Australian Pork Ltd v Director of Animal & Plant Quarantine - [2005] FCA 671

FEDERAL COURT OF AUSTRALIA
Australian Pork Ltd v Director of Animal & Plant Quarantine [2005] FCA 671
ADMINISTRATIVE LAW – Quarantine – Importation of pig meat – Report of expert committee for the purpose of enabling the Director of Animal and Plant Quarantine to formulate a general policy for application by decision-makers in relation to applications for import permits – Director decided to adopt the committee’s recommended control measures as general policy – Challenge by Australian pig meat producers to legal validity of recommendations – Challenge to one particular import permit decision made in reliance upon the general policy – Whether either or both decisions were invalid for error of law, failure to take into account a relevant consideration, unreasonableness or absence of evidence.
Quarantine Act 1908 (Cth) ss 4, 5, 5D, 13
Quarantine Proclamation 1998 (Cth) cll 39, 70
AUSTRALIAN PORK LIMITED and WINDRIDGE FARMS PTY LIMITED v DIRECTOR OF ANIMAL AND PLANT QUARANTINE and FAYMAN INTERNATIONAL PTY LIMITED
NSD 1078 of 2004
WILCOX J
27 MAY 2005
SYDNEY

IN THE FEDERAL COURT OF AUSTRALIA

NEW SOUTH WALES DISTRICT REGISTRY

NSD 1078 of 2004

BETWEEN:

AUSTRALIAN PORK LIMITED
FIRST APPLICANT

WINDRIDGE FARMS PTY LIMITED
SECOND APPLICANT

AND:

DIRECTOR OF ANIMAL AND PLANT QUARANTINE
FIRST RESPONDENT

FAYMAN INTERNATIONAL PTY LIMITED
SECOND RESPONDENT

JUDGE:

WILCOX J

DATE OF ORDER:

27 MAY 2005

WHERE MADE:

SYDNEY

THE COURT DIRECTS THAT:
1.The matter be stood over for preparation by counsel of short minutes of proposed orders.

Note: Settlement and entry of orders is dealt with in Order 36 of the Federal Court Rules.

IN THE FEDERAL COURT OF AUSTRALIA

NEW SOUTH WALES DISTRICT REGISTRY

NSD 1078 of 2004

BETWEEN:

AUSTRALIAN PORK LIMITED
FIRST APPLICANT

WINDRIDGE FARMS PTY LIMITED
SECOND APPLICANT

AND:

DIRECTOR OF ANIMAL AND PLANT QUARANTINE
FIRST RESPONDENT

FAYMAN INTERNATIONAL PTY LIMITED
SECOND RESPONDENT

JUDGE:

WILCOX J

DATE:

27 MAY 2005

PLACE:

SYDNEY

REASONS FOR JUDGMENT
WILCOX J:

