FEDERAL COURT OF AUSTRALIA INTERPRETATION OF INSTRUMENTS - "Guide to the assessment of the degree of permanent impairment" prepared pursuant to s 28 the Safety, Rehabilitation and Compensation Act 1988 (Cth) - construction of section of Guide "9 Musculo-skeletal System". INTERPRETATION OF INSTRUMENTS - interpretation of confused language of statutory instrument. Administrative Appeals Tribunal Act 1975 (Cth), s 45 Safety, Rehabilitation and Compensation Act 1988 (Cth), ss 4, 14, 24, 28, 54 Veterans' Entitlements Act 1986 (Cth), ss 24 and 29 Acts Interpretation Act 1901 (Cth), s 15AA Federal Court Rules, O 50 Commission for the Safety, Rehabilitation and Compensation of Commonwealth Employees v Ticsay (1992) 38 FCR 181, applied Comcare v Kay (1997) 26 AAR 124, discussed Scott v Moses (1958) 75 WN(NSW) 101, referred to King Gee Clothing Co Pty Ltd v The Commonwealth (1945) 71 CLR 184, referred to Saraswati v The Queen (1991) 172 CLR 1, followed Mills v Meeking (1990) 169 CLR 214, followed Corporate Affairs Commission (NSW) v Yuill (1991) 172 CLR 319, followed DENNIS JOHN WHITTAKER v COMCARE QG 194 OF 1997 DRUMMOND, COOPER AND FINKELSTEIN JJ 7 SEPTEMBER 1998 BRISBANE IN THE FEDERAL COURT OF AUSTRALIA QUEENSLAND DISTRICT REGISTRY QG 194 of 1997 special case referred by the administrative appeals tribunal BETWEEN: DENNIS JOHN WHITTAKER Applicant AND: COMCARE Respondent JUDGES: DRUMMOND, COOPER AND FINKELSTEIN JJ DATE OF ORDER: 7 September 1998 WHERE MADE: BRISBANE THE COURT DETERMINES THE QUESTIONS OF LAW REFERRED TO IT AS FOLLOWS: Q1. Whether, in the introduction to the musculo-skeletal system tables in the Guide, the expression "soft tissue injury" is qualified by the phrase "not involving joints", so that the indication for the use of Table 9.5, where soft tissue injury to the leg is concerned, is limited to soft tissue injury not involving joints. A: Table 9.5 can be used for the assessment of the degree of permanent impairment resulting from injury to any part of the lower limb, including to any part of a joint. Q2. Whether Table 9.2 is the applicable table in the case of injury to tissues which are integral to the joint. A: Table 9.2 can be used to assess the degree of permanent impairment resulting from injury to a joint in the lower limb irrespective of whether the structures of the joint injured are limited to non-bony elements, but only where the assessment under Table 9.2 results in a higher degree of impairment than would assessment under Table 9.5. Q3. Whether Table 9.5 can only be used in respect of injury to parts of the lower limb other than joints. A: No Q4. If both Table 9.2 and Table 9.5 are capable of being used for the purpose of assessing the level of impairment resulting from soft tissue injury involving a joint, whether the decision-maker has a discretion as to which Table will be used. A: There is no discretion: where both Tables 9.2 and 9.5 are applicable, the decision-maker must assess the degree of permanent impairment under that one of Tables 9.2 or 9.5 which yields the most favourable result to the employee. Q5. If a discretion exists as to which of two Tables will be used, on what basis that discretion ought to be exercised. A: Unnecessary to answer. THE COURT ORDERS THAT: 1. The respondent pay the applicant's costs of and incidental to the hearing of the referred questions of law. Note: Settlement and entry of orders is dealt with in Order 36 of the Federal Court Rules. IN THE FEDERAL COURT OF AUSTRALIA QUEENSLAND DISTRICT REGISTRY QG 194 of 1997 special case referred by the administrative appeals tribunal BETWEEN: DENNIS JOHN WHITTAKER Applicant AND: COMCARE Respondent JUDGES: DRUMMOND, COOPER AND FINKELSTEIN JJ DATE: 7 september 1998 PLACE: BRISBANE REASONS FOR JUDGMENT THE COURT This is a reference by the Administrative Appeals Tribunal of certain questions of law to this Court for determination pursuant to s 45 the Administrative Appeals Tribunal Act 1975 (Cth) and O 50 the Federal Court Rules. The object of the reference is to settle the proper construction of some provisions of the approved Guide prepared by Comcare pursuant to s 28 the Safety, Rehabilitation and Compensation Act 1988 (Cth) for use by it in determining the degree of permanent impairment resulting from injury to an employee claiming compensation. The questions have been referred to this Court in a proceeding brought by the applicant against the respondent for review of the determination by the latter's delegate that the applicant has, as a result of his left ankle injury, no compensible degree of impairment, as assessed in accordance with either Tables 9.2 or 9.5 of the Guide. The Safety, Rehabilitation and Compensation Act provides: Interpretation 4. (1) In this Act, unless the contrary intention appears: … "impairment" means the loss, the loss of the use, or the damage or malfunction, of any part of the body or of any bodily system or function or part of such system or function; … "permanent" means likely to continue indefinitely; … Compensation for injuries 14. (1) Subject to this Part, Comcare is liable to pay compensation in accordance with this Act in respect of an injury suffered by an employee if the injury results in death, incapacity for work, or impairment. … Compensation for injuries resulting in permanent impairment 24. (1) Where an injury to an employee results in a permanent impairment, Comcare is liable to pay compensation to the employee in respect of the injury. (2) For the purpose of determining whether an impairment is permanent, Comcare shall have regard to: (a) the duration of the impairment; (b) the likelihood of improvement in the employee's condition; (c) whether the employee has undertaken all reasonable rehabilitative treatment for the impairment; and (d) any other relevant matters. (3) Subject to this section, the amount of compensation payable to the employee is such amount, as