now read: " 323 Deduction for previous injury or pre-existing condition or abnormality (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. Note. So if the degree of permanent impairment is assessed as 30% and subsection (2) operates to require a 10% reduction in that impairment to be assumed, the degree of permanent impairment is reduced from 30% to 27% (a reduction of 10%)." 80 As a theoretical matter, there is some awkwardness in suggesting that the degree of impairment resulting from one injury incorporates a degree of impairment resulting from another previous injury, so that the latter is to be deducted from the former. If there were a separate assessment of each, no reduction would be required. However, the WorkCover Guidelines, pursuant to which assessments of degree of permanent impairment are to be made (s 322(1)) stated, under the heading "pre-existing impairment": "To measure the impairment caused by a work-related injury or incident, the psychiatrist must measure the proportion of [whole person impairment] due to a pre-existing condition. … The injured worker's current level of impairment is then assessed, and the pre-existing impairment level (%) is then subtracted from their current level to obtain the percentage of permanent impairment directly attributable to the work-related injury. If the percentage pre-existing impairment cannot be assessed, 10% of the estimated level of the condition now being assessed is to be deducted." 81 It is not necessary for present purposes to consider whether the exercise required by the WorkCover Guidelines is consistent with that required by s 323(1). 82 The history of the 2001 amendments in relation to s 68A of the Workers Compensation Act has bearing on an issue before the District Court, namely whether it was appropriate to apply s 323, and in particular the presumed 10% deduction for impairment due to a previous injury, given that the provision is now to be found in a procedural part of the Workplace Injury Act, which may not generally govern the decision-making process by the STC or, on appeal, the District Court under the Police Superannuation Act. (d) transitional provisions 83 The final (and arguably critical) set of provisions in the workers compensation legislation concerned the transitional provisions consequent on the enactment of the 2001 amendments. Those are to be found in Pt 18C of Sch 6 of the Workers Compensation Act. Prior to the amendments, Pt 3, Div 4 of the Workers Compensation Act included a table which identified specific injuries and specified a percentage of the maximum amount payable in respect of each such injury. The injuries were all physical, none being psychological. In conformity with that approach, s 66, prior to the 2001 amendments, referred to a worker who had suffered "the loss of a thing mentioned in the Table to this Division as the result of an injury" and s 67 referred to "a loss mentioned in the Table to this Division". The new language, referring to "an injury that results in permanent impairment" (in each of ss 66 and 67), permitted claims for lump sum compensation in a range of circumstances in which such claims had not previously been available. These circumstances included, but were not limited to, psychological injury. In this situation, it was clearly necessary to indicate how the amendments applied in relation to injuries and impairments which may have pre-dated the amendments. The primary transitional provision stated that the amendments "do not apply in respect of an injury received before the commencement of the amendments (even if the injury is the subject of a claim made after the commencement of the amendments)": Sch 6, Pt 18C, cl 3(1). As the relevant injury must precede the permanent impairment, it followed that the amendments did not apply in relation to impairments which arose prior to the commencement of the amendments. 84 For present purposes, the critical transitional provisions were to be found in sub-cll (2) and (3) of cl 3, which read as follows: "(2) There is to be a reduction in the compensation payable under Division 4 of Part 3 (as amended by the lump sum compensation amendments) for any proportion of the permanent impairment concerned that is a previously non-compensable impairment. This subclause does not limit the operation of section 323 of the 1998 Act or section 68B of the 1987 Act. (3) A previously non-compensable impairment is loss or impairment that is due to something that occurred before the commencement of the amendments to Division 4 of Part 3 made by the lump sum compensation amendments, being loss or impairment that is of a kind for which no compensation was payable under that Division before that commencement." 85 These provisions potentially gave rise to three questions in the present case, namely:

(a) when was the injury "received" for the purposes of cl 3(1); (b) is the loss or impairment "due to something" occurring before 1 January 2002, and (c) if yes to (b), what proportion of the impairment is due to that thing (cl 3(2))? Reasoning of trial judge 86 After referring briefly to the respondent's history in the police force, and the resultant PTSD, his Honour identified the "essential argument between the parties" (Judgment, p 2) in the following terms: "The argument then was whether or not one could characterise these events as a disease of gradual onset, the PTSD, or was it a series of frank events, to use the old workers' compensation terminology, that was accelerated by these event[s]." 87 His Honour determined that PTSD could not be described as a disease of gradual onset, "but rather a series of frank injuries or shocks". In reaching this conclusion, his Honour noted the certification by the Commissioner of Police, but made no reference to the legal significance of the date specified by the Commissioner nor the possible meaning of the Commissioner's characterisation of the date as "notional". At the conclusion of his reasons, in adopting the assessment of Dr Lambeth, he referred to "the last date that the Corporation deemed this disease": Judgment, p 4. (The reference to "Corporation" probably should have been to "Commissioner".) It is possible that the comparison between a disease and injuries or shocks may not have been intended as a rejection of the identification of PTSD as a "disease", but merely a rejection of it being a disease of gradual onset. 88 His Honour then turned to s 323 of the Workplace Injury Act and concluded that it required a deduction for each of the frank injuries which occurred prior to 1 January 2002. His Honour held that it was "difficult to determine" how those events had operated on the respondent and therefore was required to "accept a 10% deduction": Judgment, p 3. 89 His Honour referred to the reports of Dr Lambeth and Dr Gertler, in order to assess the degree of permanent impairment. He noted that Dr Lambeth had assessed a 17% whole person impairment and Dr Gertler 15%. He noted the acceptance by the parties that there was an arithmetical error in Dr Gertler's assessment and accepted the figure proposed by Dr Lambeth. Deducting 10% of that figure left an impairment of 15.3%. 90 There appeared to have been agreement between the parties that they would be able to work out the relevant figures on the basis of that assessment. The only orders made were to uphold the appeal, set aside the decision of the respondent and record a finding that the respondent "suffers from a whole body impairment of 15.3% as a result of psychological injuries": Order 3. 91 Arguably the "award" was an interlocutory decision, requiring leave of this Court. Neither party so contended and it is convenient to approach the matter on the basis that leave is not required. If leave were required, it should be granted. The issues of statutory construction are of some complexity and may have significance beyond the confines of this case. Further, his Honour's reasons were arguably inadequate in a number of respects. Resolution of appeal (a) the Commissioner's certificate 92 Chronologically, it is convenient to consider first the correct construction of the certificate given by the Commissioner under the Police Superannuation Act. The difficulties in this regard flow in part from the division of functions between the Commissioner of Police and the STC, but also from the need to construe the Police Superannuation Act with the provisions of the Workers Compensation Act and the Workplace Injury Act, in circumstances where the language used is not consistent. Thus, s 10B refers to a person being "incapable", the incapacity arising from a specified "infirmity of body or mind", and the infirmity in turn being caused by the member being "hurt on duty". It is clear that the psychological infirmity was the chronic post-traumatic stress disorder and major depression (the combination being conveniently referred to simply as "PTSD"). The PTSD must thus have been the "injury" which would have entitled the respondent to compensation under the Workers Compensation Act. The requirement that the Commissioner determine the date or dates on which the injury occurred was related to the calculation of the superannuation allowance. (The date appears not to be directly relevant for the purpose of granting a gratuity, because the decision required of the Commissioner under s 12D(4), where s 10 was inapplicable, did not involve the specification of the date or dates on which the injury occurred.) The question which arises in respect of the Commissioner's certificate was the significance of the specification of 10 November 2005 as the relevant date, but one described as "notional". 93 The choice of date was not readily explicable on the evidence. However, it was a date after the respondent had gone on extended sick leave and after medical opinions had been received by the Commissioner indicating that the respondent was wholly incapable of work. (Dr Lambeth's report was received by the STC, and presumably the Commissioner, on 2 November 2005.) 94 The respondent argued that the finding of a notional date in November 2005 was explicable on the basis that the Commissioner had treated the injury as a disease within the terms of ss 15 or 16 of the Workers Compensation Act, with the result that the injury was deemed to have happened at the time of the respondent's incapacity. It would follow, in accordance with ss 15(4) and 16(3) that the permanent impairment was deemed to have happened at the time of his incapacity. 95 This argument gave rise to a number of questions, namely:

(a) did the Commissioner identify the date of injury on the basis of the injury being a disease within s 15 or s 16 of the Workers Compensation Act ? (b) if so, was that finding binding on the STC? (c) did either or both of these questions constitute a point of law? (d) did the District Court make a decision with respect to either or both of these questions?