This proceeding concerns two decisions made in relation to the importation of uncooked pig meat into Australia. At issue is the manner in which the decision-makers dealt with the need to protect Australian pig farmers from the risk of contamination of their herds by a disease known as post-weaning multisystemic wasting syndrome (‘PMWS’).
The proceeding
The first applicant is Australian Pork Limited (‘APL’), a company formed by Australian pig farmers to represent their interests, including in their relations with governments. The second applicant, Windridge Farms Pty Ltd, owns and operates a number of pig farms near Young, New South Wales.
The first respondent is the Director of Animal and Plant Quarantine (‘the Director’). On or about 10 May 2004, the then Director, Michael Taylor, decided that future importation of pig meat into Australia ‘will be subject to the Quarantine Act 1908 [(Cth) (‘the Act’)] and the application of measures as specified in the section on Quarantine Requirements in the Final Import Risk Analysis (IRA) Report for Pig Meat (February 2004)’. I will call the report ‘the IRAR’. Mr Taylor stated:
‘This policy is to be taken into account by decision makers in accordance with the [Act] and Quarantine Proclamation 1998 [(Cth) ‘the Proclamation’] as amended’.
Mr Taylor’s decision (‘the IRA Decision’) is the first decision under challenge in this proceeding.
No issue is taken with that aspect of the IRA Decision which concerns the applicability of the Act and Proclamation to the importation of pig meat. It is the application of the control measures recommended in the IRAR to permit decisions with which the applicants take issue.
On or about 30 July 2004, a delegate of the Director granted to Fayman International Pty Ltd (‘Fayman’) a permit to import uncooked pig meat into Australia from the United States of America between 30 July 2004 and 30 July 2006. The permit was granted subject to conditions that reflected Mr Taylor’s decision to adopt the control measures recommended in the IRAR. It is common ground that, in deciding to grant the permit, the delegate applied the IRA Decision. The delegate’s decision (‘the Permit Decision’) is the second decision challenged in this proceeding.
Fayman is the second respondent to this proceeding. However, the company filed a submitting appearance and took no part in the hearing of the proceeding. Having regard to that fact, it is convenient to refer to the first respondent, in these reasons, simply as ‘the respondent’.
The applicants’ challenge to the validity of the Permit Decision does not depend upon any matter lying outside the acceptability and adequacy of the IRAR and/or the validity of the IRA Decision.
In their amended application, the applicants rely on two bases of the Court’s jurisdiction: the Administrative Decisions (Judicial Review) Act 1977 (Cth) (‘the ADJR Act’) and s 39B of the Judiciary Act 1903 (Cth). The validity of both decisions is challenged on four grounds:
(i)error of law;
(ii)failure to take into account a relevant consideration;
(iii)unreasonableness; and
(iv)no evidence.
All the grounds are based upon alleged deficiencies in the IRAR.
No issue has been raised concerning the applicants’ standing to maintain the proceeding.
PMWS
Professor Roger Morris, who gave expert evidence on behalf of the applicants, described PMWS. Professor Morris is Professor of Animal Health at Massey University in New Zealand. He is also Director of the Massey University EpiCentre, a unit which provides research and consultancy services worldwide in animal health and disease control and offers postgraduate training in epidemiology and related fields such as animal health economics and pig health.
Professor Morris obtained degrees of Bachelor of Veterinary Science with Honours from the University of Sydney and Master of Veterinary Science from the University of Melbourne. He spent 11 years at Melbourne University teaching clinical medicine, preventive medicine and epidemiology. During this time, he also undertook clinical veterinary work with cattle, sheep, pigs and horses.
In 1977, Professor Morris obtained a Doctor of Philosophy degree from the University of Reading, England, for work on the analysis and computer modelling of disease control strategies and integration of economic evaluation into analytical procedures for disease problems.
From 1976 to 1981, Professor Morris was Assistant Director of the Australian Bureau of Animal Health in what is now the Commonwealth Department of Agriculture, Fisheries and Forestry. At various times, he acted as Chief Veterinary Officer of Australia.
Professor Morris then spent five years teaching in the United States of America before taking up his present position in 1986.
Professor Morris has received numerous awards including Fellowships of epidemiological colleges in several countries. He is well qualified to describe the disease that lies at the heart of this proceeding.
In his report, Professor Morris offered this description of PMWS:
‘Post-weaning multisystemic wasting syndrome or PMWS is an important emerging disease of pigs. The name was coined in 1996 to describe a wasting syndrome of weaner pigs first identified in 1991 in high health status Canadian herds. Since then the disease has been recognized progressively in the USA, the UK, most of continental Europe, Asia and most recently New Zealand. In affected areas, the number of herds diagnosed with the disease has also increased during this time. Australia stands out among significant pig-raising countries in that it remains free when virtually all others have become infected over less than a decade.
As its name suggests, PMWS mainly occurs in weaner pigs (6-12 weeks of age) and is a disease that affects several organ systems. Affected pigs are unthrifty, dyspnoeic (have difficulty breathing), and have enlarged lymph nodes, although this last feature is variable. Less frequently, they have diarrhoea, gastric ulcers and icterus (jaundice). At autopsy the lesions in pigs with PMWS are quite variable, although abnormalities in the lungs and enlargement of some or all of the inguinal, mesenteric, bronchial and mediastinal lymph nodes are consistent findings. Lung lesions vary from failure to collapse and increased firmness to extensive to diffuse red to pale tan mottling with areas of consolidation in anterior ventral areas. Non-collapsing lungs at autopsy represent one of the strong indicators of the disease. Histologically there is multifocal lymphohistiocytic to disseminated granulomatous interstitial pneumonia, often with giant cells. In affected lymph nodes, depletion of lymphocytes together with histiocytic inflammatory infiltration is consistently described.
The most characteristic feature of PMWS, although not always present, is the occurrence of intensely basophilic inclusion bodies in many of the affected tissues that are rich in porcine circovirus (PCV) antigen and from which PCV can invariably be isolated.’
There are two forms of PCV. The form that received attention in this case is known as PCV2. Professor Morris said this form of the virus ‘is ubiquitous in pig herds in all parts of the world examined, and it is rare to find a herd free of the virus’.
Professor Morris said PMWS:
‘behaves as a propagating epidemic both between herds and within herds. It has moved from country to country in the last decade, in some cases with an identifiable method of entry. At first when it reaches a country only a few herds are affected, but then it starts to spread more rapidly and becomes very difficult to control, especially in pig-dense areas where there are various forms of interchange between herds. High biosecurity is protective for herds, but does not eliminate the possibility of infection. Movement of recently weaned pigs on to a farm is the single most important method of transfer of infection, but feed or equipment contaminated with the agent can probably also spread it to some degree. There are indications that the agent may be capable of windborne transmission between farms over short distances.’
After detailing experience with PMWS in Great Britain and Denmark, Professor Morris said:
‘Within herds, in some cases the event starts with a period of reproductive problems in sows, but after several weeks disease starts to appear in weaner pigs in the form of wasting and breathing difficulty in a number of pigs, leading to death in about 10 to 14 days. As some pigs die, other previously healthy pigs become affected and also die. Deaths stop when surviving pigs pass out of the susceptible age range. A very characteristic feature of the disease is that antibiotics and other forms of medication have no worthwhile impact on the course of the disease, indicating that the cause is likely to be a virus.
Thus all of the evidence points to this disease being caused by a novel virus, but all efforts so far to isolate a new virus have been unsuccessful.’
Turning to the impact of PMWS on herds, Professor Morris said:
‘Morbidity and mortality are most severe in newly affected herds where 4 to 20% of pigs are usually affected (range 1-60%); of which 70-80% usually die (range 30-100%). After a period which may last from several months to a few years, the disease situation settles down and losses are lower. However herd mortality and growth performance rarely return to pre-disease levels. Herds which trade extensively in pigs may be affected continuously because there are always susceptible pigs entering the farm. The disease is sufficiently severe to force a significant number of affected producers out of business, and the costs of control are substantial in herds which decide to live with the disease.
In New Zealand, affected herds have now been carefully assessed for mortality rate in pigs between 4 and 12 weeks of age. Typical mortality rates in unaffected herds are 0.5 to 3%, with some herds kept under adverse environmental conditions higher. Mortality rates in affected herds varied between 10 and 70%, with one very well managed herd a little lower.’
Although Professor Morris is of the opinion that a new virus is the likely co-factor with PCV2, in causing PMWS, he accepts the possibility that the causal agent may be a new, particularly virulent, strain of PCV2. In his report, he used the term ‘Agent X’ to cover both these possibilities. He was not prepared to rule out the further possibility that Agent X operates in conjunction with other agents. He did, however, disagree with the opinion of some other researchers that the critical co-factor of PMWS was genetic or arose out of handling or environmental factors. He said those possibilities are excluded by the findings of a study in New Zealand. Apparently, PMWS has been encountered in a number of North Island piggeries, but nowhere on the South Island. Yet, according to Professor Morris, a detailed comparison between the two sets of piggeries revealed no significant difference between the genetic characteristics of the pigs, their handling or environmental factors.
I need not form any view about the likely cause of PMWS. The cause is a matter of vigorous debate between well-qualified scientists, without there being any conclusive proof of the correctness of any particular view.
The legislation
The Quarantine Amendment Act 1999 (Cth) introduced into the Act what counsel for the respondent (Mr J Basten QC, Mr S J Gageler SC and Mr G R Kennett) described as ‘three key concepts’. They described these concepts in this way:
‘(1)that quarantine is concerned not only with what occurs at the border but extends to encompass the “introduction, establishment or spread” of a disease: s 4(1)(b);
(2)that quarantine measures may extend beyond simple prevention to “control”: s 4(1)(b);
(3)that there will be a “level of quarantine risk” which is a function not only of the probability of a disease being introduced, established or spread but also of the probable extent of any harm: [s]5D.’
Counsel referred to the following statement in the explanatory memorandum for the Bill which became the 1999 amending Act:
‘Australia’s quarantine policy is based on the concept of the management of risk to an acceptably low level. The natural and economic movement of people, animals, plants and goods results in an inevitable quarantine risk to Australia. Australia’s approach is to manage risk in a manner that provides appropriate protection for Australia, is based on scientific reasoning and is consistent with international rules and standards.’
Section 4(1) of the Act is as follows:
‘In this Act, quarantine includes, but is not limited to, measures:
(a)for, or in relation to:
(i) the examination, exclusion, detention, observation, segregation, isolation, protection, treatment and regulation of vessels, installations, human beings, animals, plants or other goods or things; or
(ii) the seizure and destruction of animals, plants, or other goods or things; or
(iii) the destruction of premises comprising buildings or other structures when treatment of these premises is not practicable; and
(b)having as their object the prevention or control of the introduction, establishment or spread of diseases or pests that will or could cause significant damage to human beings, animals, plants, other aspects of the environment or economic activities.’ (Original highlighting)
Section 5 of the Act defines the term ‘Quarantinable disease’ as ‘any disease declared by the Governor-General, by proclamation, to be a quarantinable disease’. PMWS has been proclaimed a quarantinable disease.
Section 13 of the Act empowers the Governor-General to do various things by proclamation. Pursuant to that power, the Governor-General made the Proclamation. It contains two relevant provisions.
Clause 39 of the Proclamation prohibits the importation into Australia of meat or meat product unless the Director has granted an importation permit.
Clause 70 of the Proclamation stipulates the matters that the Director must take into account in deciding whether to grant an importation permit. It relevantly says, the Director:
‘(a) must consider the level of quarantine risk if the permit were granted;
and
(b)must consider whether, if the permit were granted, the imposition of conditions on it would be necessary to limit the level of quarantine risk to one that is acceptably low; and
…
(c)may take into account anything else that he or she knows that is relevant.’
Clause 70 contains a note that the term ‘level of quarantine risk’ is defined in s 5D of the Act.
Section 5D of the Act says:
‘A reference in this Act to a level of quarantine risk is a reference to:
(a)the probability of:
(i)      a disease or pest being introduced, established or spread in Australia, the Cocos Islands or Christmas Island; and
(ii)     the disease or pest causing harm to human beings, animals, plants, other aspects of the environment, or economic activities; and
(b) the probable extent of the harm.’
The import risk analysis report
(i)        Introductory
As the IRAR is at the heart of this case, it is desirable immediately to refer to the parts of it that are relevant to this case.
The IRAR itself comprises two volumes totalling 767 pages. A third volume contains annexes. The IRAR was the product of a lengthy inquiry undertaken by a five-member risk analysis panel (‘the Panel’) comprising: Dr David Banks, General Manager of Animal Biosecurity in Biosecurity Australia; Dr Robyn Martin, Manager of Animal Biosecurity in Biosecurity Australia; Dr Kevin Doyle, Veterinary Director of the Australian Veterinary Association; Dr Ross Cutler, Consultant Specialist Veterinarian; and Professor Colin Wilks, Consultant Microbiologist. Two technical working groups, one of which was concerned with PMWS, assisted the Panel.
The IRAR explained that, under existing policy, uncanned, uncooked pig meat could be imported only from the South Island of New Zealand, Canada and Denmark. The approximate proportion of imports from each of these sources was respectively 5%, 60% and 35%. Canadian and Danish pig meat had to be imported deboned and cooked on arrival in Australia. These requirements were imposed in order to address the quarantine risk associated with the potential presence of porcine reproductive and respiratory syndrome (‘PRRS’). Pig meat could be imported from any country if the meat was imported in a sealed container, the contents of which had been heated to at least 100°C.
Although the evidence and arguments are confined to the risk to Australian pigs from PMWS, it is important to note that the IRAR also discusses the risk posed by 11 other diseases.
In an introductory section of the IRAR, the Panel referred to s 70 of the Proclamation and commented:
‘As can be seen from the above extracts, the legislation establishes the concept of the level of biosecurity (quarantine) risk as the basis of decision-making under Australian quarantine legislation.
Import risk analyses are a significant contribution to the information available to the Director of Animal and Plant Quarantine – a decision maker for the purposes of the Quarantine Proclamation. Import risk analysis is conducted within an administrative process – known as the IRA process (described in the IRA Handbook).
The purpose of the IRA process is to deliver a policy recommendation to the Director of Animal and Plant Quarantine that is characterised by sound science and by transparency, fairness and consistency. The key elements of the IRA process are covered in “Import Risk Analysis” below.’
The IRAR proceeded to refer to Australia’s international rights and obligations, stemming primarily from the World Trade Organization’s Agreement on the Application of Sanitary and Phytosanitary Measures (‘the SPS Agreement’). The Panel explained:
‘The SPS Agreement recognises the right of WTO Member countries to determine the level of sanitary and phytosanitary protection they deem appropriate, and to take the necessary measures to achieve that protection. Sanitary (human and animal health) and phytosanitary (plant health) measures typically apply to trade in or movement of animal and plant based goods within or between countries. The SPS Agreement applies to measures that may directly or indirectly affect international trade and that protect human, animal or plant life or health from pests and diseases or a Member’s territory from a pest.’