is assessed by Comcare under subsection (4), being an amount not exceeding the maximum amount at the date of the assessment. (4) The amount assessed by Comcare shall be an amount that is the same percentage of the maximum amount as the percentage determined by Comcare under subsection (5). (5) Comcare shall determine the degree of permanent impairment of the employee resulting from an injury under the provisions of the approved Guide. (6) The degree of permanent impairment shall be expressed as a percentage. (7) Subject to section 25, where Comcare determines that the degree of permanent impairment of the employee is less than 10%, an amount of compensation is not payable to the employee under this section. … (9) For the purposes of this section, the maximum amount is $80,000. Approved Guide 28. (1) Comcare may, from time to time, prepare a written document, to be called the 'Guide to the Assessment of the Degree of Permanent Impairment', setting out: (a) criteria by reference to which the degree of the permanent impairment of an employee resulting from an injury shall be determined; (b) criteria by reference to which the degree of non-economic loss suffered by an employee as a result of an injury or impairment shall be determined; and (c) methods by which the degree of permanent impairment and the degree of non-economic loss, as determined under those criteria, shall be expressed as a percentage. (2) Comcare may, from time to time, by instrument in writing, vary or revoke the approved Guide. (3) A document prepared by Comcare under subsection (1), and an instrument under subsection (2), have no force or effect unless and until approved by the Minister. (4) Where Comcare, a licensed authority, a licensed corporation or the Administrative Appeals Tribunal is required to assess or re-assess, or review the assessment or re-assessment of, the degree of permanent impairment of an employee resulting from an injury, or the degree of non-economic loss suffered by an employee, the provisions of the approved Guide are binding on Comcare, the licensed authority, the licensed corporation or the Administrative Appeals Tribunal, as the case may be, in the carrying out of that assessment, re-assessment or review, and the assessment, re-assessment or review shall be made under the relevant provisions of the approved Guide. (5) The percentage of permanent impairment or non-economic loss suffered by an employee as a result of an injury ascertained under the methods referred to in paragraph (1) (c) may be 0%. (6) In preparing criteria for the purposes of paragraphs (1) (a) and (b), or in varying those criteria, Comcare shall have regard to medical opinion concerning the nature and effect (including possible effect) of the injury and the extent (if any) to which impairment resulting from the injury, or non-economic loss resulting from the injury or impairment, may reasonably be capable of being reduced or removed. (7) When a document prepared by Comcare in accordance with subsection (1), or an instrument under subsection (2), has been approved by the Minister, Comcare shall cause copies of the document or instrument, as the case may be, to be laid before each House of the Parliament within 15 sitting days of that House after the Minister receives those copies. … (9) Sections 48 (other than paragraphs (1) (a) and (b) and subsection (2)), 49 and 50 of the Acts Interpretation Act 1901 apply in relation to a document, being the approved Guide or an instrument varying or revoking that Guide that has been approved by the Minister, as if, in those sections, references to regulations were references to such a document and references to a regulation were references to a provision of such a document. (10) For the purpose of the application of the provisions of the Acts Interpretation Act 1901 in accordance with subsection (9), a document referred to in that subsection shall be taken to have been made on the date on which it was approved by the Minister under this section. Claims for compensation 54. (1) Compensation is not payable to a person under this Act unless a claim for compensation is made by or on behalf of the person under this section. (2) A claim shall be made by giving the relevant authority: (a) a written claim in accordance with the form approved by Comcare for the purposes of this paragraph; and (b) except where the claim is for compensation under section 16 or 17 - a certificate by a legally qualified medical practitioner in accordance with the form approved by Comcare for the purposes of this paragraph. … The whole of the section of the Guide, "9 Musculo-skeletal System", is appended to these reasons. But it is convenient to set out the opening part here: 9 MUSCULO-SKELETAL SYSTEM TABLE 9.1 Upper Extremity (Percentage Whole Person Impairment) Introduction - These tables are intended to be used to assess impairment arising from specific joint lesions or amputations. Where the joints function normally but the use of a limb is restricted for other reasons, eg soft tissue injury, nerve injury or bony injury not involving joints, Tables 9.4 or 9.5 should be used. These Tables can be used to assess the impairment of overall limb function from any cause. NOTE: either the musculo-skeletal table or Table 9.4 or 9.5 should be used - not both. Assessment is in accordance with the range of joint movement. X-rays should not be taken solely for assessment purposes. The body of Table 9.1 follows these words. There is a note to each of the six tables in Section 9 of the Guide stating that the various degrees of permanent impairment listed in each table are expressed as a "Percentage Whole Person Impairment". It appears from the Guide that this concept is a measure of the combined effect of the restriction resulting from the injury on uninjured whole body function and on the activities a normal healthy person must perform in daily