(2) Any such certificate as to:
(a) whether the degree of permanent impairment of the injured person is greater than 10%, or
(b) whether any treatment already provided to the injured person was reasonable and necessary in the circumstances, or
(c) whether an injury has stabilised,
is conclusive evidence as to the matters certified in any court proceedings or in any assessment by a claims assessor in respect of the claim concerned.
(3) Any such certificate as to any other matter is evidence (but not conclusive evidence) as to the matters certified in any court proceedings or in any assessment by a claims assessor in respect of the claim concerned.
(4) In any court proceedings, the court may (despite anything to the contrary in this section) reject a certificate as to all or any of the matters certified in it, on the grounds of denial of procedural fairness to a party to the proceedings in connection with the issue of the certificate, but only if the court is satisfied that admission of the certificate as to the matter or matters concerned would cause substantial injustice to that party.
(5) If a certificate as to any matter is rejected under subsection (4), the court is to refer that matter again for assessment under this Part and adjourn the proceedings until a further certificate is given and admitted in evidence in the proceedings.
(6) However, if a certificate as to whether or not the degree of permanent impairment of the injured person is greater than 10% is rejected under subsection (4), the court may, if it considers it appropriate, substitute a determination of the court as to the degree of permanent impairment of the injured person (assessed by the court in accordance with section 133) instead of referring that matter again for assessment under this Part.
(7) Except as provided by subsection (6), a court may not substitute its own determination as to any matter referred to in subsection (2) (a), (b) or (c).
(8) This section:
(a) does not prevent a court from referring a matter again for assessment under this Part (as provided for by section 62), and
(b) does not require a court to refer a matter again for assessment under this Part if the matter is not a matter referred to in subsection (2) (a), (b) or (c).
(9) A certificate is to set out the reasons for any finding by the medical assessor or assessors as to any matter certified in the certificate in respect of which the certificate is conclusive evidence."
22 Section 63 provides:
"(1) A party to a medical dispute may apply to the proper officer of the Authority to refer a medical assessment under this Part by a single medical assessor to a review panel of medical assessors for review.
(2) An application for the referral of a medical assessment to a review panel may only be made on the grounds that the assessment was incorrect in a material respect.
(3) The proper officer of the Authority is to arrange for any such application to be referred to a panel of at least 3 medical assessors, but only if the proper officer is satisfied that there is reasonable cause to suspect that the medical assessment was incorrect in a material respect having regard to the particulars set out in the application.
(4) The review panel may confirm the certificate of assessment of the single medical assessor, or revoke that certificate and issue a new certificate as to the matters concerned.
(5) Section 61 applies to any such new certificate."
23 The parties correctly said that neither the Explanatory Memorandum nor the Second Reading Speech offered any assistance in the task of construing the legislation.
24 It was also common ground between the parties, whose respective senior counsel appearing before this Court are of very great experience in the field, that the 10% permanent impairment threshold established by s 131 was extremely difficult to satisfy. They said that leaving aside special classes to whom s 131 does not apply, such as children, quadriplegics and paraplegics, only about ten persons per annum had passed through the s 131 threshold. Yet a generation ago there were tens of thousands of motor accident cases commenced each year without any threshold.
25 In the absence of MAA Medical Guidelines, the American Medical Association's Guides to the Evaluation of Permanent Impairment, Fourth Edition, apply. They turn on "whole of body" tests. Those tests are applied by medical assessors under s 61. The certificate of the assessors is conclusive on certain matters, including whether the degree of permanent impairment exceeds 10%. A certificate can only be rejected by the court where there is procedural unfairness and the court considers that admission of the certificate would cause a substantial injustice. There is an evident legislative intention to depart from the thresholds adopted under the 1988 Act defined by reference to particular percentages of a most extreme case. Those thresholds inevitably turned on matters of impression, judgment and degree, and permitted courts in practice to be more generous than the legislature had perhaps desired. There is also an evident legislative intention, in relying on a purely physical basis of the American Medical Association's Guides, to ignore the dramatic effect on some plaintiffs of relatively minor injuries. A barrister or accountant or businessman who lost a finger might have experienced a very low percentage of permanent impairment on a whole of body basis, and indeed might recover very low damages at common law; but a great violinist or a skilled craftsman in the same position might have lost a great deal. Parliament has chosen to leave that consideration out of account in providing for the s 131 threshold. Similarly, a young adult who lost part of the function of its right leg has the same percentage of whole of body impairment as a very old man with the same injury: the former's loss will be experienced for much longer than the latter's and is likely to be much greater, but s 131 ignores the difference.
