Perrett v Commissioner for Superannuation

[1991] FCA 361

Re: CHRISTINE PERRETT
And: COMMISSIONER FOR SUPERANNUATION
No. V G196 of 1990
FED No. 361
Superannuation
29 FCR 581/13 AAR 440
23 ALD 257
(1991) 40 IR 169

COURT

IN THE FEDERAL COURT OF AUSTRALIA

VICTORIA DISTRICT REGISTRY
GENERAL DIVISION
Wilcox(1), Burchett(1) and Ryan(1) JJ.

CATCHWORDS

Superannuation - Certificate by medical practitioner that employee suffering from psoriasis - Employee subsequently retired on ground of invalidity, the relevant invalidity being occasioned by psoriatic arthritis - Whether psoriatic arthritis was "connected with" psoriasis, there being no known causal connection between the two conditions - Whether the words "connected with" postulate a causal relationship - Nature of connection between two conditions.

Superannuation Act 1976, s.66(2)

HEARING

MELBOURNE

#DATE 24:5:1991

Counsel for the Applicant: R. Gorton, QC and T. Tobin

Solicitors for the Applicant: Slater and Gordon

Counsel for the Respondent: J. Karkar, QC and R. Tracey

Solicitors for the Respondent: Australian Government Solicitor

ORDER

The appeal be dismissed.

Note: Settlement and entry of orders is dealt with in Order 36 of the Federal Court Rules. (See also Order 37 rule 2(3)).

JUDGE1

This is an application by way of appeal pursuant to s.44 of the Administrative Appeals Tribunal Act 1975 against a decision of the Tribunal affirming a decision of the Commissioner for Superannuation concerning the operation of s.66(2) of the Superannuation Act 1976. Normally, the appeal would have been heard by a single Judge of the Court but the appellant wished to call into question aspects of a decision made by Jenkinson J. at an earlier stage of the dispute between the parties: see Commissioner for Superannuation v Perrett (1989) 23 FCR 425. Accordingly, Northrop J. directed that the matter be listed before a Full Court.

The background facts

1. The appellant, Christine Perrett, was born in 1948. Since the age of about 15 years she has suffered from a skin condition which was diagnosed, some years after its first appearance, as psoriasis. In 1969, Mrs Perrett joined the Postmaster General's Department, as it then was, as a telephonist. She received a permanent appointment in the Department in 1974. In January 1975 Mrs Perrett underwent a medical examination for the purposes of the Superannuation Act 1922. In his report of the medical examination, the examining medical officer referred to her psoriasis but nonetheless recommended that she be accepted for the Provident Account established under that Act.

2. In 1976 the earlier Act was replaced by the Superannuation Act 1976. The new Act conferred benefits on those persons who fell within its definition of "eligible employee". They included Mrs Perrett: see paras.(a) and (b) of the definition contained in s.3.

3. Section 16 of the 1976 Act relates to medical examinations and benefit classification certificates. It authorises the Commissioner for Superannuation to require a person who proposes to become, or who becomes, an eligible employee to undergo such medical examination or examinations as the Commissioner determines. Subsection (4) provides:
   

"(4) The Commissioner shall consider the report or reports, and such other matters (if any) as the Commissioner considers relevant, and, if he is of the opinion that there is a real risk that the person, by reason of or for a reason connected with a physical or mental condition or conditions referred to in the report or reports, will not continue to be an eligible employee until the person attains his maximum retiring age, the Commissioner shall issue a benefit classification certificate to that effect, being a certificate in which the relevant condition or conditions is or are specified."

1. The section goes on to provide for the reconsideration and revocation of benefit classification certificates. Moreover, by subs.(5) such a certificate loses its effect where the eligible employee has not less than 20 years contributory service or attains the maximum retiring age. But, in other circumstances, whilst the certificate stands, it may significantly reduce the entitlements of a contributor. This is because of s.66(2), which provides a lower scale of invalidity benefits - subject to certain presently irrelevant provisions - in respect of persons who fall within each of paras.(a), (b) and (c) of that subsection. Section 66(2) reads:
   "Subject to sub-sections (3), (3A) and (4) of this section and section 79, where-
   (a) a person ceases to be an eligible employee by reason of retirement
   

on the ground of invalidity before attaining his maximum retiring age;

(b) there was in force in respect of the person, immediately before

the person's retirement, a benefit classification certificate; and

(c) the Commissioner is of the opinion that the incapacity which was

the ground for his retirement was caused, or was substantially contributed to, by a physical or mental condition or conditions specified in the certificate or by a physical or mental condition or conditions connected with such a condition or such conditions,

the person is entitled -

(d) where the period of contributory service of the person is not less

than 8 years -

(i) if the person does not make an election under section 71 or 72 - to invalidity pension in accordance with section 70 and, where the person has paid supplementary contributions, a lump sum benefit in accordance with that section;

(ii) if the person makes an election under section 71 - to invalidity pension, and a lump sum benefit, in accordance with that section; or

(iii) if the person is entitled to make an election under section 72 and makes such an election - to a lump sum benefit in accordance with that section; or

(e) where the period of contributory service of the person is less

than 8 years - to a lump sum benefit in accordance with section 73."