For the respondent to succeed in its submission on this point, it needed an affirmative answer to each of those questions. A further question would then arise as to the consequence of such a conclusion in relation to the appeal, there being no cross-appeal by the respondent. 96 In my view, the respondent should succeed on each of these specific questions. Despite the logic of the order in which the questions have been posed, it is convenient to consider (b) before (a). That is because an understanding of the functions of the Commissioner may inform a finding as to what he did in exercise of his statutory functions. First, although there are authorities which refer to the Commissioner's certificate as "binding", that language is apt to mislead. The underlying question is whether the STC has power to determine a particular issue arising under the legislation, or whether that particular function is vested in the Commissioner. In respect of the classification of an injury, the answer is not self-evident. In its terms, the Police Superannuation Act does not vest that particular function in either authority. The respondent's argument must be that, because the determination of the date of injury is a function of the Commissioner, any issues necessarily requiring determination in the exercise of that function must be vested in the Commissioner. Because the date of injury is a matter to be determined in accordance with the Workers Compensation Act, it is therefore necessary for the Commissioner to decide whether or not the injury is a disease contracted by a gradual process, or consists in the aggravation, acceleration, exacerbation or deterioration of a disease. If the former, the Commissioner is required to determine the date by reference to s 15 of the Workers Compensation Act, if the latter by reference to s 16. Because the Commissioner cannot make the determination without considering whether the injury falls within either of those provisions, it follows that the determination of that issue falls within the Commissioner's statutory functions. 97 It might in some circumstances be possible that both authorities could have power to determine the same underlying question. However, for the STC (and on appeal the District Court) to determine that the injury was not a disease would be likely to render the Commissioner's certification of the relevant date of injury erroneous. That conclusion would be inconsistent with the statutory scheme and should not be adopted. It follows that, subject to consideration of question (a), his Honour was in error in seeking to determine whether the psychological injury was or was not a disease. 98 Question (a) concerns the proper construction of the certificate. Whether the Commissioner did decide the date of injury by application of s 15 or s 16, thus treating the injury as a disease, depends on the correct understanding of the date chosen and the use of the term "notional". 99 In one sense, the date chosen appears to be arbitrary. There is no evidence in the materials before this Court which would allow an understanding of the significance of the date. Both ss 15 and 16 of the Workers Compensation Act distinguish between an injury which results in incapacity and one which does not. In the former case, the date of injury is deemed to be the time of incapacity; in the case of the latter, the date is deemed to be the time a claim for compensation is made with respect to the injury. The date identified by the Commissioner does not appear to have been the date of claim, but the date of incapacity was no doubt not a date which could be determined with precision. In any event, it is clear that the date chosen was long after the last of the traumatic incidents which may have had a causal connection with the injury. 100 The second problem is that the Commissioner's use of the word "notional" does not conform to the statutory language in ss 15 and 16. Each of those sections identifies a date on which the injury, for the purposes of the Workers Compensation Act, shall "be deemed to have happened". However, there is no reason to view this semantic difference as significant. To describe the date of injury as "notional" implies that it is not the actual date of injury but is a supposed or assumed date. That is consistent with the language of ss 15 and 16: see Coates v Commissioner for Railways (1960) 78 WN (NSW) 377 at 384 (Kinsella and Collins JJ). Because the Commissioner was required to identify the date of injury under the Police Superannuation Act, but for the purposes of applying the provisions of the Workers Compensation Act, it should be inferred that he did so by applying either s 15 or s 16. It was not open to the STC (or the District Court) to take a different view of that matter. The consequence of these conclusions remains to be considered. 101 In relation to question (c) the proper construction of a certificate having statutory effect is a question of law: no contrary argument was proffered. In relation to question (d), it may be inferred that the primary judge implicitly identified either question (a) or (b) (or both) and answered them erroneously. 