26 The defendants contended that the assessment by medical assessors of permanent impairment was not limited to whether the degree of permanent impairment exceeded 10%, but operated more generally. Part 3.4 was, it was submitted, a crucial part of the legislation, taking away the court's power in large measure to decide on the degree of permanent impairment. The defendants pointed out that s 132(2) provided that the court's power to refer the matter for assessment of the degree of permanent impairment was not limited to the initial stage of the proceedings, when questions of the 10% gateway might be expected to arise, but was a power which could be exercised at any stage. The defendants submitted that it was "difficult to see why once a gateway had been accessed a Court would send it off unless this permanent impairment concept had another job to do in relation to the overall assessment." On this submission, the matters caught by the expression "any other matter" in s 61(3) included issues as to what the degree of permanent impairment was above 10%. The defendants also pointed to s 133(1): it did not provide that the assessment of the degree of permanent impairment was either 10% or less, or over 10%, it provided that the degree, whatever it was, was to be expressed as a percentage. If so, that precise percentage, if it were above 10%, must have some role to play in assessing damages.
27 The defendants then contended that that group of arguments pointed towards proportionality as being a proper approach, and submitted that that approach was also supported by the s 134 cap. They frankly admitted, however, that they could point to no other argument for that view, nor to any useful canon of statutory construction.
28 The defendants' arguments are invalid.
29 It is a legitimate aid to statutory construction to read an Act as a whole in order to ascertain the statutory scheme in its totality. Where succeeding Acts having both similarities with and differences from each other deal with a single subject, it must equally be legitimate to ascertain and compare the succeeding statutory schemes. In this way the function of particular provisions within each scheme is illuminated. The introduction of particular provisions can be seen to have particular significance in the light of what has been retained and what has been removed. See generally Geaghan v D'Aubert [2002] NSWCA 260 at [22]-[24].
30 In effect the defendants' arguments attempted to give the 1999 legislation the same construction as that borne by the 1988 legislation. This approach was condemned by Dixon and Evatt JJ in Brennan v R (1936) 55 CLR 253 at 263:
"[statutory] language should be construed according to its natural meaning and without any presumption that it was intended to do no more than restate the existing law. It is not the proper course to begin by finding how the law stood before the [Criminal Code (WA)], and then to see if the Code will bear an interpretation which will leave the law unaltered."
31 In its final form, s 79 of the Motor Accidents Act 1988, which applied to the determination of non-economic loss in relation to motor accidents occurring before midnight on 26 September 1995, relevantly provided:
"(1A) The object of this section is to limit the amount of damages for non-economic loss in cases of claims relating to relatively minor injuries, in order to achieve the object of the Act of more fully compensating those with more severe injuries at a cost the community can afford to meet.
(1B) No damages shall be awarded for the non-economic loss of an injured person as a consequence of a motor accident unless the injured person's ability to lead a normal life has been, or in the near future is likely to be, significantly impaired for a continuous period of not less than 6 months by the injury suffered in the accident.
(2) The amount of damages to be awarded for non-economic loss shall be a proportion, determined according to the severity of the non-economic loss, of the maximum amount which may be awarded.
(3) The maximum amount which may be awarded for non-economic loss is $180,000, but the maximum amount shall be awarded only in a most extreme case.
(4) If the amount of non-economic loss is assessed to be $15,000 or less, no damages for non-economic loss shall be awarded.
(5) If the amount of damages to be awarded for non-economic loss in accordance with this section is more than $15,000 but less than $55,000, the following deductions shall be made from that amount:
(a) if the amount of damages is less than $40,000 the amount to be deducted is $15,000,
(b) if the amount of damages is not less than $40,000 the amount to be deducted is $15,000, or $15,000 reduced by $1,000 for every $1,000 by which the amount of damages exceeds $40,000."
32 Section 79A, which applied to the determination of non-economic loss in relation to motor accidents occurring after midnight on 26 September 1995 until the Motor Accidents Compensation Act 1999 came into force on 5 October 1999, stated the same object as s 79(2), and further provided:
"(3) No damages are to be awarded for the non-economic loss of an injured person as a consequence of a motor accident unless the injured person's ability to lead a normal life has been, or in the near future is likely to be, significantly impaired for a continuous period of not less than 12 months by the injury suffered in the accident.
(4) No damages may be awarded for non-economic loss unless the severity of the non-economic loss of the injured person is at least 15 per cent of a most extreme case.
(5) The maximum amount that may be awarded for non-economic loss is $235,000, but the maximum amount is to be awarded only in a most extreme case.
(6) If the severity of the non-economic loss is assessed to be equal to or greater than 15 per cent of a most extreme case, the damages for non-economic loss are to be determined according to the following Table … ."