1. As we have indicated, Mrs Perrett's medical examination preceded the 1976 Act. It was not undertaken pursuant to s.16. But Part XII of the 1976 Act contained transitional provisions. They included s.184(3) which empowered the Commissioner to "issue in respect of the eligible employee a benefit classification certificate in which the physical or mental condition or conditions of the person that was or were relevant for the purposes of the superseded Act (that is, the 1922 Act) is or are specified and, for the purpose of this Act, the certificate shall be deemed to have been issued under subsection 16(4)."

2. In April 1985, pursuant to s.184(3), the Commissioner issued a benefit classification certificate specifying psoriasis. Mrs Perrett has not challenged that certificate, either on the basis that the Commissioner was not authorised by the legislation to issue it, or on the basis that the material said to justify it did not really do so.

3. In June 1985, Mrs Perrett was again medically examined. The examining medical officer noted her complaints of pain and swelling of her joints, especially continuous pain in her hands and feet. He recommended that she be retired on the ground of invalidity.

4. The medical officer's recommendation was accepted, with effect from 28 June 1985. This date was well before she would have attained her maximum retiring age. Accordingly, para.(a) of s.66(2) was satisfied. Moreover, the benefit classification certificate remained in force; para.(b) applied. But there was a question about the application of para.(c).

5. The Commissioner formed the opinion that para.(c) did apply. Apparently nobody suggested that the incapacity which led to Mrs Perrett's retirement, the pain and swelling in her joints, was caused, or substantially contributed to, by psoriasis. But the Commissioner was of the opinion that the incapacity was caused by a physical condition "connected with" psoriasis; namely, psoriatic arthritis. Accordingly, he applied s.66(2); thus remitting Mrs Perrett to the lesser benefits provided by that subsection.

6. Mrs Perrett challenged this decision before the Administrative Appeals Tribunal. The persons who constituted the Tribunal for the purposes of that appeal were the same three people as those from whom the present appeal is brought.

7. The Tribunal heard evidence from two specialist rheumatologists, one called by each of the parties. There was a substantial measure of agreement between them. In its reasons for decision given on 24 August 1989 the Tribunal said:
   "13. Dr Harkness has been Mrs Perrett's treating specialist since
   

October 1984. He has practised as a specialist rheumatologist since 1974, and is concerned in the training of medical students in this area. Dr Webb has practised as a specialist rheumatologist since

1959. They each referred the Tribunal to authoritative medical publications. They agreed, and the Tribunal finds, that the cause of psoriasis is unknown, and the cause of psoriatic arthritis is unknown; that people who suffer from psoriasis may develop arthritis of a particular kind, which is easily recognisable on clinical examination, and is known as psoriatic arthritis; that some people without a previous history of psoriasis develop psoriatic arthritis, and in such people it is described as 'psoriatic arthritis sine psoriasis'; and that of these people, some subsequently develop psoriasis, and some do not.

14. Dr Harkness said that, on his reading of the authorities, the

percentage of people with psoriasis who developed psoriatic arthritis was about 4 per cent; only very slightly more than the percentage of people in the general population who develop arthritis of one kind or another. There was a strong association between psoriasis and psoriatic arthritis, but nothing was known about the causation of either.

15. Dr Webb was of the view that the authorities indicated that

approximately 10 per cent of people with psoriasis would develop psoriatic arthritis. There might be a causal connection between psoriasis and psoriatic arthritis, but there was no evidence on which that could be said. It was a possibility, not a probability. The distinction between psoriatic arthritis and rheumatoid arthritis was at the level of the clinical picture only, not some underlying process which could be distinguished on examination at the cellular level. He agreed that the statistical relationship was not of assistance in the context of ascertainment of a causal relationship except insofar as it raised questions."

