The extent of conclusiveness
57 What follows is not essential to my conclusion. Whether under the unamended Act the medical assessor's certificate was conclusive as to degree of permanent impairment (s 61(2)(a)), and only evidence as to causation of that permanent impairment by the motor accident (s 61(3)), was not clearly debated at the hearing. At least initially, the applicant's position was that the certificate was not conclusive as to causation, although that became rather obscure. The Court was referred to Ackling v QBE Insurance (Australia) Ltd [2009] NSWSC 881, in which Johnson J held to the contrary (see later in these reasons). The non-conclusivity of the certificate as to causation was questioned with reference to ss 131 and 132. Recognising the incomplete debate, my view of the unamended Act in this respect should be expressed as part of the statutory context.
58 Where there was medical assessment of the degree of permanent impairment under the Act, the statutory function of the certificate was to establish whether or not the 10 per cent threshold in s 131 was reached. The assessment did not thereafter confine the award of damages for non-economic loss: for example, if the assessed degree of impairment was 15 per cent, to 15 per cent of maximum damages for non economic loss stipulated in or under s 134 of the Act (Hodgson v Crane [2002] NSWCA 276; (2002) 55 NSWLR 199). The only function was to open, or keep closed, the gateway to an award of damages for non-economic loss. (Perhaps for that reason, the 2007 Act amended s 58(1)(d) specifically to refer to the 10 per cent threshold, rather than degree of permanent impairment in general.)
59 The statement of the threshold in s 131 contained the composite phrase, "the degree of permanent impairment of the injured person as a result of the injury caused by the motor accident", with the two elements of degree of permanent impairment and of causation of the degree of permanent impairment. The same phrase with its two elements was found in ss 131, 133(1) and 58(1)(d).
60 Other provisions in Pt 3.4 used the shorter phrase, "the degree of permanent impairment" (s 61(2)(a), (b); s 132(1), (2), (3); s 133(2)). Sometimes the phrase was related to the requisite percentage (s 61(2)(a); s 61(6)), without express reference to the element of causation.
61 That element must, however, be read into the use of the shorter phrase. Assessment of degree of permanent impairment without regard to causation from the motor accident was not relevant to determining whether the threshold in s 131 was reached, and would depart from the description of the matter in s 58(1)(d). A medical assessment of degree of permanent impairment without regard to causation from the motor accident had no statutory basis or function. That the shorter phrase included the element of causation is clear from its use in s 132, because the point of the degree of permanent impairment was sufficiency for an award of damages for non-economic loss. It is also clear from s 133(2), because the shorter phrase related back to the composite phrase in s 133(1).
62 It was the same, in my opinion, where s 61(2)(a) and s 61(6) referred to a certificate "as to whether the degree of permanent impairment of the injured person is greater than 10%". This meant permanent impairment as a result of the injury caused by the motor accident. The conclusive effect of such a certificate extended to the element of causation, and the determination by the court of the degree of permanent impairment of the injured person, permitted under s 61(6), had to be assessed in accordance with s 133 which implicitly referred back to the composite phrase in s 133(1). The non-conclusive effect as to other matters (see s 61(3)) still had work to do in relation to the impairment of earning capacity (and possibly for other purposes, see Pham v Shui [2006] NSWCA 373; (2006) 47 MVR 231, below, but that is another matter).
63 Section 62(2) now refers to a certificate "as to a medical assessment matter", and this conclusion is clear on the terms of the amended Act. Prior to the amendment by the 2007 Act, in my opinion the shorter phrase picked up the whole of the matter in s 58(1)(d). The conclusiveness of the medical assessment, as certified, included the medical assessor's finding that the permanent impairment was or was not as a result of the injury caused by the motor accident.
64 In Ackling v QBE Insurance (Australia) Ltd at [80] Johnson J correctly so held. In this Court it was rather indirectly suggested that Pham v Shui stands for the contrary position. I do not think it does.
65 In Pham v Shui the trial judge held that the certificate of a review panel conclusively established the degree of permanent impairment and whether the degree of permanent impairment was caused by the motor accident, and that the conclusiveness extended to assessment of both non-economic loss and economic loss. The trial judge gave the certificate conclusive effect by accepting, and accepting only, the injuries found by the assessor to have been sustained in the motor accident. The certified degree of permanent impairment was less than 10 per cent, and this effect was given in arriving at damages for economic loss.
66 On appeal Santow JA, with whom Bryson JA and Brereton J agreed, held at [90] that the certificate "was required for the purpose of determining whether, within s 131 of the MACA, damages could be awarded for non-economic loss", and that s 61(2)(a) "can have no other meaning than that the certificate's conclusivity applies only to the bare conclusion that the degree of permanent impairment for that purpose was (or was not) greater than 10%".
67 His Honour's reasons were concerned with conclusiveness for the purpose of assessing economic loss. He went on to say, with reference to the reasons of Mason P in Brown v Lewis [2006] NSWCA 87; (2006) 65 NSWLR 587, that he did not exclude the relevance of a non-conclusive certificate to assessing economic loss but "extreme caution" was required as to likely relevance. This issue does not arise in the present case.
68 The reasons of Santow JA included, however, reference to "caused by the motor accident" in s 58(1)(d), and his Honour said -
"[96] Mr Stitt, QC for the opponent placed great emphasis on the words "caused by". He contended that this language, with other textual indications, meant that the certificate was conclusive as to what he called the medical aetiology, meaning the medical causation of the relevant "injury". So much can be accepted. But what does not follow is that the certificate, incorporating as it does reasons which may range from surmise to certitude, are thereby rendered conclusive, outside of the strict limits of s 61(2). In particular there is no conclusivity extending to a matter outside s 61(2) such as that in s 58(1)(d) (the degree of permanent impairment of the injured person as a result of the injury caused by the motor accident). Rather, matters falling outside s 61(2) are simply capable of constituting evidence, but not conclusive evidence, as to the non-s 61(2) matters in so far as they are "certified" in terms of s 61(3)."
69 I do not understand his Honour to have said that the conclusiveness in s 61(2)(a) did not include causation by the motor accident. That was not the issue. In saying that the conclusiveness did not extend to something outside s 61(2) "such as that in s 58(1)(d)", I understand his Honour to have been referring to the particular degree of permanent impairment as a result of the injury caused by the motor accident, for example a degree of 7 per cent or 15 per cent, as distinct from whether the degree of permanent impairment was or was not greater than 10 per cent.