The Panel noted that the SPS Agreement allows WTO members to determine the appropriate level of sanitary and phytosanitary protection (‘ALOP’) but this determination is required to be based on scientific principles and not maintained without sufficient scientific evidence. The Panel went on to say that Australia expresses its ALOP in qualitative terms. The ALOP is ‘aimed at reducing risk to a very low level, but not to zero’.
As I have mentioned, there is uncertainty as to the identity of the co-factor or co-factors which, with PCV2, cause the onset of PMWS. Some scientists question whether there is an infectious co-factor. However, the Panel proceeded on the conservative basis that this is at least a possibility, as all the relevant experts who gave evidence in this case agreed. Accordingly, the IRAR frequently referred to an ‘infected’ carcass or ‘infected pigs’, although the more neutral term ‘affected’ might better describe the present state of expert knowledge.
(ii) The risk estimation matrix
The IRAR set out, as Table 10 on p 14, a ‘Risk estimation matrix’. It took the following form:
At p 24, in a section of the IRAR explaining their adopted method of assessing import risk, the Panel said the assessment should take into account both ‘the likelihood that a pathogenic agent will enter an importing country’ (‘release assessment’) and ‘the likelihood that susceptible animals will be exposed to that agent’ (‘exposure assessment’). In the context of PMWS, ‘susceptible animals’ means healthy pigs. PMWS has not been found in humans or in other animal species. The likelihood of establishment and spread, and the biological and economic consequences of introducing a pathogenic agent were to be determined through a ‘consequence assessment’. The Panel said:
‘The risk assessment for each identified agent concluded with “risk estimation”, the combination of the likelihoods and consequences, and yielded the unrestricted risk estimate.’
The ‘unrestricted risk’ is the risk that exists before the application of conditions designed to reduce the risk level. The risk after application of recommended conditions is termed ‘restricted risk’.
At p 27 of the IRAR, the Panel said: ‘Quantitative data were not available to support many of the probabilities assigned to the pathway steps considered in this analysis’. ‘Likelihoods’ were therefore derived from ‘expert judgements’. If the likelihood was described as ‘high’, this meant ‘the event would be very likely to occur’. If it was ‘moderate’, this meant ‘the event would occur with an even probability’. If it was ‘low’, ‘the event would be unlikely to occur’. If it was ‘very low’, ‘the event would be very unlikely to occur’; and so on to ‘extremely low and negligible’.
The Panel said:
‘In order to ensure consistency in the usage and interpretation of these six terms and definitions, and to provide a framework under which they could be logically and transparently combined, the 0-1 interval for likelihood was divided into six categories. Events considered almost certain to occur were assigned a likelihood of 1.
High  >0.7       ®     1
           Moderate  >0.3       ®     0.7
           Low  >0.05    ®     0.3
           Very low  >0.001    ®     0.05
           Extremely low            >10^-6      ®     0.001
           Negligible                   >0        ®     10^-6’
This means that a likelihood is to be regarded as ‘high’ if there is a 70-100% probability of its occurrence, ‘moderate’ if the probability is 30-70% and ‘low’ if 5% to 30%. Counsel for the applicants criticised the wide range of probability included in ‘moderate’.
The IRAR stated that ‘[t]he band of cells in Table 10 [reproduced at para 39] marked “very low risk” represents Australia’s ALOP, or tolerance of loss’. These cells occur in the following situations:
(i)‘very low’ consequences, even with high or moderate likelihood of entry and exposure;
(ii)‘low’ consequences with low likelihood of entry and exposure;
(iii)‘moderate’ consequences with very low likelihood of entry and exposure;
(iv)‘high’ consequences with extremely low likelihood of entry and exposure;
(v)‘extreme impact’ consequences with negligible likelihood of entry and exposure.
(iii) Assessment of consequences
The consequences line has an important bearing on the risk matrix results. So it is desirable to note the Panel’s explanation of assessment of consequences. At p 63, the IRAR stated that direct and indirect consequences were estimated at four levels: (local, district/regional, State/Territory and national). The IRAR said the first step was to assess the magnitude of the impact of the particular disease on the national economy or Australian community; if there was no discernible impact at that level, in descending order the magnitude of impact at other levels would be investigated.
In assessing consequences, the Panel addressed exposure to PMWS of three different groups of Australian pigs: feral pigs, backyard pigs and pigs in small commercial piggeries. It seems the Panel had in mind the possibility that pigs in the latter two groups might be fed discarded pig meat scraps and that feral pigs might obtain them by scavenging at rubbish tips.
The Panel’s discussion of consequences, in relation to PMWS, commences at p 385 of the IRAR. The technical information set out in the IRAR includes a comment that ‘[i]ncreasing evidence continues to support the hypothesis that PCV2 is essential for the development of PMWS’. Consequently, the Panel paid some attention to transmission of this disease. At p 389, the Panel said it was unaware of any studies that have examined skeletal muscle for the presence of PCV2 viral antigen or virus’. The Panel also said ‘[i]t is unknown if pigs can be infected orally with PCV2’. However, it said: ‘The detection of the virus in oronasal secretions and faeces is compatible with an oral route of transmission’.
Pages 390-391 contain a ‘release assessment’ in which the Panel referred to a series of potentialities and ascribed a likelihood to each. They were as follows:
R1-   ‘the likelihood that a source herd is infected’ – assessed as ‘moderate’;
R2-   ‘the likelihood that a slaughter-age pig from an infected herd is infected’ – assessed as ‘moderate’;
R3-   the likelihood of non-detection. The Panel thought the sensitivity of ante-mortem, slaughter and processing procedures in detecting and removing subclinically infected pigs was ‘extremely low’. In other words, there was an extremely high likelihood that any subclinical PMWS infection in imported carcasses would escape detection;
R4-   ‘the likelihood that the pathogenic agent will be present in the meat harvested for export’ – assessed as ‘moderate’;
R5-   ‘the likelihood that the pathogenic agent will not be destroyed by the post-mortem decrease in muscle pH that accompanies carcass maturation – assessed as ‘high’;
R6-   ‘the likelihood that the pathogenic agent will not be destroyed during cold storage and transport’ – assessed as ‘high’.
The Panel offered this conclusion:
‘When these likelihoods were inserted into the simulation model, it was concluded that, in the absence of risk management and without considerations regarding the exporting country, there was a “low” likelihood that imported pig meat derived from an individual carcass would be infected.’
(iv) Estimate of annual exposure
The Panel went on to consider annual exposure assessments (‘the L factor’) for each of the three groups of pigs. It is unnecessary to set out the components of each assessment. The Panel’s conclusion in respect of each group of pigs was that the overall annual likelihood of entry and exposure for that group was ‘high’.
(v) Estimate of outbreak scenario likelihoods
The Panel then estimated the likelihood of each outbreak scenario. It assessed there was a moderate likelihood of transmission of the disease from an exposed herd of feral pigs to a more general population of feral pigs and to backyard pigs but only a low likelihood of transmission to a more general population of domestic pigs, including pigs in medium-large piggeries. However, with infected backyard pigs there was a high likelihood of transmission to pigs in a more general population of pigs. Similarly, if the infection was in small commercial piggeries.
(vi) Estimate of impact of PMWS in various groups
In assessing the impact of an outbreak of PMWS in each of the three postulated groups, the Panel used letters (A to G) to indicate a rating. The earlier the alphabetical position of the letter, the less significance was to be ascribed to that effect. The significance to be ascribed to each of the letters depended on whether the assumed effect had consequences on a national, State/Territory, district/region or only local level. That appears from Table 8 of the IRAR which is reproduced below:
The Panel concluded (at p 399) that an outbreak of PMWS that was confined to a directly exposed group of pigs would have only a B rating on animal health and an A rating on eradication programs and trade and industry (because the presence of the disease would be unlikely to be detected). However, if the disease spread to a local population of pigs in backyard or small commercial piggeries, the effect on animal health and domestic trade would be C, although the effect on international trade only B.
The scenario assessment relating to a possible secondary spread, via feral pigs or other means, to a more general population of domestic pigs, including medium-large commercial piggeries, is both more important and more controversial. At p 402, the Panel explained:
‘Under this scenario, PMWS would have established in a broader population of commercial piggeries (including medium-large piggeries) and be identified. If the disease was not widespread in the Australian pig population, a control program may be implemented, alternatively, if widespread, control would likely be left to individual producers.’
The Panel noted high mortality rates in the United Kingdom, although they were apparently lower in Canada, the United States and Germany. The Panel said:
‘On balance, the direct impact on animal health was considered unlikely to be discernible at the national level, but would be of minor importance at the State level. This gave the disease a rating of “D” for this criterion.’
The effect on domestic trade was similarly assessed. No figures were mentioned. Nor did the Panel make any distinction between the possible effect of PMWS in one State or Territory, as compared with any other State or Territory; for example, because of differences in their pig populations. Table 8 allowed State/Territory effects (however serious) to be categorised only as ‘minor’ (impact score D) or ‘unlikely to be discernible’ (impact score C). Unlike the situation in relation to national effects, there was no option of classifying a State/Territory effect as ‘highly significant’ (impact score G) or ‘significant’ (impact score F).
In considering the indirect effect of a secondary spread of PMWS to a general population of domestic pigs, the Panel assigned a C to the impact on eradication, control and compensation strategies and a D to the effect on domestic trade or industry.
The Panel said that, when the direct and indirect impacts of PMWS in each scenario were combined, using the decision rules that it had adopted, the consequences ranged from ‘negligible’ to ‘low’. Combining these consequences with the assessed likelihoods, the overall likely consequences associated with the exposure of feral pigs to infected pig meat scraps were considered very low, and those for backyard pigs and pigs in small commercial piggeries were considered to be low.
It is to be noted that this assessment was made on an annual basis; that is, there will be a ‘low’ risk to backyard pigs and pigs in small commercial piggeries in each year, not a low risk of infection overall. The Panel did not make any assessment of the degree of risk of infection over a longer period of time.
(vii) Recommendations for reduction of risk
A ‘low’ risk exceeds the ‘very low risk’ that is Australia’s ALOP. Consequently, in the concluding chapter of the IRAR, the Panel discussed the options for further reducing the risk. At page 745 it said:
‘The likelihood that PMWS could enter, become established and/or spread in Australia via imported pig meat could, in theory be reduced by the application of some or all of the following measures:
·a requirement that the pigs of origin had never been in a PMWS infected country or zone since birth;
·a requirement that slaughter and processing ensured removal of organs and tissues which are sites of predilection for the virus;
·reduction in the volume of pig meat waste discarded in Australia.
As porcine circovirus has been reported to be stable at a temperature 70ºC for 15 minutes, the Panel did not examine the direct effect of processing (other than canning) on the destruction of this virus. Options were examined to identify the least trade restrictive measures which would reduce risks within Australia’s ALOP.’
In relation to canning, the Panel commented at page 745:
‘Australia currently accepts shelf stable canned pig meat from any source country subject to certain conditions. The Australian import conditions for canned meat include a requirement that all portions of the contents have been heated to at least 100ºC. Porcine circovirus has been reported to be stable at 70ºC for 15 minutes. The Panel considered that PCV2 would be inactivated in canned pig meat heated to at least 100ºC.’
The Panel then turned to the possibility of modified dressing of the carcass. I will set out its discussion of this matter, omitting publication references. Counsel for the applicants (Mr J T Gleeson SC and Mr M J Leeming) complained that the passage dealt only with PCV2 (this apparently being ‘the virus’ referred to) and assumed, without knowing, that what is true of PCV2 is also true of PMWS. The passage read:
‘Modified dressing of the carcass to remove certain tissues where the virus has an affinity would influence the fourth step in the release pathway (R4). This step describes the likelihood that the pathogenic agent would be present in meat harvested for export. Modified dressing of the carcass may also influence the exposure step L2, which describes the likelihood that a waste unit would contain a sufficient dose of PCV2 to initiate infection.
Lymphoid tissues are the primary target tissues of PCV2, as for many other viruses. Viral antigen or nucleic acid is found in lymphoid tissues, including peripheral lymph nodes of clinically healthy and diseased pigs. Viral nucleic acid has been detected in bone marrow … and in serum for up to 16 weeks ... Viral nucleic acid has also been detected in sera of slaughter-age pigs … It is possible that these pigs may have been recently infected.
The Panel examined removal of major peripheral lymph nodes (i.e. removing the head and neck and removal of other major peripheral lymph nodes such as inguinal, popliteal, axillary etc) together with deboning the carcass on the above likelihoods. The Panel considered that removal of the head and neck, including any remaining tonsillar tissue, and lymph nodes draining the pharynx, other major peripheral lymph nodes and deboning could reduce the likelihood assigned to R4 from “moderate” to “low”.
Moreover, if meat is sourced from areas other than the head and neck and other major peripheral lymph nodes are removed together with bone, the amount of virus present in a waste unit would be reduced. It is known that the virus has a strong affinity for lymph nodes … Virus titres of approximately 10⁵ to 10⁶ TCID₅₀/g of lymph node have been reported from clinically healthy pigs experimentally infected with PCV2 … Levels of virus in both serum and lymph nodes decrease with increasing time post-infection. In persistently infected pigs levels of virus in tissues are likely to be low.
Given the likely level of virus in muscle per se, the composition of pig meat waste (bone-out) and the volume of waste consumed by a pig, it was considered that the likelihood assigned to L2 could be reduced from “moderate” to “very low”.’
Turning to reduction in the volume of discarded waste, the Panel opined:
‘that if meat was deboned and processed either by cooking or curing, the proportion of pig meat purchased by households and food service establishments that was discarded as waste would be reduced to one tenth of that estimated for the unrestricted risk.’
The Panel went on to express the opinion that a combination of removal of peripheral major lymph nodes, deboning and cooking or curing, would reduce the previously ‘low’ risk to ‘very low’ and thereby meet Australia’s ALOP.
The Panel attached to the IRAR a draft biosecurity policy document setting out proposed quarantine requirements in respect of the importation of pig meat. They included (cl 3.2) a requirement that the Official Veterinarian certify, amongst other things, that:
‘The pigs from which the meat was derived have been kept since birth in a country or zone which is recognised by Australian authorities as free from post-weaning multisystemic wasting syndrome (PMWS). or
The pig meat has been processed by canning such that all portions of the contents have been heated to at least 100ºC. or
The meat has not been derived from the head or neck, major peripheral lymph nodes have been removed, meat has been deboned and the product is processed (cooked or cured). or
The pigs from which the meat was derived are not from a country or zone recognised by Australia as free from PMWS and the meat has not been processed by cooking or curing as above.
Note: In this case, the meat must be processed in Australia.’ (Original emphasis; detailed instruction notes omitted.)
The applicants make no complaint about permissions for importations that satisfy the first or second of these four alternatives. They challenge the sufficiency of the third and fourth options.
Other evidence
(i)Introductory
It is not necessary to summarise all the other evidence put before the Court. A number of affidavits were read and much documentary evidence was tendered. Most of this evidence was uncontentious, except occasionally as to its relevance. The major factual issue raised by the affidavits concerns the cause of PMWS, a matter about which it is unnecessary for me to reach a conclusion.
However, there is also expert evidence relating to the methodology used in the IRAR, whose alleged deficiencies lie at the heart of the case. It is desirable for me to summarise the views of the experts who dealt with that subject. I will also refer to some documentary evidence tendered by the respondent concerning the circumstances surrounding the Permit Decision.
(ii) The IRAR methodology
(a) Professor A N Pettitt
Professor A N Pettitt is Head of the School of Mathematical Sciences at the Queensland University of Technology. He has published widely, especially in relation to theoretical and applied statistics. For some years, he was a co-editor of Biometrics, a refereed international journal publishing statistical theory related to biological sciences. Professor Pettitt provided a report to the applicants and made an affidavit that was filed on their behalf.
In section 2 of his report, Professor Pettitt noted that the methodology adopted by the IRAR consisted of six parts:
(1)Evaluating and reporting likelihood;
(2)       Release assessment;
(3)       Exposure assessment;
(4)       Consequence assessment;
(5)       Risk estimation; and
(6)       Method of risk management.
Professor Pettit commented:
‘Parts 1, 2 and 3 rely on a risk modelling approach which can be described as Monte Carlo simulation, as implemented in the software package @Risk, together with input values which are elicited from scientific and industry experts. In this report I examine methodological, modelling and implementation issues which are pertinent to all parts of the process. I find that the uncertainty in estimates of modelling inputs has been inadequately and misleadingly modelled and inappropriate assumptions have been made in the modelling.
Additionally, the IRA Report comes to its conclusions based on annual risk whereas an assessment over a longer time period gives insight into the time until a significant disease event occurs which might better reflect Australia’s [ALOP].’