1. The Tribunal concluded that there was no evidence before it to indicate "more than the possibility of a causal connection between psoriasis and psoriatic arthritis". Interpreting Commissioner for Superannuation v Miller (1985) 8 FCR 153 as a decision that the words "connected with" in s.66(2)(c) referred to a causal relationship, the Tribunal concluded that para.(c) did not apply. Mrs Perrett's appeal was upheld.

2. The Commissioner for Superannuation appealed against this first decision of the Tribunal, contending that the Tribunal had misunderstood Miller. The appeal came before Jenkinson J. and was upheld. The Commissioner's argument was assisted by the circumstance that, between the time of the Tribunal's first decision and the hearing before Jenkinson J., a Full Court (Morling, Beaumont and Burchett JJ.) had heard and determined Commissioner for Superannuation v Benham (1989) 22 FCR 413. In that case, the Full Court analysed and explained the judgments in Miller. The Court rejected the view that "connected with" imported the notion of causality. But it also emphasised the significance of the word "substantial". At pp 420-421 their Honours said:
   

"There is no difficulty on this view, with the word 'substantial'. The context demands nothing less. For s.66(2) is concerned with depriving a retired employee of a benefit paid for by a contribution proportionately equal to that made by other eligible employees. Having a certified condition, she is thought to be in a situation requiring a diminution of benefit if early retirement is caused or contributed to by that condition. So much protection the fund requires in return for her statutory eligibility. It is easy, too, to comprehend that the legislature may have considered the protection inadequate should retirement be produced by a condition not expressly mentioned in the certificate, but either arising out of it sufficiently proximately (as in Miller), or forming part of a wider condition sufficiently closely involving the certified condition (as postulated by Pincus J.). There may be other examples, but there is nothing to suggest an insubstantial connection was contemplated as the basis for depriving a retired employee of benefits. That would be unnecessary. If the connection is insubstantial, the risk of such a condition befalling the particular employee cannot have been significantly greater than in the case of employees generally. Only a necessary protection of the fund could justify taking away from the retired employee a portion of her full benefit where the incapacity does not flow from a certified condition. This is, after all, beneficial legislation to which the 'established principle' mentioned by Fullagar J. in Wilson v Wilson's Tile Works Pty Ltd (1960) 104 CLR 328 at 335 applies, as it does in relation to a Workers' Compensation Act, that 'where two constructions ... are possible that which is favourable to the

(employee) should be preferred.' ... The construction which should be adopted, in the case of this Act, is a reading of s.66(2)(c) as referring to cases where there is a real and substantial connection between the certified condition and the condition that caused or substantially contributed to the incapacity."

1. Jenkinson J. applied Benham and held that the first Tribunal was erroneous in law. He observed, at p 427:
   

"It has been accepted by the parties and by the Tribunal that the incapacity which was the ground for the respondent's retirement was caused by a physical condition which is designated psoriatic arthritis in medical nomenclature. It has also been accepted by the parties and by the Tribunal that, notwithstanding that suggestive name, the evidence did not justify a finding that the respondent's incapacity was - or, generally, that the condition known as psoriatic arthritis is - caused, or contributed to, by psoriasis. The Tribunal was concerned, as is the court in this appeal, with the question whether psoriatic arthritis is `connected with' psoriasis in the sense in which that expression is, on the proper construction of s.66(2)(c), to be understood.

The evidence before the Tribunal in my opinion required, and the Tribunal in fact made, the findings which the Tribunal thus expressed: `that the cause of psoriasis is unknown, and the cause of psoriatic arthritis is unknown; that people who suffer from psoriasis may develop arthritis of a particular kind, which is easily recognisable on clinical examination, and is known as psoriatic arthritis; that some people without a previous history of psoriasis develop psoriatic arthritis, and in such people it is described as "psoriatic arthritis sine psoriasis"; and that of these people, some subsequently develop psoriasis, and some do not.' Further, the particularity to which reference is made by the Tribunal in the passage quoted consists merely of clinically obvious or radiographically demonstrable signs and characteristic symptoms, the evidence showed, not of any biological or chemical singularity. The Tribunal had no evidence - and did not find - that the psoriatic arthritis was caused by the psoriasis or that psoriasis substantially contributed to the development of the psoriatic arthritis. Mr Tracey of counsel for the applicant Commissioner did not submit that the Tribunal had erred in failing to reach either of those factual conclusions. His case was that a causal relationship between specified condition and incapacitating condition was not the only relationship which could satisfy the words `connected with' in s.66(2)(c). It was the understandable belief of the members of the Tribunal that the reasoning of two members of a Full Court of this Court in Commissioner for Superannuation v Miller (1985) 8 FCR 153, Davies and Pincus JJ., had established that only if the condition specified in the certificate had contributed to cause the incapacitating condition was the latter condition `connected with' the former. However, after the Tribunal's decision had been given, another Full Court of this Court, in Commissioner for Superannuation v Benham (1989) 22 FCR 413, observed of the judgment of the third member of the court in Miller's case (supra), Beaumont J.: `His appears to us to be the majority view, since Davies J., while adding the comments to which reference has been made, expressed general agreement with it.' Beaumont J. had in Miller's case (supra), expressly refrained from asserting that the relationship required by the words `connected with' must necessarily be causal, as the Full Court pointed out in Benham's case (supra)."