102 The second contention raised by the respondent was that his Honour erred in finding that PTSD was not a "disease" within the meaning of ss 4, 15 and 16 of the Workers Compensation Act and, in particular, in failing to find that it was a disease of gradual onset for the purposes of s 15. Because this was not a matter which his Honour was required to determine, this question does not arise. However, if that conclusion were not accepted, it would be appropriate to note that his Honour's approach to the question was legally erroneous. To characterise the disease, his Honour took the label and identified dictionary definitions for each word. Thus, his Honour referred to the definition of "trauma" in the Macquarie Dictionary, identifying as the relevant meaning, "[a] startling experience which has a lasting effect on mental life. A shock." He then identified "post" as meaning "after" and thus "post-traumatic" as meaning "after a shock, resulting in a shock, causing stress". 103 The present case was not concerned with a question of statutory construction, but with the meaning of a term in a certificate given statutory effect. The description "post-traumatic stress disorder" had a technical medical meaning, the application of which depended upon defined criteria to be found in recognised psychiatric texts. That conclusion, if not common knowledge, could be derived from the medical reports which were in evidence in the District Court. (b) application of s 323 of Workplace Injury Act 104 The STC relied on s 323 of the Workplace Injury Act as the primary operative provision, a conclusion said to be reflected in the final sentence of cl 3(2) of the transitional provisions. Because his Honour did not accept that PTSD was a disease, he accepted that there were a number of "injuries", some of which happened prior to 1 January 2002. His error, according to the STC, was to ignore the evidence of Dr Gertler, set out at [60] above, that almost the whole of the impairment could be "attributed to events prior to 1 January 2002". Although Dr Gertler made an arithmetical mistake in the application of the WorkCover Guidelines in calculating the percentage of whole person impairment, that mistake did not affect the opinion relied upon. There was no rational basis, the STC submitted, for rejecting this aspect of Dr Gertler's opinion because of the irrelevant arithmetical mistake. If Dr Gertler's opinion were not rejected but overlooked or treated as irrelevant, that would have been erroneous for the purposes of s 323, as the 10% reduction could not be adopted if it would be "at odds with the available evidence". 105 It was not necessary for the STC to contend that Dr Gertler's view be accepted in full. If the degree of permanent impairment attributable to a pre-2002 injury were only 20%, that would nevertheless reduce the overall figure of 17% to a figure below 15%, thus precluding a lump sum compensation payment for psychological injury under Pt 3, Div 4 of the Workers Compensation Act. 106 Assuming that the permanent impairment resulting from PTSD was the result of a number of injuries, s 323 only operated to the extent that it was necessary to determine the degree of permanent impairment "resulting from an injury". This was not an exercise required in the present case. The STC had already identified an "infirmity" of the mind which rendered the respondent "incapable"; the Commissioner had determined that the specified infirmity was caused by a single compensable injury, for the purposes of the Workers Compensation Act. There was therefore no need to ask whether the impairment was due in part to a pre-existing condition, abnormality or "any previous injury", pursuant to s 323(1), for the purposes of Pt 3, Div 4 of the Workers Compensation Act. The respondent's contention that s 323 was not engaged was thus correct and his Honour was in error in applying s 323(2) to reduce the degree of permanent impairment by 10%. 107 The effect of this reading of s 323 may appear anomalous, in that in the case of a disease involving psychological injury, compensation became available for the psychological effects of conditions of employment which arose prior to the amendments. However, the deeming dates in ss 15 and 16 in relation to diseases can have operation which is both favourable and unfavourable to the worker. Thus they can also give a form of retrospective operation to provisions such as ss 9A and 11A which limit the availability of compensation: see Hallett v Commissioner of Police (2004) 1 DDCR 580 at [41]-[[47] (Walker DCJ). 108 To the extent that s 323 depends upon there being separate injuries, that apparent anomaly may be accepted, because the Parliament adopted language which had a defined meaning under the Workers Compensation Act. In any event, the transitional provisions, which deal not with injuries but impairments due to earlier events, have a different operation, which avoids such an anomaly arising. 