living; it is not just a measure of the extent to which the normal functioning of the particular body part has been reduced by the injury. In the section of the Guide headed "Principles of Assessment", under the sub-heading "The Impairment Tables", the following appears: Part A of the Guide is based on the concept of 'whole person impairment' which is drawn from the American Medical Association's Guides. Evaluation of a whole person impairment is a medical appraisal of the nature and extent of the effect of an injury or disease on a person's functional capacity and activities of daily living. As with the American Medical Association's Guides, Part A of this guide is structured by assembling detailed descriptions of impairments into groups according to body system and expressing the extent of each impairment as a percentage value of the functional capacity of a normal healthy person. Thus a percentage value can be assigned to an employee's impairment by reference to the relevant description in this guide. Under the sub-heading "Impairment and Non-Economic Loss" it is said that: … Impairment is measured against its effect on personal efficiency in the 'activities of daily living' in comparison with a normal healthy person … Whilst 'activities of daily living' are used to assess impairment they should not be confused with 'lifestyle effects' which are used to assess non-economic loss. 'Lifestyle effects' are a measure of an individual's mobility and enjoyment of, and participation in, recreation, leisure activities and social relationships. It is emphasised that the employee must be aware of the losses suffered. While employees may have equal ratings of impairment it would not be unusual for them to receive different ratings for non-economic loss because of their different lifestyles. The "Glossary" in the Guide contains the following: Activities of Daily Living Activities of daily living are activities which an individual needs to perform to function in a non-specific environment ie to live. The measure of activities of daily living is a measure of primary biological and psychosocial function … Whole Person Impairment means the medical effects of an injury or a disease and is drawn from the American Medical Association Guides where it is there referred to as 'whole man' impairment. Evaluation of whole person impairment is a medical appraisal of the nature and extent of the effect of an injury or disease on a person's functional capacity and on the activities of daily living. The Guides are structured by assembling detailed descriptions of impairments into groups according to body system and expressing the extent of each impairment as a percentage value of of [sic] the functional capacity of a normal healthy person. Thus a percentage value can be assigned to an employee's impairment by reference to the relevant description in this Guide. The special case records that the applicant suffered an injury to his left ankle while performing duties as an employee of the Commonwealth; it also records the Tribunal's acceptance of the diagnosis made of the applicant's injury by a Dr Thompson, who: attributed the initial symptoms to a sprain of the lateral ligament and posterior capsule of the left ankle. Further, Dr Thompson stated that the x-ray reports were consistent with the lateral ligament being strained at its attachment on the lateral malleolus, 'taking a small piece of the bone with it which then united with the main body of bone'. The special case records Comcare's own acceptance of this injury as having left the applicant with a permanent impairment and certain conclusions reached by the Tribunal: 8. Thus, a joint is a functional entity and the integrity of the capsule and the ligaments of the ankle joint are essential structures of the joint itself. 9. This Tribunal has taken the view that where the introduction to the musculo-skeletal tables refers to 'soft tissue injury, nerve injury, or bony injury not involving joints', it is not intended that the term 'soft tissue injury' in this context should include tissues, hard or soft, which are an integral part of the functioning joint. Our interpretation is that Table 9.5 is to be used for injury to parts of the lower limb other than the relevant joints. Accordingly, in the case of the Applicant referred to above, it is our view that Table 9.2 is the applicable Table. … The questions of law referred to this Court are: 1. Whether, in the introduction to the musculo-skeletal system tables in the Guide, the expression "soft tissue injury" is qualified by the phrase "not involving joints", so that the indication for the use of Table 9.5, where soft tissue injury to the leg is concerned, is limited to soft tissue injury not involving joints. 2. Whether Table 9.2 is the applicable table in the case of injury to tissues which are integral to the joint. 3. Whether Table 9.5 can only be used in respect of injury to parts of the lower limb other than joints. 4. If both Table 9.2 and Table 9.5 are capable of being used for the purpose of assessing the level of impairment resulting from soft tissue injury involving a joint, whether the decision-maker has a discretion as to which Table will be used. 5. If a discretion exists as to which of two Tables will be used, on what basis that discretion ought to be exercised. Although it is not mentioned in the special case, the evidence before the Tribunal shows that both orthopaedic surgeons who have examined Mr Whittaker consider that his ankle injury has not left him with any loss of movement in the ankle joint. Dr Thompson considers that, while there is x-ray evidence of the old injury referred to above, there is no abnormality in Mr Whittaker's left ankle, the injury will not be associated with degenerative change in the future and that there is no percentage level of impairment, whether the injury is assessed under either