1. After setting out a passage from the judgment of Beaumont J. in Miller, his Honour went on to note (at p 428):
   

"In both Miller's case and Benham's case the only connection suggested between the condition specified in the certificate and the incapacitating condition was a causal connection. I understand the Full Court in Benham's case to have denied ... that Miller's case provided authority for the proposition that only a causal connection could satisfy the requirement of s.66(2)(c) that the incapacitating condition, if it were not a specified condition, should be connected with a specified condition. The question then is whether in Benham's case itself authority for or against that proposition is to be found."

1. Jenkinson J. then referred to various sub-sections of s.16 of the Superannuation Act and set out in full the reasoning of Davies J. in Miller. With that introduction his Honour referred to the conceptual difference between the reasoning of Davies J. in Miller and that of Pincus J. in the same case which was identified by the Full Court in Benham. At p 431, Jenkinson J. expressed his own analysis of the approach favoured by Pincus J.:
   

"It would seem that for Pincus J. it is enough that each condition - the specified and the incapacitating - is an effect of the same cause. If that be so, the words `connected with' in s66(2)(c) may be satisfied without any causal contribution to the existence of the incapacitating condition by the specified condition."

1. His Honour reproduced the passage from the judgment of the Full Court in Benham which we have set out above. He continued at pp 431-432:
   

"I am not certain whether the reference in that passage to what is there said to have been postulated by Pincus J. amounts to an expression of approval of the view Pincus J. had expressed, or merely forms part of a parenthetical concession that `the legislature may have', not that it had, intended what Pincus J. expounded concerning s66(2)(c). If the latter be the correct understanding of the reference, the final sentence of the passage last quoted from the Full Court's reasons in Benham's case cannot be understood as going further than to insist that the connection contemplated by s66(2)(c) must be `real and substantial'. If the former be the correct understanding of the reference, the Full Court's approval of the view Pincus J. had expressed is in my opinion necessarily approval of the proposition that the words `connected with' in s66(2)(c) comprehend a relationship between certified condition and incapacitating condition other than that of cause and effect. Whatever the Full Court in Benham's case ought to be taken to indicate by the phrase `a condition not expressly mentioned in the certificate, but ... forming part of a wider condition sufficiently closely involving the certified condition', Pincus J. in plain terms says that there may be `a substantial link' between incapacitating condition and specified condition - and therefore in his opinion a connection between them satisfying s66(2)(c) - `because both have a common cause', that is to say each is an effect of the same cause."

1. Jenkinson J. then considered for himself the question whether s.66(2)(c) can be satisfied only if the incapacitating condition either is, or is caused by, the specified condition. He prefaced this consideration with the words: "Supposing myself, but doubtfully, without authoritative guidance" upon the question. At pp 433-434 he expressed his conclusion in this way:
   