109 For these reasons the STC's complaint about the application of s 323 is not to the point. Further, s 323 has a different operation from that of cl 3. The reduction required under sub-cl 3(2) does not depend upon the date of an injury or the impairment in question; rather, it operates by reference to an event or thing that occurred before the commencement of the amendments. Thus, if it could be shown that a "proportion" of the permanent impairment was due to such an event or thing, a reduction in the payment of compensation would be required. (c) application of transitional provisions 110 The next question was whether his Honour was in error in failing to address the transitional provisions in the Workers Compensation Act. If those provisions were applicable, there was an error in law in failing to apply them. By simply ignoring them, in circumstances where their application was raised by the parties, it may be said that his Honour implicitly reached a conclusion that they were inapplicable. That would be a decision on a point of law which may be the subject of a statutory appeal: see Kalokerinos v HIA Insurance Services Pty Ltd [2004] NSWCA 312 at [38]-[58] (Bryson JA); Grygiel v Baine [2005] NSWCA 218 at [29]; Director-General, Department of Ageing, Disability and Home Care v Lambert [2009] NSWCA 102 at [70]. 111 To the extent that the PTSD constituted, or was the consequence of, an injury received before the commencement of the amendments, the lump sum compensation amendments did not apply. However, once the Commissioner determined that the injury happened in 2005 because the PTSD constituted a disease within the terms of s 15 or s 16, it was an injury received after the commencement of the amendments on 1 January 2002. The transitional provisions are then engaged. 112 The reduction required by the transitional provision turns on a causal connection between the impairment and events which occurred before the commencement of the amendments. There may be various circumstances in which an injury is received after a particular date but is "due to something" that occurred before that date. Circumstances which engage ss 15 or 16, providing for deemed dates of injury, could also engage the transitional provision and require a reduction under cl 3(2). They require the assessment of a "proportion" of the impairment which is "due to" events occurring before 2002. (d) challenge to factual finding 113 Although the failure to consider the application of the transitional provisions may have involved a decision in point of law that they were not engaged, the STC also challenged the factual finding made by the District Court in invoking the default reduction provided by s 323(2). His Honour appears to have concluded that the proportion of the impairment attributable to pre-2002 injuries was not established by the evidence. His Honour accepted that it would be "difficult or costly to determine" and, at least implicitly, that the assumption of 10% was not "at odds with the available evidence". If that approach were to stand, it might follow, as a practical matter, that no proportion of the permanent impairment could have been determined for the purposes of sub-cl 3(2). 114 The fate of the appeal might therefore turn upon the STC's challenge to the conclusion that his Honour was unable to determine a proportion of the impairment due to the earlier events or (as he characterised them) frank injuries. Erroneous factual findings can be characterised as involving errors of law in some circumstances. However, it is less easy to characterise erroneous factual findings as resulting from a decision in point of law. 115 In substance grounds 3 and 4 were directed to his Honour's calculation of the proportionate reduction (albeit for the purposes of s 323) and the failure to address the evidence of Dr Gertler concerning the apportionment of the impairment "caused by events" before 1 January 2002 (language which was apt to invoke cl 3). 116 As already noted, there is some difficulty in determining how his Honour approached the factual question, even for the purposes of s 323 of the Workplace Injury Act. On one view he may have discarded the whole of Dr Gertler's report; on another, he simply overlooked the opinion expressed in the final paragraphs of the report; a further possibility is that he found it unhelpful in answering the question. The last approach, if explained in the reasons, might have been supportable. The opinion was that almost the whole of the impairment could be attributed to events which occurred prior to 1 January 2002. What that opinion does not explain is why the impairment (and consequent incapacity) did not arise until March (or November) 2005. There was at least a possibility that Dr Gertler had in mind a different concept of causation than that required by s 323 (as his Honour approached the matter) or cl 3(2), as the matter should have been approached. Because the reasoning provided was sparse, it is impossible to draw any particular inference from the circumstances of the case. It is therefore a possibility that his Honour properly considered all of the evidence and was simply not satisfied as to any particular proportionate reduction, without erroneously making any decision in point of law. (e) failure to give reasons 117 It was perhaps in recognition of this difficulty that the STC presented its primary case in this Court on the basis that there had been a failure to give adequate reasons. 