Table 9.2 or 9.5. Dr Kinny's opinion, however, is that Mr Whittaker has a 10% impairment assessed according to Table 9.5: he has difficulties going up or down grades and soreness results if he attempts to do this without ankle support; his ankle gets sore after a lot of walking. This evidence, if accepted, establishes that his left ankle joint is not functioning normally as a result of his injury referred to in the case stated. It is apparent that if the Tribunal's view that Table 9.2 governs the case to the exclusion of Table 9.5 because Mr Whittaker's injury was confined to his ankle joint is correct, then even if it were to accept Dr Kinny's evidence, Mr Whittaker will not be entitled to any compensation, although he has suffered a permanent injury to his ankle as a result of which his ankle joint does not function normally. If it were permissible to assess the level of impairment under Table 9.5, however, he would, on Dr Kinny's evidence, be entitled to be paid compensation. The Guide is an important part of the scheme of employee compensation established by the Act. The Court was told that that part of the Guide, by reference to which the determination challenged by Mr Whittaker was made and which is headed "9 Musculo-skeletal System", has created difficulties in its application: there are a number of conflicting decisions of the Tribunal on aspects of this part of the Guide and we were told that it is applicable to a large number of compensation claims, which have been deferred pending the Court's decision in the present proceeding. Counsel for Comcare handed up to the Court a copy of the complete Guide. In Commission for the Safety, Rehabilitation and Compensation of Commonwealth Employees v Ticsay (1992) 38 FCR 181, Olney J, at 187, agreed with the Tribunal that it was not possible to give any sensible meaning to the note to Table 9.3. Six years later, the note remains in the Guide, unaltered. At 189, Olney J was critical of the way Tables 9.3 and 9.4 could yield anomalous results, but said that that "is inherent in the tables". The tables of present relevance, Tables 9.2 and 9.5, are open to the same criticism. In Comcare v Kay (1997) 26 AAR 124, Finn J, dealing with litigation that arose because of difficulty in interpreting the "Introduction" to Table 9.1, with which this Court is particularly concerned, said of it (at 131): What, nonetheless, is surprising is that in the face of the obvious deficiencies in explanation of Table 9's application, Comcare has persisted in promoting its ambiguity for so long. Despite much criticism by the Tribunals and Courts that have had to apply it over the years, it appears that Section "9 Musculo-skeletal System", if not the entire Guide, has remained unaltered since 1988. While it may, for practical reasons, be difficult for an agency to procure amendment by Parliament of a statute which it has to administer, Comcare is empowered by s 28(2) to act quickly, if only it chooses, to make any changes to the Guide that experience in its use identifies are necessary. For reasons of its own, however, Comcare appears to prefer constant litigation to that clarification of the Guide for which there has long been a manifest need. But this Court must attempt to make some sense of the provisions of the Guide that are of present relevance. It is plain that there are major deficiencies in the drafting of Section "9 Musculo-skeletal System" of the approved Guide. Although located within Table 9.1, the first paragraph, which commences with the words "Introduction - These tables are intended …" is plainly not an introduction just to Table 9.1. One possibility is that the paragraph was intended to be an introduction to all the tables in Section 9. But the content of this paragraph appears to be limited to the limbs, including limb joints. It probably should therefore be understood as an introduction only to Tables 9.1 to 9.5. The expression "These tables" in the first sentence of this "Introduction" may be intended to refer to Tables 9.1, 9.2 and 9.3 only: those three tables deal with the assessment of impairment due to joint injuries and to amputations (although there is no requirement in Tables 9.1 and 9.2 that the impairment must arise from a specific joint lesion). Finn J, in Kay at 130, however, considered that there was no reason to read this expression in this sentence as referring to anything other than "the entirety of Table 9", ie, all of Tables 9.1 to 9.6. Whatever be the tables to which the author of the Guide is referring in the third sentence of the "Introduction", he cannot have meant what he said about them being used to assess "the impairment of overall limb function": each of the tables in Section 9 of the Guide is a method for assessing something quite different, viz, "whole person impairment". If, however, this sentence is read as referring to tables that can be used to assess whole person impairment resulting from impairment of overall limb function, on no view can the expression, "These Tables", in this sentence of the "Introduction", refer to the entirety of the Tables in Section 9; it makes no reference to impairment from spinal injury (with which Table 9.6 deals). But the expression may be capable here of being read as a reference to Tables 9.1 to 9.5: between them, these five tables do enable the assessment of whole person impairment resulting from impairment of "overall limb function" from any kind of injury. However, Tables 9.4 and 9.5 are so worded as to enable the assessment of whole person impairment resulting from impairment of "overall limb function" from any cause: the expression "These tables" here can also be read as confirming that Tables 9.4 and 9.5 do themselves have this application. This is how Finn J read this sentence in Kay at 130 - 131. The "NOTE" at the end of this first paragraph can support such a reading: it can be speculated that