"In my opinion the expression `connected with' in s66(2)(c) does comprehend, on the proper construction of the paragraph, something short of the relationship between cause and effect. The choice of that expression by the draftsman strongly suggests that something more comprehensive than a causal relationship was to be indicated, for there is no shortage of stock expressions for denoting a causal relationship in the phrase book of legislative drafting, and `connected with' is not one of them. I respectfully agree in the opinion Beaumont J. expressed in Miller's case that `connected with' is intended to have in s66(2)(c) its ordinary meaning, and that that meaning comprehends `those cases where a link or an association exists between two medical conditions'. In my opinion such a link or association might be constituted by a higher incidence, in a community, of a medical condition among those of the community in whom another medical condition is known to exist than among the rest of that community. Unless the one were distinctly higher than the other the requirement that the connection be `substantial', upon which the Full Court insisted in Benham's case, would no doubt not be satisfied. If the disparity of incidence were explained by the circumstance that those in whom the other condition is known to exist are more frequently or more thoroughly subjected to procedures calculated to disclose the existence of the condition first mentioned than are other members of the community, that might lead to the conclusion that the connection was not `real', in the sense I take to have been intended by the Full Court in Benham's case, and that the two conditions were not linked in what Beaumont J. in Miller's case called `a relevant medical sense'. What may be an association in a relevant medical sense will depend largely on facts, which it would be unwise to attempt to classify. I apprehend that the connection will be neither `real' nor `substantial' unless the disparity of incidence justifies an inference that the risk of suffering the condition which incapacitated the eligible employee is substantially greater for those who suffer the specified condition than it is for the rest of the community. There was evidence before the Tribunal to suggest a disparity of incidence of the kind which might justify a finding of the required connection, for the purposes of s66(2)(c). The incidence of psoriatic arthritis among those known to be, or to have been, suffering psoriasis is, according to the evidence, higher than among those who have been free of psoriasis. The Tribunal noted the evidence, but put it aside because it did not satisfy what the Tribunal took to be the requirement of s66(2)(c) that the specified condition should have contributed to cause the incapacitating condition. Counsel for the parties were agreed that, if an order were made remitting the case to be heard and decided again, there should be an order authorising the reception of further evidence. I agree. There is no warrant for any direction by me with respect to the evidence or to facts the finding of which the evidence might justify. The applicant Commissioner challenged only the construction which the Tribunal had placed on the words `connected with' in s66(2)(c). For the reasons I have stated, I consider that construction to have been erroneous."

1. Jenkinson J. set aside the Tribunal's first decision and remitted the matter to the Tribunal, with leave to receive further evidence. As already noted, at the rehearing the Tribunal was constituted by the same three persons. Some additional medical evidence was tendered. On 13 June 1990 the Tribunal gave its second decision, the decision the correctness of which in point of law is the question in the present appeal. Mrs Balmford and Professor Webster incorporated in their joint reasons for decision some of what the Tribunal had said previously:
   "9. In the present case the incapacity apparent from Dr McInnes'
   

report was continuous pain in the hands and feet. That was ... `the outward result' that led to Mrs Perrett's `being unable to perform ... (her) duties'. As we have found, the decision to retire Mrs Perrett was based on Dr McInnes' report. Thus we find that the incapacity which was the ground of Mrs Perrett's retirement, in terms of paragraph 66(2)(c) of the Act, was continuous pain in the hands and feet.

1. The next question is whether, in terms of paragraph 66(2)(c),

that incapacity was caused or was substantially contributed to by the condition `psoriasis'... or by a physical or mental condition connected with the condition `psoriasis'.

1. It was not suggested that the incapacity in question was cau

sed or was substantially contributed to by the condition psoriasis. The submission of the respondent, however, was that the incapacity was caused or was substantially contributed to by a physical or mental condition connected with the condition psoriasis.

1. In his report, under the heading `I consider that the examin

ee is suffering from the following medical condition(s) (in order of severity) and with estimated percentage each contributes to the incapacity', Dr McInnes wrote `Rheumatoid arthritis 100 per cent'. However, after obtaining reports from Dr Webb and Dr Harkness, he formed the opinion that the correct description of the condition was `psoriatic arthritis'.

1. Dr Harkness has been Mrs Perrett's treating specialist since

October 1984. He has practised as a specialist rheumatologist since 1974, and is concerned in the training of medical students in this area. Dr Webb has practised as a specialist rheumatologist since 1959. They each referred the Tribunal to authoritative medical publications. They agreed, and the Tribunal finds, that the cause of psoriasis is unknown, and the cause of psoriatic arthritis is unknown; that people who suffer from psoriasis may develop arthritis of a particular kind, which is easily recognisable on clinical examination, and is known as psoriatic arthritis; that some people without a previous history of psoriasis develop psoriatic arthritis, and in such people it is described as `psoriatic arthritis sine psoriasis'; and that of these people, some subsequently develop psoriasis, and some do not.

1. Dr Harkness said that, on his reading of the authorities, the

e percentage of people with psoriasis who developed psoriatic arthritis was about 4 per cent; only very slightly more than the percentage of people in the general population who develop arthritis of one kind or another. There was a strong association between psoriasis and psoriatic arthritis, but nothing was known about the causation of either.

1. Dr Webb was of the view that the authorities indicated that

approximately 10 per cent of people with psoriasis would develop psoriatic arthritis. There might be a causal connection between psoriasis and psoriatic arthritis, but there was no evidence on which that could be said. It was a possibility, not a probability. The distinction between psoriatic arthritis and rheumatoid arthritis was at the level of the clinical picture only, not some underlying process which could be distinguished on examination at the cellular level. He agreed that the statistical relationship was not of assistance in the context of ascertainment of a causal relationship except insofar as it raised questions. ...