Professor Pettitt went on to describe, in some detail, the evaluation process undertaken in each of the six parts.
In section 3 of his report, Professor Pettitt offered a critical overview of the IRAR’s methodology.
Professor Pettitt noted that the IRAR ‘describes a complex method of import (or quarantine) risk assessment where the method of risk estimation is inherently quantitative with risk varying directly as certain quantities vary’. He gave four examples of variable quantities:
(a)the volume of uncooked pig meat that might be imported;
(b)the amount of waste generated in a twelve month period;
(c)the proportions of Australia’s population residing in different regions; and
(d)the proportions of imported pig meat likely to be purchased by establishments and households in Australia.
In recognition of these uncertain values, Professor Pettitt observed, the IRAR represented them by probability distributions, ‘spreading uncertainty over a range of values with different weights’. He went on:
‘Additionally risk varies with other quantities used in the IRA Report’s methodology which are generally called likelihoods. A likelihood is an uncertain quantity but specifically refers to the probability of a specific event occurring and is mathematically restricted to values in the range 0 to 1. Examples of likelihoods in the IRA Report include the following:
·the likelihood that a source herd is infected (R₁) and the five other likelihoods (R₁ to R₆) for the steps described in the release scenario for imported pig meat …;
·the three disease specific likelihoods (L1, L2, L3) referring to waste units, and the six likelihoods (L4_S and L5_S) concerning accessibility of and location by feral pigs to waste units …; and
· three likelihoods in each of Table 6 and Table 7 …
Such likelihoods are assessed in the IRA Report … using a qualitative approach using a six value ordered scale (from “high” to “negligible”) which is imprecise and ambiguous and therefore would appear to ignore some of the quantitative evidence in the IRA Report and the assumed expert judgement of the IRA Team.
However, such determined likelihoods are combined through a series of mathematical formulae and steps, … to determine an annual likelihood of entry and exposure. The combination is effected using an assumption which replaces a qualitative likelihood value by a stochastic variable which takes with equal probability any value in a range prescribed by the qualitative value of the likelihood … For example each likelihood assigned a value of “moderate” is assigned with equal probability any value in the range from 0.3 to 0.7.
In practice in the IRA Report this is effected by Monte Carlo simulation using a software package called @Risk.
Generally, a particular likelihood could be quantitatively assessed by experts to give a best estimate and a range of probable values leading to a probability distribution representing this expert judgement, in the same way that the annual volume of uncooked pig meat that might be imported is quantitatively assessed in the IRA Report.
The methodology of import risk assessment adopted in the IRA Report therefore has the following consequences for risk estimation:
·expert judgement of likelihoods is not represented accurately and spurious uncertainty is introduced through @Risk simulations; and
·more generally uncertainty of expert judgement and assessment is not handled in a consistent and accurate manner in the IRA Report.
Thus, the conclusions of the IRA Report as to risk are unsound.’
Professor Pettitt pointed out that consequences are evaluated in the IRAR in a qualitative manner. Any uncertainty in the qualitative assessment is ignored. Professor Pettitt adopted a comment in a publication of the Food and Agriculture Organization of the United Nations about uncertainties in estimating the probability of introduction of a pest and its economic consequences. The comment said: ‘It is important to document the areas of uncertainty in the assessment’. Professor Pettitt went on:
‘Certainly consequences, being the impacts of a disease, can be analysed for their possible economic effects and the IRA Report’s methodology states at page 63 this is a consideration. Such an assessment should be quantitative and in monetary terms …
In addition, the IRA Report states that “the consequences are mutually exclusive” … so that total losses are disaggregated over various direct and indirect effects and cannot be counted twice.
Qualitative impact scores are introduced to assess the consequences of each outbreak scenario for each exposure group, but these are qualitative in nature. These impact scores are then combined over direct and indirect impacts using a set of rules which is not additive, whereas they should be additive if economic losses were being combined to find the total loss …
Likely consequences for each outbreak scenario are then obtained as a combination of the likelihood that the scenario would occur (being the likelihood of establishment and/or spread for the outbreak scenario) and the consequences associated with that outbreak scenario using a matrix of rules described in Table 9 on page 68 of the IRA Report. Both scales and the result of the combination are qualitative which means that the rules appear arbitrary depending on ambiguously defined scales of measurement.
The likely consequences for each of the outbreak scenarios for each exposure group are then combined using a set of rules which are not additive in nature. It would be appropriate to have an additive set of rules for likely consequences measured in monetary terms, but the IRA Report’s rules appear to follow an arbitrary “order of magnitude” set of rules …
Overall likely consequence assessment appears to be based on arbitrary rules which do not follow an additive basis which would be appropriate for assessing economic, social and environmental losses in monetary terms. Such an approach leads to inaccuracies in the assessment of likely consequences and therefore risk assessment in the IRA Report.’ (Original emphasis)
In dealing with risk estimation, Professor Pettitt observed as follows:
‘Partial annual risk of exposure for each exposure group is assessed by a combination of likelihood of entry and exposure and consequences of entry, establishment or spread … Likelihood of entry and exposure is assessed on a qualitative scale as a result of @Risk simulation values being converted from a probability on a quantitative scale, over the range from 0 to 1, to a single value on a qualitative scale of six ordered values (being “high” to “negligible”), ignoring any uncertainty in likelihood estimation if it had been accurately assessed and also possibly losing accuracy of the likelihood estimate.
Consequences of entry, establishment or spread are also assessed on a qualitative scale of six ordered values (being “extreme” to “negligible” impacts) ignoring any quantification of losses. Mathematically, risk is the multiplication of probability (likelihood) and loss (consequence) but Table 10 … of the IRA Report used for this combination does not display characteristics of this mathematical operation. For this to be possible, numerical values have to be assigned to the consequence values but that has not been done in the IRA Report.
Partial annual risks for each of the exposure groups are combined to give the overall annual risk for a disease using a set of rules which again are not additive but largely arbitrary … The rules appear to follow an “order of magnitude” rule.
The IRA Report’s approach to risk estimation therefore loses accuracy by using qualitative scales to measure likelihoods and consequences and arbitrary rules to combine these quantities.
It also fails to consider any uncertainty in the assessment of likelihoods and consequences and therefore gives a false impression of precision in the estimation of overall annual risk.’
Professor Pettitt also criticised the fact that likelihood and consequences are assessed on an annual basis. He thought it is ‘reasonable to consider longer periods of time to properly assess import risk’.
Professor Pettitt concluded section 3 of his report by saying:
‘It would appear that the IRA Report, through consideration of unrestricted and restricted risks that meet Australia’s ALOP, gives conditions under which imports of pig meat can take place with minimal trade restrictions. It does not give a basis for decision making which takes into account:
(a)the appropriate assessment of uncertainty for likelihood estimation and the uncertainty of consequences assessment;
(b)the appropriate assessment of consequences and overall annual risk in monetary terms; or
(c)consequences of any realistic scenarios not considered in the IRA Report.’
The points made by Professor Pettitt were developed in some detail in the remainder of his report. It is not necessary to set out that detail. Professor Pettitt commented, at para 4.1, that ‘the literature on risk analysis describes two methods for risk assessment … the qualitative method and the quantitative method’, although he noted that a more recent method (semi-quantitative risk assessment) has been described by Mr David Vose, who gave evidence in this case for the respondents.
Apparently Professor Pettitt had no objection to an approach that adopted either the qualitative or quantitative method. He did have a problem about a mix of the two. At para 4.1.6 he said:
‘The IRA Report … uses what it describes as a semi-quantitative method to assess likelihoods and proportions and to assess risks and restricted risks. However the approach of the IRA Report would appear to use all three methods, qualitative, semi-quantitative and quantitative, in an ad hoc mixed method which leads to inaccuracies. For example, when the method used in the IRA Report is considered for likelihood assessment, then expert judgement and its uncertainty for unknown quantities is constrained in unnecessary ways and therefore generally misrepresents that judgement. For example, consider the assessment of R1 the likelihood that a source herd is infected for Post-weaning multisystemic wasting syndrome … Evidence presented gives values of 18% to 20%, 5.6%, over 20%, over half. The assessment is given as “moderate” covering the range 30% to 70% whereas the data suggest a range of 5% to over 50%.’
During the course of his oral evidence, Professor Pettitt clarified the meaning he attributed to ‘qualitative’, ‘quantitative’ and ‘semi-quantitative’ in this context. He said:
‘If it is purely quantitative you can assign numbers to every ingredient in the analysis and you base that on the best number you’ve got and then you just do your arithmetic? --- Yes.
Right. Now if it is qualitative it no doubt takes on board whatever factual material you’ve got and then makes assessments as to the significance of that actual material. Those assessments depending on the individual participants’ expertise and degree of intelligence, I suppose, common sense and so on, is that right? --- That’s right, yes.
And when you’ve got semi quantitative, you’ve got some data put in but judgments are being made along the way, is that why you use that phrase? --- Yes because in all of the methods I suppose there is a mix of data, hard data being used, and what we might call expert judgment that has to interpret that data in the context of in here the IRA. In some instances there will be more data. In other instances there will be less data and therefore depend more on expert judgment.’
Professor Pettitt complained of unnecessary uncertainty in the IRAR; for example, the number of Australian households was stated to be within a range of 6.8 – 7.6 million, without regard to available Australian Bureau of Statistics (‘ABS’) information on this subject. He said:
‘The approach used in the IRA Report therefore generally does not represent the expert judgement and its uncertainty in an accurate manner and leads to unreliable calculations of the overall annual risk for the diseases under consideration and, therefore, unreliable conclusions about whether or not Australia’s ALOP is met for a particular disease.
These inadequacies are carried through the Monte Carlo simulations which are conducted using the @Risk software package, and result in an arbitrary output distribution which does not adequately represent the underlying science, nor the uncertainty about model inputs in judgments elicited from experts. Monte Carlo simulation allows complicated mathematical calculations to be carried out by drawing random numbers to approximate the calculations to any desired degree of accuracy. The IRA Report’s estimation of the annual likelihood of entry and exposure is a complicated mathematical calculation and the @Risk output distribution incorporates the uncertainty implied by the IRA’s methodology for the input likelihoods.
The necessary consequence of each of these deficiencies is that the IRA Report does not provide a sound and reliable basis for overall risk assessment for each of the diseases assessed using the methodology described in it.
At para 6.2 of his report, Professor Pettitt referred to the Panel’s choice of the 50^th percentile for determining likelihoods. He said:
‘It is standard statistical practice when eliciting likelihoods from experts to also elicit an indication of the uncertainty to be attached to each numerical value, typically as a probability distribution. [He cited some references for this statement.] This uncertainty should be meaningful, expressing as appropriate natural variability and/or lack of precise knowledge. The uncertainty should be based on the state of scientific and expert knowledge and opinion, rather than arbitrarily assigned according to the category of the estimated likelihood as pages 27 to 28 of the IRA Report indicate that they should be. The IRA Report (at page 27) appears to argue that under “Modelling qualitative expert judgement” that if likelihoods use expert judgement then quantitative probability distributions cannot be used which appears to contradict the cited references.
The consequence for the modelling is that there will be an incorrect variability of results over the @Risk simulations, which will not correctly represent the state of scientific and expert knowledge. Then characterisations made on percentiles, such as the 50^th or 95^th, of this incorrect distribution will be invalid. Additionally, they would be largely arbitrary if they were to be compared with the distribution resulting from the uncertainty being correctly assessed for the expert judgment.
In conclusion, the 50^th percentile of @Risk simulations carried out using the methodology of the IRA Report does not provide a robust estimate of likelihood and is instead invalid and largely arbitrary.’
In a report filed on behalf of the respondent, Mr Vose defended the Panel’s choice of the 50^th percentile. Professor Pettitt responded to that defence in para 2.1 of a supplementary report. He said:
‘Choice of the 95^th percentile rather than the 50^th expresses an appropriate degree of caution or conservatism. If we consider the likelihood of an event and we consider making a decision if this likelihood is less than a given threshold, then use of the 50^th percentile (that is, is the 50^th percentile equal to the threshold) implies that we have 50:50 degree of belief that the likelihood is less than the threshold, which we have set for making that decision, rather than greater, whereas use of the 95^th implies we have a 95:5 or, equivalently, 19:1 degree of belief that the likelihood is less than the threshold rather than not.
That is, in the latter case with the 95^th percentile, we are much surer, in terms of our degree of belief, of being below the threshold and this reflects a more conservative approach to decision making. In the case of the IRA, an example would be the decision to classify a likelihood value, say L1, the likelihood that a waste unit is infected (see IRA pages 48 and 51), as either “low” or “moderate”, say, where the threshold value is 0.3. Use of the 95^th percentile reflects an appropriate conservative approach.’
Mr Basten took up this issue in cross-examination of Professor Pettitt. Professor Pettitt agreed that the choice of percentile reflects the person’s level of confidence in the result. He said choice of the 95^th percentile ‘establishes a very high level of confidence’. He agreed it ‘offers a cautious approach in terms of the interpretation of the output of the risk simulations’.
Professor Pettitt agreed that he favoured use of the 95^th percentile in a situation such as this, and that he had described the Panel’s choice of the 50^th percentile as ‘arbitrary’. He explained:
‘To some extent the choice of any particular percentile is going to be one of judgment and then to some extent if one hasn’t explained that judgment appropriately then it would be arbitrary.’
Mr Basten asked Professor Pettitt about his criticism of the Panel having assessed risk only over a one-year period. Professor Pettitt agreed it was impossible to speculate about future knowledge; one had to work on the basis of ‘today’s knowledge’. He explained:
‘I think what is being attempted here with a longer period of time is just to imagine that if you were looking at a 10 year period of time then those 10 years would be like the first year. Nothing had changed much. So you would have 10 years similar to the first year and trying to assess what would happen over that period of time. Not taking into account any other what might be called developments going on in disease protection. Just trying to see the effect of the one year calculation being put over the longer period of time. There is nothing wrong with the one year period of time. … I am just saying that in terms of making decisions then it is useful to know what would happen, what was likely to happen over, say, a five or 10 year period of time. Extrapolating out the results of a one year period of time, keeping everything else essentially fixed.
In broad terms we know, of course, what the answer is: the longer the period the closer you will get to certainty? --- Yes. Yes that is the nature of the IRA calculation.’
Professor Pettitt was asked about his criticisms of uncertainties in the IRAR. Mr Basten took him through three examples in which Professor Pettitt complained of the unexplained adoption of a figure, or range of figures, when ABS figures would have been available. The evidence went on:
‘These were examples, I think you repeat at least one of them later, but these are examples of cases where there is data available? --- Well, I would have thought that the ABS would have been able to offer an opinion as to the accuracy of those numbers.
I understand that but these are cases where there is numerical data indeed available as compared with the situation where there really is no specific data and one is making as it were a purely evaluative judgment on whatever science-based material you have. What I was going to ask you was that that is the situation where you criticise the use of a simple uniform distribution I think, is that right? --- In the semi-quantitative assessment of likelihoods, yes. I was making in the report in general comments as to how uncertainty is addressed in the IRA report.
The idea of a simple uniform distribution is that you can’t assign particular value to a number A or B which is higher or C which is lower, is that fair? --- Well, that’s within the range, yes. So if you take uniform over 30 per cent 70 per cent then you’re giving the same weight to all values between 30 and 70 per cent and no weight to values between nought and 30 per cent and 70 per cent ---
Above 70? --- and 100 per cent.
That may or may not be the best way to assess matters even where there is no specific accurate information, is that your point? --- That is my point. There is a process called elicitation which is well documented in the literature which is this trying to quantify in probability terms what the person, an expert, knows about an unknown quantity.’