118 It is possible to say of any error of law affecting a judgment under appeal that there has been an implicit decision by the court or tribunal below that it has complied with a law. On that approach, it may be said that his Honour had decided (erroneously) that his reasons constituted adequate reasons and that that was a decision in point of law. To approach the matter on that basis would, however, be inconsistent with the distinction studiously drawn in a long line of cases between statutory provisions permitting an appeal generally with respect to a judgment which is said to be affected by error of law and an appeal limited specifically to a decision of the court or tribunal below on a question of law or point of law: see Lambert (at 110 above) at [57]-[75], and the authorities referred to therein. 119 In Pettitt v Dunkley [1971] 1 NSWLR 376 this Court considered the effect of a failure to give reasons in the context of an earlier form of s 142N (then s 142) which was substantially in the same terms as s 142N. The distinction drawn in the previous paragraph was not drawn by Moffitt JA (with whom Manning JA agreed): at 389. As a result, his Honour referred indiscriminately to the judge failing or declining to give reasons for his decision. Asprey JA, who appears to have been alert to the construction of the section now accepted, stated at 383D-384: "When the learned trial judge delivered his judgment in the form which I have quoted above it will be plainly seen that his Honour made a conscious decision not to deliver reasons or to state the findings of fact which it was necessary for him to have resolved in order to enter the verdict. … It is unnecessary that a party should have requested him to decide a point of law if in fact the judge himself makes the decision. In the present case it cannot be doubted that the learned judge clearly posed the question to himself and decided it as the phraseology of his judgment plainly shows." 120 Other cases concerned with the duty to give reasons, even if arising in relation to statutory provisions equivalent to the present form of s 142N, have been content to discuss the issue in terms of "error of law", without reference to the need to find a decision of the tribunal below in point of law: see, eg, Soulemezis v Dudley (Holdings) Pty Ltd (1987) 10 NSWLR 247. 121 Once it is recognised that it is the decision of the Court below in point of law which is said to be erroneous, it follows that a failure to give reasons must be identified as a decision in point of law. There will be extreme cases where that may be said to arise; Pettitt was one, as explained by Asprey JA. However, this is not such a case. It is clear not only that his Honour decided to give reasons but that he did so. Given the restrained form of appeal in s 142N of the District Court Act, the ground of inadequate reasons is not available in the present case. (f) a material error? 122 Although the challenge to the adequacy of the Court's reasons given by the primary judge does not succeed, and the challenge to the factual finding is therefore difficult to support as a challenge to a decision in point of law, the appeal should nevertheless be upheld. Whatever the precise finding made by his Honour under s 323 of the Workplace Injury Act, that finding concerned the proportion of the impairment "due to any previous injury". That is not the same as a finding as to the proportion of an impairment, due to a previous event. Thus, a finding that the former could not be assessed on the evidence, does not necessarily entail a similar conclusion in relation to a latter test. The point of construction upon which the two provisions were found to have a differential operation identifies the possibility of different factual findings under each provision. The Commissioner had identified the only relevant "injury". Thus, as a matter of law, his Honour should have found there was no "previous injury" for the purposes of s 323. The same conclusion would not necessarily follow in respect of the test under the transitional provision. Accordingly, no relevant finding of fact was made which would render the failure to apply the correct provision immaterial. The critical legal error was the failure to apply the transitional provisions of the Workers Compensation Act, Sch 6, Pt 18C, cl 3(2) and (3). 123 A material difference in the approach adopted by Giles JA lies in his Honour's view that Commissioner's certificate did not identify a date of injury and was to that extent incomplete and invalid. 124 It was appropriate for the District Court to construe the certificate so far as necessary in order to carry out its separate function. If there were no certificate, or it was invalid, the District Court (and indeed the STC) could and should have declined to exercise their powers, because a necessary pre-condition had not been satisfied. However, neither the STC nor the District Court found that a necessary pre-condition to the exercise of their powers had not been fulfilled; neither did either party contend for that conclusion in the District Court. 