1. ... No evidence before us in the present case indicated more

than the possibility of a causal connection between psoriasis and psoriatic arthritis."

1. The joint reasons then reproduced the last extract which we have quoted from Jenkinson J.'s judgment, adding emphasis to certain passages, and continued:
   "9. It was not suggested at the resumed hearing that any of the findings
   

of fact at the original hearing were incorrect, out of date, or should for any other reason be reconsidered. ...

1. Dr Harkness said in evidence that he had seen Mrs Perrett three

times since he gave evidence in this matter in 1988. There was no change in diagnosis or prognosis. The following passage appears in the transcript of his examination-in-chief:

`Now, the condition that Mrs Perrett suffers from, what do you class that condition as?---She has psoriatic arthritis. Are there various forms of psoriatic arthritis?---Yes, it is very much as you outlined in your introductory comments, the five different types.

Right. And of those five different types what type does she have?- --She has a polyarticular form.'

and the following in the transcript of his cross-examination: `... you said that right from the first you diagnosed Mrs Perrett as having psoriatic arthritis?---In 1984, yes. And do you agree that psoriatic arthritis is now regarded as a separate true entity?---Separate true entity. Five, separate true entities.

Yes. You mean there are five separate types, that is psoriatic arthritis?---Recognisably different sub-types of psoriatic arthritis.'

1. He said that approximately 5 per cent of people with psoriasis

develop psoriatic arthritis. The earlier literature gives higher percentages, largely because the earlier work was done on hospital patients. Of those 5 per cent, 15 per cent develop the polyarticular form ("polyarthritis"). Thus Mrs Perrett is one of the .75 per cent of people with psoriasis who develop polyarthritis. Assuming the incidence of psoriasis in the general community to be 5 per cent, the percentage of the general community who develop psoriatic arthritis would be extremely small. A few people without psoriasis develop psoriatic arthritis: in his practice he would certainly see a case every year, but not every month.

1. Dr Clarke said in evidence that it was his understanding from

the literature that 7-10 per cent of people with psoriasis developed psoriatic arthritis, but only .14 per cent of the general community did so.

1. Dr Webb confirmed the statement in his report that Mrs Perrett

was `one of the 10 per cent of patients suffering from psoriasis who in fact develop arthritis'. In that report he went on to say `I would find it very hard, however, to classify her arthritis in any way other than psoriatic arthritis'. A diagnosis of psoriatic arthritis in a person without psoriasis involved a confident expectation that the patient would one day, perhaps not for many years, develop psoriasis. If that did not happen, either the diagnosis was wrong, or the patient had died before the inevitable psoriasis appeared.

1. In his report of 17 June 1990 Dr Kemp said of Mrs Perrett:

`In my opinion there is no doubt that she has psoriatic arthritis which is a sero-negative inflammatory polyarthritis similar to rheumatoid disease, but with a clinical association with psoriasis of the skin and nails.'

In his report of 14 March 1990 he said that about 10 per cent of those with psoriasis developed psoriatic arthritis and there was a .2 per cent prevalence of psoriatic arthritis in the general community. By definition there was no incidence of psoriatic arthritis in those of the community who did not suffer from psoriasis. In evidence he said that the whole subject was imprecise, because, unless the patient complained of a skin rash, rheumatologists would look for skin lesions, but many other doctors would not.

1. The authors of the joint reasons then referred to consensus among the rheumatologists who gave evidence" that:
   

"a person who has both psoriasis and

polyarthritis has a better prognosis, so far as the incapacitating effects of the arthritis are concerned, than a person who has polyarthritis without psoriasis. If the arthritic condition from which Mrs Perrett suffers were to be

characterised as inflammatory polyarthritis it could be seen, on that basis, that her risk of becoming incapacitated from that condition was less than it would have been had she not

suffered from psoriasis."

They went on:

"16. However, ... that submission confuses the issue with which we

are here concerned with another issue with which we are not concerned. We are concerned to determine whether the arthritic condition which incapacitated Mrs Perrett is `connected with' her condition of psoriasis. In that context, the judgment of Jenkinson J. in this matter leads us to consider whether the risk of suffering that arthritic condition is substantially greater for a person with psoriasis than for the rest of the community. We are not concerned to determine whether or not the risk of a person with any arthritic condition becoming incapacitated is greater in a person with psoriasis than in the rest of the community. Questions relating to the risk of incapacity are highly relevant to the administration of the Act, but no such question is before us here.