what the author here intends to convey to the reader is a warning that, because Tables 9.4 and 9.5 do cover the entire field of impairment assessment due to injury to any element of the upper and lower limbs, it is necessary to ensure that the assessor does not double assess, eg, that he does not assess an ankle injury under Table 9.2 and also under Table 9.5. This "NOTE" is a good indication of the author's contempt for the notion that a person drafting a statutory instrument, especially one which governs people's entitlements, should take some care to convey his intention clearly. No single table or sub-group of the tables in Section 9 has any exclusive claim to be called "the musculo-skeletal table"; it may be that the author uses the term "musculo-skeletal table" in this "NOTE" as his code for Table 9.1 (whenever Table 9.4 may be equally applicable) and also for Table 9.2 (when Table 9.5 is applicable) and that he also uses it as his code for Table 9.3 (when either one of Tables 9.4 or 9.5 may also be applicable). The wording of the "NOTE" also suggests that it will always be open to the assessor to assess in accordance with "the musculo-skeletal table" (whatever it is) or either Table 9.4 or 9.5, ie, that in every case of injury to any part of the limbs, including joints, it will always be permissible to use Table 9.4 or 9.5, as well as the "musculo-skeletal table" (but not to double assess): the author may well have intended to convey something by this "NOTE" additional to a general warning against double assessment. The second paragraph of text at the commencement of Table 9.1 is plainly enough a note confined to that particular table, which deals with the assessment of impairment resulting from injury to specific upper limb joints: an identical note introduces Table 9.2, which deals with the assessment of impairment in respect of specific lower limb joints, while there is no corresponding note to any of the other tables which do not deal with joint movement impairment, but with impairment resulting from limb amputations, impairment of entire upper and entire lower limb function and impairment resulting from spinal injury. This paragraph serves two purposes: first, it describes the basis of assessment of whole person impairment in the two tables that deal with the effects of injuries to joints, viz, impairment of range of joint movement, and, secondly, it emphasises that, while x-ray evidence of the condition of the joint can be taken into account in making the movement-based assessment under Tables 9.1 and 9.2, radiological evidence must not control that assessment. There is no reason given in the Guide for adopting restriction of movement as the basis of assessment of impairment due to joint injury in Tables 9.1 and 9.2. It appears to be inconsistent with the statement in the section of the Guide, "Principles of Assessment": Impairment means 'the loss, loss of use, damage or malfunction, of any part of the body, bodily system or function or part of such system or function'. It relates to the health status of an individual and includes anatomical loss, anatomical abnormality, physiological abnormality and psychological abnormality. Throughout this guide emphasis is given to loss of function as a basis of assessment of impairment and as far as possible objective criteria have been used. (Emphasis added) As the medical evidence here shows, there may be no loss of movement, but there can be some loss of function of a joint: the terms are not interchangeable, as counsel for Comcare acknowledged. Movement is but one part of function. Weight bearing is another, at least so far as lower limb joints are concerned. And despite the unequivocal direction that the method of assessment of impairment in respect of the joints referred to in Tables 9.1 and 9.2 is by reference to the range of joint movement, the author has not attached any value to consistency. Neither Table 9.1 nor 9.2 is, in its terms, confined to providing for assessment of levels of impairment by reference only to impairment in the range of joint movement. In Table 9.1, "loss of function" of an injured joint, not loss of movement, governs whether the permanent impairment resulting from the injury is assessed at 0% or 5%; the other levels are all assessed by reference to impairment of range of movement in the joint. Table 9.2 makes "loss of function" of a lower limb joint the basis for the 0% assessment of level of impairment only, with impairment of range of movement being the relevant consideration, in the rest of that Table. Moreover, the notes at the foot of Table 9.2 revert, without explanation, to requiring assessment in the case of a surgically replaced joint to be in accordance with function, not range of movement. It can be speculated, in view of the direction in the second paragraph as to the method of assessment provided for by Tables 9.1 and 9.2, that the author may have here used the terms "movement" and "function" interchangeably in these two tables. But one cannot be sure. It is this same lack of consistency in the use of language which has led to the difficulties the subject of the case stated. The respondent contends that the first sentence in the "Introduction" in Table 9.1 should be read as referring to Tables 9.1, 9.2 and 9.3 and that this sentence and the second sentence should therefore be read as making Table 9.2 the only table applicable to any kind of injury to a lower limb joint, irrespective of whether the injury is to bony or non-bony elements of the joint; on this approach Table 9.5 is confined to the residue of lower limb injuries. This is the approach the Tribunal in the case stated indicates it favours. However, respondent's counsel acknowledges that to reach this result, it is necessary to resolve in Comcare's favour difficulties with the language of the "Introduction" that we have not yet mentioned: counsel