Professor Pettit commented on the fact that the same weight was given to a probability lying anywhere between 30 and 70%, but significantly less weight to 29.9%. His point, as I followed it, was that the adoption of categories of likelihood, rather than the use of percentages, necessarily meant the adoption of arbitrarily chosen demarcation points. The professor made a similar point later, when Mr Basten was asking him about his comment that the proliferation of steps necessarily meant a reduction in the assessed risk; even if the risk was assessed as ‘high’ the step would be factored into the computer calculation by a series of figures whose mid-point was 85%. The more times one multiplies a given figure by 85%, the lower the result. Professor Pettitt said:
‘Well I think the point I am making here is essentially the one that because of the semi-quantitative nature of the likelihood assessment then with each new step in a pathway and unless certain is used for that - certain likelihood value is used for that step then the implication is that the highest likelihood assessment is high, which is 85 per cent is its mid-point. So each new stat will bring the overall likelihood down by that proportion, 85 per cent. That is because the IRA and the experts are forced to use the semi-quantitative. They appear to be forced, they don't do anything else but use the semi quantitative approach.
They do use it; yes? --- Therefore, rate things as high, or moderate. Rather than saying, my best estimate for that particular step might be 99 per cent or 98 per cent. Rather than the implied estimate which comes from high, which is 85 per cent. So they are not allowed to say, 98 per cent. It has to be their best estimate. A 98th per cent for a step then it would be categorised as high and converted to an average or mid-point value at 85 per cent.
But that is assuming, isn't it, that they are relatively certain about one step? --- All I am saying is, their best estimate. I would have thought your experts - the experts in the IRA process would have a best estimate of each of these likelihoods and then there would be some uncertainty about that estimate.
HIS HONOUR:   Can I just check the arithmetic? At 8.1.13 you talk about an average equal to 0.85 or 0.52. You get that by multiplying 0.85 by 0.85 by 0.85 by 0.85 - four times? --- I hope so.
But even if you were certain of something, so that you had recorded, well if not 100 per cent 99.9, you have still got to bring it down to 85? --- Yes.
That is your point? --- That is the point of the criticism. Well, no, the IRA process allows certain so probably a few at 99.5 per cent certainly would push it up to one. But if it was 95 or 97 then it might be converted down to high and the 85 per cent. It is not clear what would happen.
You could have four things, four steps, each of which you had a very high degree of confidence in, although not total certainty. The multiplication process obliges you to say it is only just marginally over half and therefore moderate? --- That is the consequence of using the semi-quantitative method.
MR BASTEN:   But your criticism does depend on a belief that in one of these hypothetic examples rather than saying, 85 per cent the scientist is willing to say, with a sufficient degree of certainty, 98 or whatever it may be? --- Well I am not clear how close to one or 100 per cent in an IRA process one would push it up to one and be certain. The implication might be that if one was 98 or 97 per cent then it would be categorised as high.
As high? --- As high. Yes, it could be. I don’t – it is not clear what goes to one and what goes to high in those circumstances.
But that is part of the evaluative judgment; isn’t it? --- Yes, it would be.’
(b)      Professor Ian Gardner
Professor Ian Gardner is a graduate in veterinary science from the University of Sydney. He is currently Professor of Epidemiology in the School of Veterinary Medicine at the University of California, Davis. He is a member (by examination) of the Australian College of Veterinary Scientists in Pig Medicine. He teaches Swine Herd Health to third-year veterinary students and is clinical veterinarian for the UC Davis Annual Science Swine Unit. Professor Gardner has published, and undertaken consultancies, concerning pig health and risk analysis. Professor Gardner gave evidence on behalf of the respondent.
In his report, Professor Gardner noted a request that he provide his opinion ‘as to whether the release assessment (pages 390-391), the exposure assessment (pages 392-395) and the consequences assessment (pages 395-405) for PMWS in the Final IRA provide an appropriate basis for assessing:
(a)the probability of PMWS being introduced into Australia and causing harm to pigs in Australia, in light of the risk management measures proposed at pages 745-749 of the Final IRA; and
(b)the probable extent of that harm.’
Professor Gardner responded:
‘In my opinion, the release assessment, exposure assessment and consequence assessment for PMWS in the final IRA adequately assess points 5(a) and 5(b), listed above. In many of the scenarios and component steps in the IRA, the Panel has taken a very conservative approach to the estimation of risk and its consequences. I believe that the final IRA is a fair and reasonable attempt to incorporate available information on PMWS and most importantly, I could find no “fatal” or “serious” flaws in the IRA. I define “fatal” and “serious” flaws as flaws that would have resulted in a substantial underestimation of probabilities and consequences of PMWS, or overestimation of the effects of the risk management measures.
The release assessment provides a description of 6 sequential steps that need to be met for imported pig meat, derived from an individual carcass, to be infective. I believe the estimation is conservative because pigs may clear PCV2 infection as they age, i.e. the proportion of infected pigs consigned for slaughter is likely less than the proportion of pigs that ever became infected in the same herd.
Estimation of the likelihood that source herds are infected (R1) was a difficult task for the Panel given the non equivalence of PMWS and PCV2, and the lack of high-quality international data. Inadequate data quality is most likely attributable to among-country differences in PMWS surveillance activity and lack of a standardized case definition for international recording of PMWS occurrence (which is not mandatory). Use of PMWS data alone is likely to underestimate the prevalence in pigs at slaughter, so the Panel’s approach of using data for PCV2 nucleic acid in sera (page 390; release assessment) is a very conservative approach since not all the nucleic acid might be infective.
In my opinion, accounting for the variability in prevalence of PCV2 among herds would have been a nice refinement to the model. On the other hand, the Panel seems to have taken a conservative stance by considering PCV2 prevalence to be moderate in slaughter-aged pigs.
With regard to R3, it is likely that the sensitivity of lesion detection would vary with the severity of disease and clinical signs. The assumption of extremely low sensitivity is reasonable given that most pigs would be sub-clinically infected.
…
The IRA allows for different scenarios involving feral pigs (remote regions, rural regions, and large towns). In my opinion, the “moderate” and “high” likelihood assessed for feral pigs in remote and rural regions, backyard pigs and small commercial piggeries is a conservative estimate.
The consequence assessment was based on the description of the characterisation of discrete outbreak scenarios for the 3 different exposure groups, i.e. feral pigs, backyard pigs and small commercial piggeries. Direct impacts on animal life or health and the environment were considered in addition to a range of indirect impacts on a variety of outcomes including trade. Given my understanding of pig production in Australia, I believe that the assessment covered the most likely exposure groups and direct and impact [sic: indirect] impacts should PMWS be established.
Assessment of the overall impact of PMWS included scenario 4 – secondary spread to a more general population of domestic pigs (including medium-large commercial piggeries). This essentially considers an “endemic state” where PMWS is widespread in the industry. Given the awareness of the commercial pig industry and diagnostic laboratories, the existence of rigorous biosecurity practices, I believe that this scenario is unlikely. The likely consequences of the remaining 3 scenarios were all “negligible” or “very low”. Inclusion of scenario 4 added a “low consequence” which meant that the overall consequences were “low” when all 4 possibilities were considered together. The combination of likelihood and consequences into likely consequences resulted in a “very low” overall estimate. Because I consider scenario 4 to be unlikely, I believe that this overall estimate is a conservative one.
The 2003 Draft Guidelines (pp 48-50) describe use of expert judgements/opinion in risk assessment but does not include how to include expert opinion when experts disagree. A number of strategies exist and choice of different methods might result in different inferences. Ideally, how disparate views of the Panel members or the PMWS Technical Working Group were resolved should be documented. I assume the values considered in the model were a consensus view of the Panel (after having access to the same data) and that Panel members were in close agreement on all variables.
It would have been helpful to include a formal sensitivity analysis for each probability or consequence to determine how robust the final conclusions of the IRA were to changes in such values. However, the Panel seems to have taken a consistently conservative approach to estimation, erring on the high side for both probabilities and consequences.’
In a later part of his report, Professor Gardner commented on the Panel’s treatment of uncertainties. He said:
‘The IRA has captured uncertainty in many of the input parameters by allowing for uniform distributions within probability categories. In a stochastic simulation, all values within the range would have an equally likely probability of being sampled. More informative distributions within these ranges could have been used, however there are clearly no data to make them more informative, e.g. use of beta or betapert distributions within each category. Accordingly, I disagree with Dr Morris’ comment 6.3.6., in which he suggests that “no proper consideration is given to the issue of . uncertainty in the likelihood of PMWS .”