1. Mr Tobin (counsel for Mrs Perrett) submitted further that, on

the evidence, a person with psoriasis had no greater risk of developing inflammatory polyarthritis than a member of the general community. Therefore, if Mrs Perrett's arthritic condition was characterised as inflammatory polyarthritis, it could not be said to be `connected with' her condition of psoriasis in terms of the test enunciated by Jenkinson J. However, the evidence of the three rheumatologists, including Mrs Perrett's treating doctor, was unanimous that the condition from which she is suffering is, as the Tribunal found at the original hearing, properly described as `psoriatic arthritis'.

1. That being so, it is clear from the evidence set out in parag

raphs 10-14 supra that there is a disparity of incidence of psoriatic arthritis between people with psoriasis on the one hand and the general community on the other. It is not necessary for us to reconcile the various statements before us as to the precise extent of that disparity. We are satisfied on the evidence, and we find, that, in terms of Jenkinson J.'s criterion cited in paragraph 8 supra, `the disparity of incidence justifies an inference that the risk of suffering the condition which incapacitated the eligible employee is substantially greater for those who suffer the specified condition than it is for the rest of the community'.

1. We are accordingly satisfied, and we find, that the incapacity

which was the ground of Mrs Perrett's retirement was caused or was substantially contributed to by a condition connected with the condition specified in the benefit classification certificate that was in force in respect of her immediately before her retirement. For the reasons given, the decision under review will be affirmed."

The need for a causal relationship

1. As we have indicated, Mrs Perrett challenges before us the correctness of the judgment of Jenkinson J. which underlay this second Tribunal decision. The challenge goes to the central question decided by his Honour: whether the words "connected with" import a requirement of a causal relationship between the certified condition and that causing the employee's retirement. Counsel for Mrs Perrett submit that such a relationship is necessary; that is, that the certified condition must be a cause of, or factor in the development of, the incapacitating condition. In support of that submission they refer to the terms of s.16, especially s.16(4). They question whether the decision in Benham reflected a correct analysis of Miller and they emphasise the disadvantage to an employee of the application of s.66(2). They point also to the likely difficulty, in many cases, of determining the limit of the relevant connection, once the requirement of causation is abandoned.

2. We appreciate the force of all these matters but it seems to us too late to reopen the issue of causality. Whether or not their reasoning inevitably flowed from Miller, the members of the Full Court, in Benham, clearly rejected the argument that the words "connected with" required a causal relationship between the two conditions. Even the High Court, which, as a final court of appeal, is in a special position, will "not lightly" depart from its previous decisions: John v Commissioner of Taxation of the Commonwealth of Australia (1989) 166 CLR 417 at p 438. In this Court, it has been said that "exceptional circumstances" are required: Bradley v Armstrong (1981) 39 ALR 118 at pp 119, 124; and see Wood v City of Melbourne Corporation (1979) 26 ALR 449. Moreover, the natural meaning of the words "connected with" strongly suggests the view the Full Court adopted. As Jenkinson J. pointed out, had the draftsman intended to confine the operation of s.66(2)(c) to cases where there was a causal relationship between the two conditions, there would have been no difficulty in saying so in unambiguous terms. Yet there was chosen a phrase of wide connotation which merely requires a relation between one thing and another: see Our Town FM Pty Ltd v Australian Broadcasting Tribunal (1987) 16 FCR 465 at pp 479-480 and the cases there cited. It seems to us that the conclusion expressed by the Full Court in Benham, and by Jenkinson J. in this case, was correct. The Tribunal was correct in holding that psoriatic arthritis might be connected with psoriasis notwithstanding the lack of any causal relationship between the two conditions.
   The connection between psoriasis and psoriatic arthritis

3. By way of alternative submission, counsel for Mrs Perrett contend that, even if a causal relationship is not required, there was not in this case evidence to permit the Tribunal to find the existence of a connection between psoriasis and psoriatic arthritis. It is not enough, say counsel, to find that psoriatic arthritis is more prevalent amongst sufferers of psoriasis than in the general community. Counsel contend that the Tribunal did not go beyond a consideration of whether the statistical evidence permitted an inference of connection to be drawn; and, in particular, did not decide what inference to draw. Accordingly, say counsel, the Tribunal did not discharge its function and the case should again be remitted so that they might do so.