for Comcare accepted that unless the phrase "not involving joints", in the second sentence, was read as qualifying each of the preceding examples of injury, it was difficult to justify its proposed construction. Counsel also accepted that, if the first sentence is to be read as Comcare contends, the necessary implication is that the author of the Guide regarded all limb joints not referred to in either Tables 9.1 or 9.2, eg, certain joints in the mid-foot, as not sufficiently significant to attract compensation, however extensively they may be damaged. Counsel therefore submitted that the phrase "specific joint lesions" in this sentence should be read as confirming the application of the Tables the subject of this first sentence to impairments of any significance, viz, to impairments resulting specifically from joint lesions rather than to such impairments as may arise from lesions to the particular joints referred to in Tables 9.1 and 9.2. It is unnecessary to decide whether both submissions are well-founded. They do, however, further highlight the difficulties in applying Section 9 of the Guide, which result from the author's failure to recognise the value of clarity in identifying the objectives to be achieved and clarity in the choice of language to give effect to those objectives. It is difficult to identify with any confidence what the author of the Guide intended was to be the role of Tables 9.2 and 9.5. The proposition that Table 9.2 is the only table under which lower joint injury caused impairment can be assessed is supported by the opening words of the second sentence, which suggest that the first sentence deals with all abnormal conditions of the joints for which compensation can be payable; it is, however, inconsistent with the "NOTE" at the end of the paragraph which seems to envisage that it is always open to assess such impairment under Table 9.5, even though Table 9.2 may also be applicable, so long as double assessment is avoided. In view of the clear statement that joint injury caused impairment is to be assessed "in accordance with the range of joint movement", it may be that the author mistakenly assumed that the only possible impediment to normal joint function is a specific joint lesion resulting in restriction of joint movement, so that "[w]here the joints function normally" should be understood to mean "[w]here there is no restriction in joint movement". But he may really have intended to exclude from compensation all injuries to the limbs, no matter how severely they impair limb function and how severe a whole person impairment that causes, unless they take the form of specific lesions to joints that restrict joint movement. There is evidence extrinsic to the Guide that suggests that this was the author's intent. (Whether it is beyond the power conferred by s 28(1) of the Act for Comcare to adopt a Guide that so restricts the entitlements to compensation which the Legislature has conferred on employees who suffer impairment from the wide range of causes within the definition of "injury" in s 4 of the Act was not raised in argument and need not be pursued now.) The preface to the Comcare Guide states that the main sources of reference for its development were Guides to the Evaluation of Permanent Impairment, American Medical Association, Chicago, 1984 and Guide to the Assessment of Rates of Veterans' Pensions, Department of Veterans' Affairs ("DVA Guide"). We have looked at the 1985 third printing of the AMA Guides. It would appear that it is not the version used by Comcare: it refers to "whole person impairment" rather than to "whole man impairment", the expression apparently employed in that version of the AMA Guides used by Comcare. Chapter 1 of the 1985 AMA Guides deals with "the extremities, spine and pelvis". It provides for a much more elaborate and precise procedure for assessing the degree of impairment of each of the body parts or systems covered by its fifty-three tables and then whole person impairment than does Section 9 of the Comcare Guide, consisting of only six tables. It is clear that the Comcare Guide has derived from the AMA work the concept of "whole person impairment", the assessment of which is the objective of the Comcare Guide. But there is nothing that we can see in the AMA Guides that can be identified as the source of the text in Table 9.1 or of any of the tables in Section 9 of the Comcare Guide. However, the source of Tables 9.1 and 9.2 appears pretty clearly to be the first (1986) edition of the DVA Guide (now in its fifth, extensively altered edition). The descriptions of the various levels of impairment in Comcare's Tables 9.1 and 9.2 closely mirror the corresponding descriptions in Table 12.1 "Upper Extremity" and Table 12.2 "Lower Extremity" in the section headed "Musculo-Skeletal" in the 1986 edition of the DVA Guide. There is an introductory note to Tables 12.1 and 12.2 - "Assessment is made according to observed range of movement" - that corresponds to the statement that heads both Tables 9.1 and 9.2 of the Comcare Guide and, despite this note in the DVA Guide and the corresponding note in the Comcare Guide, Tables 12.1 and 12.2, like Comcare's Tables 9.1 and 9.2, both move without explanation from assessment on the basis of loss of "function" to assessment by reference to "range of movement". The general focus in Tables 12.1 and 12.2 of the DVA Guide on restriction of movement is, like the similar focus in Tables 9.1 and 9.2 of the Comcare Guide, inconsistent with the stated basis of assessment of "Impairment" defined in the DVA Guide as follows: Impairment is the purely medical condition from which all other elements of incapacity usually stem. It refers to any anatomic or functional abnormality or loss remaining after the appropriate medical and rehabilitative processes have been completed. It is the element of incapacity most capable of