125 Neither party contended for that result before this Court either. If the STC had done so, it would have been on the basis that its own exercise of power was invalid. The respondent was content to uphold the decision of the District Court. A challenge to the decision of the District Court on a basis not put in issue before it and therefore not decided by it, would have required an application for judicial review under s 69 of the Supreme Court Act 1970 (NSW). No such application was made. 126 Arguably this Court should not reach a firm view as to the invalidity of the Commissioner's certificate, without giving the parties an opportunity to address on that issue. Further, the parties should arguably be given an opportunity to make submissions as to what relief would be appropriate if the Court were of that view. Given the way in which the case was presented, this Court should be slow to reach the conclusion that the certificate was invalid unless satisfied that no other conclusion was reasonably open. As explained above, in my view there is a reasonably available construction of the Commissioner's certificate which avoids invalidity. Once that view is accepted, the difficulties raised by the alternative approach (entailing invalidity) do not arise. 127 Accordingly, the appeal should be allowed and the matter remitted to the District Court, to be determined by application of the correct statutory provision. Costs 128 The STC has succeeded on the basis of the erroneous failure to apply the transitional provisions. Although those provisions were raised before his Honour, the transcript of the argument in the District Court does not demonstrate that their proper operation was presented to his Honour with the degree of clarity which might have achieved a different result. More importantly, they were not relied upon either in the notice of appeal to this Court, nor in the written submissions filed in this Court. As a result, the respondent came to meet an appeal based on grounds on which the appellant has been unsuccessful. In those circumstances, the appellant should not obtain its costs of the appeal. The question is whether it should be ordered to bear the costs of the respondent in this Court. 129 A factor relevant to this question is the role played by the STC. It is (or was) the original decision-maker in relation to the respondent's claim. Once an appeal is brought from its decision to the District Court, the matter is to be determined in that Court and there is no statutory provision for remission back to the STC: Police Superannuation Act, s 21(4). The STC is therefore not constrained by any further decision-making role in its involvement in adversarial litigation in the District Court: cf R v Australian Broadcasting Tribunal; Ex parte Hardiman [1980] HCA 13; 144 CLR 13. Nevertheless, it is not identified as a necessary respondent to an appeal in the District Court. The right of the claimant is to "apply to the District Court for a determination in relation to" the decision of the STC on his or her claim: s 21(1). The STC is given a statutory entitlement to be represented "at the hearing of an application under this section": s 21(3). Nevertheless, the section does envisage that the STC may be a "successful party" in relation to the application for the purposes of a costs order, although the Court "shall not order the payment of costs … by the applicant for a determination under this section unless satisfied that the application was frivolous or vexatious or was made fraudulently or without proper justification": s 21(9). 130 It was not suggested that the STC was not entitled to bring an appeal to this Court, pursuant to s 142N of the District Court Act. However, its role under the Police Superannuation Act is a factor which may properly be taken into account in determining whether or not it should received costs in this Court. 131 The STC, apart from the late reliance on the transitional provisions, has not in any sense behaved improperly, although it has been unsuccessful on most of the issues it sought to raise. Taking all these considerations into account, the appropriate conclusion is that neither party should receive its costs of the proceedings in this Court. Orders 132 I would therefore propose the following orders:

(1) To the extent necessary, grant leave to appeal and dispense with further compliance with the rules.

(2) Allow the appeal and set aside the judgment and orders made in the District Court on 12 August 2008.

(3) Remit the matter to the District Court for redetermination, including in relation to the costs of the first hearing, according to law.

(4) Grant the respondent a certificate under the Suitors' Fund Act 1951 (NSW) in respect of his costs of the appeal. **********

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