4. In support of this aspect of their submissions counsel for Mrs Perrett referred to a decision of the Full Court of the Supreme Court of Victoria, Dahl v Grice (1981) VR 513. That was a personal injuries negligence claim, one question being whether it was open to the jury to find a causal connection between the apparently mild head injuries suffered by the respondent at the time of the accident and a cerebral aneurysm which occurred some 14 weeks later. Gobbo J., with whom Young C.J. and Kaye J. agreed, discussed the problems involved in inferring causation, in a medical context, at p 523. During the course of that discussion, his Honour quoted and adopted certain statements of Mahoney J.A. in Fernandez v Tubemakers of Australia Ltd (1975) NSWLR 190. One of those statements, particularly relied on by counsel in the present case, was summarised by Gobbo J. in this way:
   

"At p 200 his Honour rejected any suggestion that the step from possible to actual cause was simply 'intuitive' and subject to no limitations. Rather the question was 'whether the evidence showed the connection between the possible cause and the condition which occurred was sufficiently close to warrant a reasonable mind, faced with the problem of determining the question upon the evidence before it, concluding that the possible was the actual cause."

Gobbo J. went on to apply that test in the Victorian case.

1. Dahl v Grice involved a question of causation, a question which does not necessarily arise under s.66(2)(c). As we have indicated, there may be a connection for the purposes of that paragraph which falls short of a causal relationship. But, of course, the application of s.66(2)(c) involves a similar need to examine the evidence closely, in any particular case, to determine whether there is a sufficient relationship between a certified condition and an incapacitating condition for it to be concluded that the one is "connected with" the other.

2. The evidence before the Tribunal included some statistical material. The experts gave varying percentages of psoriasis sufferers who developed psoriatic arthritis; they ranged from Dr Harkness' estimate of approximately 5% through Dr Clarke's 7 to 10% to Dr Webb's figure of 10%. True it is, as counsel for Mrs Perrett emphasised, that, upon any of these figures, the overwhelming majority of people who suffer from psoriasis do not contract psoriatic arthritis; but nonetheless, the proportion who do so greatly exceeds the minute proportion (0.14%) of non-psoriasis sufferers who develop the condition.

3. However, suggestive though this evidence is, standing alone it would not be enough to establish the connection contemplated by s.66(2)(c). There is always a possibility that people who suffer from one particular physical condition will be disproportionately represented amongst sufferers of another, medically unrelated, condition; perhaps because of geographic, ethnic or lifestyle factors.

4. In the present case there was evidence of a medical connection. Although none of the medical experts was able to describe any causal connection between the two conditions, Dr Harkness, Dr Webb and Dr Kemp all referred to the existence of an "association" between the two conditions. Each of them said that the type of arthritis developed by psoriasis sufferers is clinically distinct from other types of arthritis. Particularly important was the evidence that most people who have psoriatic arthritis already suffer from psoriasis. Some psoriatic arthritis sufferers do not have psoriasis. In this case the condition is called "psoriatic arthritis sine psoriasis", the name perhaps emphasising the unusual nature of this situation. But, even then, there is an expectation that psoriasis will develop. Dr Webb put the matter in this way in the course of his evidence: "... you probably could not say that every patient in whom you may initially make the diagnosis of psoriatic arthritis without psoriasis will in the end develop psoriasis. The majority will, but some will do other things."

5. It is obvious from the evidence that there are still major gaps in medical scientists' knowledge of psoriasis and psoriatic arthritis. But there was material before the Tribunal which, as a matter of law, enabled it to conclude that there was a connection within the meaning of s.66(2)(c).

6. The appellant contended that the Tribunal did not weigh the evidence in order to apply the law as stated in Benham, but applied too narrow a view, taking a statistical comparison as a determinant. We do not think the Tribunal's reasons, read as a whole, really disclose such an error. In any case, the Tribunal has found the facts very fully, and, on its findings, the ultimate conclusion to which it came is quite inescapable. Accordingly, the appeal must be dismissed.

7. When the previous appeal was determined by Jenkinson J. apparently no order was made in respect of costs. We propose to make no costs order in the present case. The Tribunal has no power to make orders for costs in relation to cases of this nature and it seems to us to be undesirable that persons who unsuccessfully challenge a decision of the Tribunal should automatically be visited with a costs order in this Court. The Court should consider the matter of costs, bearing in mind the result of the appeal but also taking into account the reasonableness of the applicant in bringing that appeal and the general importance of the clarification of the law for such an authority as the respondent. We think that this appeal was reasonably brought. As is evident from the number of occasions upon which s.66(2)(c) has been considered by Full Courts, the paragraph presents difficulties of interpretation. In the present case, involving as it does two physical conditions about which much remains to be learned, it also presents difficulties of application.