accurate and objective measurement as it is evidenced by loss of structural integrity and functional capacity and pain that is substantiated by clinical findings. It includes substantiated pain. The inference is strong that Comcare, in Tables 9.1 and 9.2, copied Tables 12.1 and 12.2 of the 1986 DVA Guide. But Comcare incorporated in its Guide some provisions of its own that have no counterparts in this early version of the DVA Guide: there is nothing in it that corresponds to Comcare's Tables 9.4 and 9.5. Nor is there anything in the 1986 DVA Guide comparable to the "Introduction" paragraph in Comcare's Table 9.1: that obfuscation is all the work of the author of the Comcare Guide. The operation of the 1986 DVA Guide was free from doubt: Tables 12.1 and 12.2 (with the amputation table 12.4) provided the only methods initially adopted by the Repatriation Commission pursuant to ss 22(4) and 29(1) the Veterans' Entitlements Act 1986 (Cth) for the assessment of degrees of "whole person impairment" resulting from war-related injury to the upper and lower limbs. Tables 12.1 and 12.2 permitted assessment of overall limb impairment and thus whole person impairment only if there was joint movement restriction. Although the Comcare Guide, in Tables 9.1 and 9.2, copied Tables 12.1 and 12.2 pretty well exactly, it goes on to include in Section 9 Tables 9.4 and 9.5, which themselves provide for assessment of whole person impairment by reference to impairment in overall limb function. The presence of these Tables in Section 9 is inconsistent with Tables 9.1 and 9.2 comprising the sole method for assessing whole person impairment resulting from overall limb impairment. Comcare appears, in Tables 9.4 and 9.5, to have accepted that limbs may be injured, and thus whole person impairment may result, without the joints or joint movement being involved. It also appears to have recognised that it could not include in its Guide two tables (9.1 and 9.2) copied from a model designed to provide the sole, but very restrictive, method for assessing whole person impairment due to limb injury and two other tables (9.4 and 9.5) providing a more expansive method for assessing the same whole person impairment, without stating how the conflict between the two sets of tables was to be resolved. The "Introduction" paragraph in Table 9.1 was probably intended to serve this purpose. Unfortunately, the author appears to have given insufficient thought to why it was necessary to copy Tables 9.1 and 9.2 from the DVA Guide when he had also determined to adopt Tables 9.4 and 9.5 of his own and to have given little thought to stating, with the clarity required, how these two sets of Tables were to be applied. Not only is there the apparent, but unexplained lack of consistency in the use of terms (eg, "function" and "movement"), careless choice of expression (eg, what is meant by such phrases as "the musculo-skeletal table" and "[w]here the joints function normally …"), there are also contradictory indications, on the one hand, that Tables 9.2 and 9.5 are both applicable in any given case (eg, in the third and fourth sentences of the "Introduction" paragraph) and, on the other hand, that these two tables have mutually exclusive areas of operation (eg, as is suggested in the first two sentences of the "Introduction" paragraph and by the model from which Table 9.2 was copied). It was said in Scott v Moses (1958) 75 WN(NSW) 101 at 102 that, whatever the difficulties of construction may be, a court is bound to give some meaning to a provision in a statute "and upon no proper principles could a court ever hold that an Act of the legislature was to be regarded as a nullity because of the uncertainty of the language used". Bennion, in Statutory Interpretation 3rd ed (1997) at 352, goes so far as to say that, when confronted with an obscure provision, "the judge is nevertheless compelled to find a meaning (which in some cases amounts to saying that the judge must virtually invent one)". The general rule is that the same approach is taken to the interpretation of a delegated statutory instrument as it is to interpreting the statute itself (although uncertainty of expression is a ground, not argued here, on which delegated legislation may be held invalid as beyond the statutory power that authorises its making. See King Gee Clothing Co Pty Ltd v The Commonwealth (1945) 71 CLR 184 at 195 - 196.). The court can call in aid wide powers when it has to try to give effect to confused statutory language. If a court concludes that the literal meaning of a provision does not conform to the legislative purpose, the court can give effect to that purpose by addition to, omission from, or clarification of the particular provision: Saraswati v The Queen (1991) 172 CLR 1 at 22. There is no reason to doubt that the court has the same powers at its disposal when it is confronted with the task of giving effect to confused statutory language. But there are limits to the court's interpretative powers: cf Mills v Meeking (1990) 169 CLR 214, where, speaking of an injunction to the court contained in a provision similar to that in s 15AA the Acts Interpretation Act 1901 (Cth), to give effect, in construing it to the purpose of the statute, Dawson J said, at 235, that such a provision: "requires a court to construe an Act, not to rewrite it, in the light of its purposes". See also McHugh J at 243 - 244. Despite the statement in Bennion, a court, in our opinion, can only be justified in using the more radical techniques of interpolation, excision and rewriting, if it can identify the intent or purpose of the statutory provision. The object of all interpretation is to discover that presumed intent (or purpose). See Corporate Affairs Commission (NSW) v Yuill (1991) 172 CLR 319 at 321 - 322 and 345 - 346; Mills v Meeking at 233 - 234. It is an intent to be gathered from the language