In my opinion, the number of sequential steps in the likelihood should be determined by the biology/ecology of the pathogen under consideration and whether data are available for each of those steps … If one step is added at the end of chain with 5 steps, then the final likelihood for a 6-step process will always be less than the 5-step likelihood, unless that probability for the final step is 1. However, if a step is added in the middle of the process for which the starting and ending probabilities are known, then the final likelihood should remain unchanged. It is possible to include probability values of 1 for these intermediate steps, in which case the overall probability value would not change.
It is common in IRAs to use “average values” for such analyses because tracking individual carcasses through the slaughter process and relating test results on a carcass by carcass basis is difficult and rarely done. I am not aware of any longitudinal data with respect to PCV2 that could have been used in the IRA. If these are available, the reviewer should provide references for the Panel.’
Professor Gardner concluded:
‘My overall conclusion is that the findings of the final IRA are appropriate based on my review of the supportive documentation. In my opinion, the final IRA is a fair and reasonable attempt to incorporate published information about PMWS and its associated risks. The final IRA follows designated Biosecurity Australia guidelines as laid out in 2003 Draft Guidelines and also it appears to meet guidelines in the OIE code and the SPS Agreement under WTO.
In general, I consider that the IRA was based on sound scientific principles using available knowledge, and that it is structured and transparent. In addition, I consider that it provides an outcome that 1) supports the estimation of “risk” and 2) enables risk to be evaluated against Australia’s ALOP, and 3) allows the valid comparison of risk management measures. For each scenario, the IRA includes disaggregation of the likelihood estimate into its individual component likelihoods.
I did not identify flaws that were sufficiently serious or fatal to negate the conclusions and recommendations in the IRA. Annex C documents the extensive consultation with national and international stakeholders and demonstrates that the Panel made a concerted attempt to address concerns that were raised by these outside groups.
As is true for all IRAs, it is important to acknowledge any inherent flaws. These flaws can be broadly categorised as those pertaining to existing knowledge and data (outside of the control of the Panel) and those pertaining to the methodology in the IRA. For PMWS, the lack of a perfect “case definition (and differing opinions about its causes) and incomplete data made it difficult for the risk assessors to select the most appropriate data for risk estimation. The Panel clearly considered the involvement of unknown agents in the PMWS syndrome. The formal incorporation of a sensitivity analysis and documentation of how differences in expert opinion were resolved would have improved the final IRA but I don’t consider that their omission has compromised the overall validity of the IRA.
To set the final IRA in context, one should consider the fact that there have been 14 years of introduction of pig meat from Canada and Denmark (both countries have PMWS) into Australia with less restrictive import quarantine conditions and there have been no PMWS diagnoses in Australia. In future, it is possible that the volume of imported pig meat might increase compared with the last 14 years. However, the application of the risk management measures (specifically, reducing the amount of waste discarded, removal of the head and neck, bone and major lymph nodes prior to the export of pig meat for cooking/curing in Australia) which was not historically practised should only further protect the health of the Australian pig industry.’
During cross-examination by Mr Gleeson, Professor Gardner expressed agreement with a statement of Mr Vose that ‘semiquantitative risk assessment techniques are currently not widely accepted in international risk issues because of difficulty in retaining transparency and because the process is open to abuse’. However, he also agreed with a rider by Mr Vose that ‘semiquantitative risk assessment when properly executed is a transparent approach that supports the efficient management of a portfolio of risk issues without requiring complete quantifications to the risk or excess risk avoidance’. In relation to transparency, Professor Gardner said he had not seen the spreadsheets underlying the IRAR or any explanation of the Panel’s reasoning for their selection of ‘moderate’ in relation to the likelihood that a source herd is infected. Neither had he seen any report of the number of times the Monte Carlo random allocation had been applied to the various R factors. He accepted failure to report that matter constituted a lack of transparency.
Professor Gardner said he had not seen a 95^th percentile report about the risks discussed in the IRAR. He agreed it was part of his regular practice, when doing a risk analysis, to report on both the 50^th percentile and the 95^th percentile.
Professor Gardner was taken to a footnote (footnote 50 at p 98) in a document published in September 2001 by the Commonwealth Department of Agriculture, Fisheries and Forestry, Guidelines for Import Risk Analysis. The statement was:
‘As a rule, it is recommended that the 95^th percentile of an output distribution be reported. This conservative policy is based on a recognition that all models are (at last to some extent) imperfect representations of reality.’
Professor Gardner said:
‘Yes, I would agree with footnote 50 on the proviso that the original distribution of the data is not shifted upwards. As has been done in this particular risk assessment where a very high artificial initial value was put on for the probability. But if I had modelled this differently with a midline value of 20 per cent I would probably have put forward the 95 per cent probability value as well.
So, does this summarise your opinion? If, contrary to what you have just said, each of the individual integers was done in a fair and reasonable manner then you would have expected both the 50 per cent and the 95^th percentile to be reported? --- If I was doing the risk assessment I would have modelled the things integer values and done 50^th, 75^th and probably 95^th percentile.
And that is standard practice; isn’t it? --- That is common practice.
Now when you read this report did a question occur to you along these lines: why can’t I find in this report information at the 95^th percentile; did that occur to you? --- No it didn’t occur to me at the time.’
Professor Gardner accepted that the IRAR contained no explanation of its omission of 95^th percentile reports. He said he had an impression that there was reasoning supporting the non-reporting of the 95^th percentile in a document issued in 2003. He was vague about that; he said he would have to check. No such document was tendered in evidence.
Professor Gardner agreed with Mr Gleeson that steps R3, R5 and R6 in the release assessment can, for practical purposes, be put aside; the critical steps were R1, R2 and R4, all of which were assessed as ‘moderate’. The professor did not agree that these elements could just as readily have been considered as one; he thought it was an ‘aid to thinking’ to consider each step separately.
Mr Gleeson then referred Professor Gardner to the IRAR’s conclusion about release assessment: there was an overall low likelihood that imported pig meat derived from an individual carcass would be infected. The professor agreed the IRAR did not disclose what effect the recommended conditions would have on this likelihood. This flowed through to a similar omission in respect of L1 – the likelihood that a waste unit is infected. The professor’s evidence went on:
‘What I’m putting to you is that you agree that under this report which is the only information you had, you’re not told after the measures what is the total R figure or the L1, do you agree? --- Yes, I think that’s – that would be a correct interpretation and I find it - - -
And I want to suggest to you that that is a fundamental lack of transparency in this report? --- It would have been helpful to have that documentation, that's correct.
Do you agree with me? --- Yes.
Thank you. Now, can you look at L1 on page 392 and this seems to be an assumption by definition that the likelihood that any individual waste unit which might get before a pig in a tip for instance being infected is the same likelihood as the source carcass had of being infected, correct? --- That's correct.
Now, I want to suggest that in this report when you read it, you did not find any reasoning exposed as to why such an assumption should be made? --- The reasoning could have been clearer, I agree.
What I want to suggest is, leaving aside views you might have on the topic and views others may have, when you read the report, you couldn't find exposed reasoning to justify the conclusion here expressed about L1, do you agree? --- No, it's not explicit.
No, and that's a question on which different views might well be taken, correct? --- Correct.
One view which might be taken is that if for example the pig meat is going into Australia cooked and cured it will largely end up in small goods factories, correct? --- Correct.
In small goods factories there will be a significant risk that meat from different carcasses will be combined? --- I couldn't comment explicitly on how they are combined. That is outside my area of expertise.
But certainly if you were trying to rationally assess L1 you would have to take into account through some intelligent process whether in the small goods factories multiple carcasses get combined, because if they did that might give you an increased L1, correct? --- It may give you an increased L1 under the proviso that infected and noninfected material is being aggregated in similar amounts, that is a possibility.
But I think you agreed that in this report when you read it, you couldn't find any reasoning one way or the other on that type of issue? --- No, there is no obvious reason presented.
But that's a topic about which various people hold opinions and there can be intelligent discussion about it, yes? --- Certainly.
Now would you agree with me that the failure to explain the equation in L1 is a lack of transparency? --- It was presented as an assumption in the report. The basis of that assumption certainly wasn't totally clear.’

