The sales evidence to which he was referring was the historic land sales which his Honour rejected as lacking comparability.
43 That this was the thrust of Mr Hill's evidence was further illustrated in the following exchange in his evidence in chief:
"Q. I understand your primary contention is that when there are other methods of valuation, to apply the depreciation rate method that's been done you disagree with?
A. Correct."
44 The appellants submitted, and his Honour acknowledged (at [63]), that Mr Jackson adopted the method prescribed for the depreciation of improvements in the standard valuation text, Rost & Collins, "Land Valuation & Compensation in Australia" 3rd Ed at pp 122-125. It was acknowledged that Rost & Collins is a well-known and highly regarded valuation text.
45 It is clear from the part of Rost & Collins referred to that the depreciation of improvements is one of the skills that a qualified valuer is required to bring to bear in an appropriate case in the valuation exercise. In terms of that exercise, the learned authors state that depreciation
"may be measured by the difference between the value which a building or other improvement adds to the land at the time of valuation and the amount it would cost to replace it (new) at that time".
46 Physical deterioration, functional and economic obsolescence must all be taken into account. At page 125 the authors make this statement:
"In assessing loss as a value due to physical, functional or economic depreciation, the objective is to ascertain the market value of the improvement. If market transactions do not provide evidence of such value, the valuer must rely largely on his own judgment and experience supported by such tests as may be practicable and taking into account wear and tear, standard of maintenance and degree of obsolescence of each improvement."
47 Nowhere do the learned authors suggest or comment upon the wisdom or otherwise of adopting a single depreciation rate or as to whether there are differences between depreciating the value of buildings of different types. In particular, they do not suggest that it is outside a valuer's expertise and/or unreliable to adopt a single depreciation rate in respect of a high-rise commercial office building. Although the third and latest edition of the text was prepared in 1984, albeit that it has gone through a number of reprints since, nevertheless high rise commercial office buildings in CBDs were well known and understood at that time.
48 In Maurici, the High Court observed (at 121 [19]) that improved sales of land were used daily for the purpose of statutory valuations under provisions similar to s 6A(1) of the Act by subtracting the added value of the improvements from their sale prices to derive unimproved land values. One can accept that in determining the added value of the improvements to land, their Honours would have understood that a depreciation rate in respect of the existing improvements would need to be adopted. But the Court in Maurici was dealing with dwelling houses in Hunters Hill in respect of which the determination of a single depreciation rate would in all probability present little difficulty to an experienced valuer. So much seems to have been acknowledged by Mr Hill. The Court was not, however, dealing with high-rise commercial office buildings of significant complexity in terms of their components when compared to a dwelling house including what their Honours referred to as the "many mansions" in an area such as Hunters Hill.
49 However, the manner in which the primary judge dealt with the question of depreciation in [67] of his judgment leads me to the conclusion that he was propounding a principle of general application. It is true that his Honour says that he accepts Mr Hill's evidence that separate depreciation rates would need to be applied to the components of the building if an accurate land value assessment is to be derived. It is also true that Mr Hill's evidence, at least on one view of it, related his requirement for separate depreciation rates to the various components of high-rise commercial office buildings. But then it also related his rejection of Mr Johnson's method of depreciation to the availability, as he saw it, of other and better sales evidence, namely, the historic land sales.
50 It is apparent that his Honour does not make it clear that it was only a particular type of building he was referring to when he opined that the adoption of a single depreciation rate was too simplistic, assuming that was his intention. In any event, it is tolerably clear that, in accepting Mr Hill's evidence, his Honour was at least propounding a principle of general application for high-rise commercial office buildings.
51 If my understanding of [67] is correct, then the primary judge has made an error in valuation principle. It cannot be correct that a single depreciation rate for improvements can never be used to derive land value whether in respect of all buildings or even all high-rise buildings.
52 However, I prefer to base my rejection of his Honour's finding on what I regard as a more solid basis. For that purpose I shall assume that the third interpretation of [67] of the judgment referred to in [40] above is correct. It is well-established that it is an error of law for a court to reject as wholly irrelevant, for grounds which are not rational, a sale or sales which, prima facie, afford some evidence of value: Melwood Units Pty Ltd v Commissioner of Main Roads [1979] AC 426 at 432; Leichhardt Municipal Council v Seatainer Terminals Pty Ltd (1981) 48 LGRA 409 at 434; Maurici at 116 [8].
53 There can be no doubt that Mr Jackson's improved sales prima facie afforded some evidence of value. They were rejected by the primary judge as unreliable (which I do not distinguish from irrelevant) on the basis that, for high rise office buildings, the adoption of a single depreciation rate for the improvements was too simplistic and would not enable an "accurate assessment" of the unimproved land value to be derived. The effect of this rejection was that given his rejection of the historic land sales, his Honour was left with only one sale for comparison purposes, namely, 232-248 Pitt Street.
54 As a matter of valuation practice, and as Rost & Collins make clear, the assessment by a valuer of an appropriate depreciation rate is a matter of judgment based on his or her experience and supported by such tests as may be practicable. As Stein JA, with whom Priestley JA and Sheppard A-JA agreed, observed in Hornsby Shire Council v Roads & Traffic Authority of New South Wales (1998) 100 LGERA 105 at 108-9, the judicial valuer and, for that matter any valuer, is required to make inferences and apply experience and judgment in order to determine what are really hypothetical questions. These questions may involve subjective judgments and must inevitably leave room for differences of opinion.
55 In the present case, there was no doubt as to Mr Jackson's experience in valuing improved and unimproved CBD land. It may well be that, theoretically at least, Mr Hill was correct when he said, and the primary judge accepted, that for an accurate assessment to be made, separate depreciation rates should be applied to the 40 or 50 components of a high rise office building. But such an approach would be a counsel of perfection. It would not, in the type of valuation exercise Mr Jackson was required to undertake, be practicable in the sense in which Rost & Collins employ that term.
56 It is trite to say that valuing property is not an exact science. Obviously, the valuer must attempt to be as accurate as is practicable. In determining a single depreciation rate for a high-rise building, the valuer would no doubt take into account that the building does comprise many components whose residual life will differ. There is nothing in the evidence to which our attention was drawn to suggest that Mr Jackson did not, in adopting his depreciation rate for the improvements in each sale, take that factor into account.
57 In these circumstances, and particularly given the scarcity of comparable vacant land sales (there was only one found by his Honour to be comparable), it was in my respectful opinion both contrary to valuation principle and irrational for the primary judge to reject Mr Jackson's improved sales upon the ground that the adoption by him of a single depreciation rate was too simplistic to enable those sales to be regarded as "some evidence of value".
58 Furthermore, having rejected the historic land sales, his Honour undermined what I regard as the essential foundation upon which Mr Hill rejected Mr Jackson's adoption of a single depreciation rate for his improved sales, namely, that there were other and more reliable sales upon which to rely. In accepting Mr Hill's evidence identified by him in [67] of his judgment, his Honour misunderstood at least one of the bases upon which Mr Hill had rejected Mr Jackson's valuation approach. On my understanding of his Honour's acceptance of Mr Hill, he treated him as saying that a valuer can never apply a simple depreciation rate to the cost of improvements to derive land value when Mr Hill did not say that. If he did, it would be wrong as a matter of established valuation principle when analysing improved sales. For the foregoing reasons I therefore consider that his Honour erred in law in rejecting outright Mr Jackson's approach to the depreciation of the improvements upon the land the subject of the sales upon which he relied.