used, in its context and with the aid of those materials to which the court can properly have recourse in seeking that intent. However, if it is not possible for the Court to be confident of the intent of the author, it is not, we think, open to the Court to invent, under the guise of interpretation, its own version of how it thinks the text might read. That is, in the present context, it is not open to this Court to devise a text of its own in place of the garbled original that reflects how the Court may think Comcare could have performed the duty cast on it by s 28(1) of the Act. This is plainly so where the Court has to construe a Guide to the assessment of injury-caused impairment which deals with matters of some technical complexity, a complexity masked by the apparent simplicity of Section 9 of the Comcare Guide, but obvious, when regard is had to the corresponding provisions of the current DVA Guide and the AMA Guides. For the reasons given, in view of the confused language and the contradictory indications in the text of the first paragraph in Table 9.1 as to what the author really intended was to be the operation of Tables 9.2 and 9.5, we do not think the Court can have any degree of confidence that rewriting of the text that is undoubtedly necessary to give it a sensible operation would truly give effect to the intention of the author of the Guide. But because it is uncertain whether the author of the Guide intended Tables 9.2 and 9.5 to have an overlapping or a mutually exclusive operation and (if the former was intended) because it is uncertain what the author considered should be the inter-relationship between the two tables, the Court is entitled to resolve the issues of interpretation raised by the case stated by adopting the approach referred to in Ticsay. Olney J, at 188, there said: The first principle established by the authorities is clearly stated by Hill J in Thiele v Commonwealth (1990) 22 FCR 342 at 346 when he said in relation to the precursor of the Act: 'The present legislation is socially remedial legislation intended to benefit workers and should be given a construction which advances its purposes as such. Thus where two constructions are possible, that which is favourable to the worker should be preferred: Wilson v Wilson's Tile Works Pty Ltd (1960) 104 CLR 328 at 335 per Fulmar J.' Reference was also made to the dictum of Gibbs J (as he then was) in Public Transport Commission (NSW) v J Murray-More (NSW) Pty Ltd (1975) 132 CLR 336 at 350: '[W]here two meanings are open … it is proper to adopt that meaning that will avoid consequences that appear irrational and unjust.' Having regard to the definition of the term "impairment", to the provisions of ss 14 and 24, and to the particular purpose of the Guide as provided in s 28(1), it seems that the legislative policy of the Act is to provide for the payment of compensation to an employee who has suffered an injury resulting in a permanent impairment. The Guide should be construed and applied in aid of the general statutory purpose, not as a means of limiting it. A number of points can be made from the statutory context of the Guide. The first is that the general principle of the Act, in so far as it makes provision for Commonwealth employee compensation, is that contained in s 24(1), viz, that compensation is payable where an employee suffers an injury that results in a permanent impairment. The second point is that s 24(7) shows that it is only where Comcare determines, by applying the Guide, that the employee's degree of permanent impairment is less than 10% that the employee is disentitled to compensation in respect of the injury already determined to have resulted in permanent impairment. Only then will there be an exception to the general principle in s 24(1). The general legislative purpose or intent is that an employee who suffers injury causing more than minor permanent impairment is entitled to compensation. The third point is that it is only permissible for Comcare to turn to the Guide once it has reached the conclusion, after taking into account the matters listed in s 24(2) of the Act, that the employee has suffered an injury which has resulted in a permanent impairment. The Guide then becomes relevant, but only in so far as it contains the criteria by reference to which Comcare must assess the degree of that employee's permanent impairment. The Guide, which has this limited role, should not be allowed to limit the general legislative purpose. Adopting the approach in Ticsay, we would therefore answer the questions raised by the case stated as follows. Question 1 Table 9.5 can be used for the assessment of the degree of permanent impairment resulting from injury to any part of the lower limb, including to any part of a joint. Question 2 Table 9.2 can be used to assess the degree of permanent impairment resulting from injury to a joint in the lower limb irrespective of whether the structures of the joint injured are limited to non-bony elements, but only where the assessment under Table 9.2 results in a higher degree of impairment than would assessment under Table 9.5. Question 3 No Question 4 There is no discretion: where both Tables 9.2 and 9.5 are applicable, the decision-maker must assess the degree of permanent impairment under that one of Tables 9.2 or 9.5 which yields the most favourable result to the employee. Question 5 Unnecessary to answer. We would order Comcare to pay the respondent's costs of the case stated. I certify that this and the preceding nineteen (19) pages are a true copy of the Reasons for Judgment herein of the Court. Associate: Dated: 7 September 1998 Counsel for the Applicant: Mr DP O'Gorman Solicitor for the Applicant: Trenches Counsel for the Respondent: Ms CE Holmes Solicitor for the Respondent: Australian Government Solicitor Date of Hearing: 15 July 1998 Date of Judgment: 7 September 1998