Mr Basten rightly emphasised the expert qualifications of the members of the Panel and the technical working group. However, that emphasis points up the vice of the adopted methodology. The selected bands reduce the influence of the Panel’s expertise on the IRAR outcome. Poorly selected probability bands may significantly distort the experts’ true views.
None of the expert witnesses sought to justify the Panel’s choice of probability distribution bands. The IRAR did not advance any justification. None of the Panel members gave evidence explaining their band selection. Professor Gardner was critical of the course taken in the IRAR. He told Mr Gleeson that, ‘if there were hard data available and it [the L factor for feral pigs] could be modelled as anything but a uniform distribution between 70 and 100 percent then I would certainly model it with a different shaped distribution if that were more appropriate’: see para 104 above. He also said he would take into account any available information about the actual percentage of an integer in the assessment: see para 105.
Professor Gardner would have tried to obtain numerical data wherever possible. He agreed with Mr Gleeson’s suggestion (para 110 above) that, in assessing the consequences of a secondary spread of PMWS to a more general population of pigs ‘in an ideal world’, he would express a best estimate and a range in numerical terms. See also Professor Gardner’s expression of concern (para 114) about ‘the way it [the model] was done’ and his wish for ‘better numeric values to place on some of these inputs’.
Even Mr Vose, the expert witness who was most supportive of the IRAR, recognised the problem caused by its adoption of broad probability distribution bands: see paras 155 and 156 above. He pointed out that ‘density falls sharply to zero at the minimum and maximum in an unnatural way’; there will always be ‘a value that is on the cusp’. Indeed, he said, ‘perhaps the only really good use of a uniform distribution is when you want to exaggerate your uncertainties and it allows you to do a sensitivity analysis’.
Of course, that was not the purpose of the uniform distribution in the present case. Its effect was to provide a result that the Panel may not otherwise have reached and to suggest a degree of certainty that the Panel may not in fact have possessed.
(d) use of the 50^th percentile
As counsel for the applicants pointed out (para 196 above), the IRAR claimed its analysis had been modelled in accordance with the 2001 Guidelines. In one important respect, at least, it had not. Those Guidelines recommend reporting the 95^th percentile of output distributions. Although some 95^th percentile data was included in the Annexes, the results stated in the IRAR itself, which results were those taken into the Monte Carlo simulation, reflected 50^th percentile values. The IRAR gave no reason for this departure from the Guidelines.
Professor Gardner said that, if he had been doing the analysis, he would have ‘done 50^th, 75^th and probably 95^th percentile’; it is common practice to do this: see para 100 above. See also the evidence of Professor Pettitt mentioned at paras 86 to 88 above.
Perhaps the Panel’s departure from the Guidelines and common practice might be justified if, as Mr Vose speculated, the Panel had knowingly adopted a conservative approach in all other respects. Although at the price of sacrificing transparency, such an approach might yield a result in which the Panel was able to have an acceptable degree of confidence. However, there is no indication in the IRAR, and no evidence to suggest, that the Panel consistently adopted a conservative approach. It certainly did not do so in relation to impact values for R5 and R6, where two assessments of over 99% effectively each became 85%.
(e) the consequences table
Another valid criticism of the IRAR concerns Table 8, dealing with consequences. This table distinguishes between consequences on the national, State/Territory, district/region and local level. The distinction depends on geographical boundaries, not the scale of the envisaged disaster. Subject to two possible qualifications, under a table such as this, a plant disease that had the potential to wipe out all sugar cane growing north of a particular latitude in southern Queensland would be classified only as having ‘State/Territory’ consequences. On the other hand, a disease that wiped out the Australian cotton crop would have a ‘national’ effect; cotton is grown in both New South Wales and Queensland.
The first possible qualification to that comment is a statement at the top of p 64 of the IRAR: ‘At each of the lower levels, an impact more serious than “minor” was deemed to be discernible at the level above’. Counsel differed as to the meaning of this statement. Counsel for the respondent argued that the sugar cane example would be treated as more serious than ‘minor’ and, therefore, as discernible at the national level, even though direct damage was confined to Queensland. Counsel for the applicants contended this interpretation is incorrect; the relevant sentence is governed by the previous sentence that ‘[t]he impact of a disease at a given level in more than one State/Territory, district or local area was considered to represent the same magnitude of impact at the level above’. Even if the respondent’s construction is accepted, the damage would still be classified as ‘minor’, although with an E impact score rather than a D.
The other qualification concerns indirect consequences. Counsel for the respondent argued that a potential disease could be regarded as discernible at the national level if it would significantly affect the value of Australian gross domestic product and/or government revenues and expenditures. Perhaps this is so. However, such an approach involves a difficult question of degree. Whenever production is lost because of disease, there is an adverse effect on gross domestic product and on government revenues/expenditure. At what point does the indirect effect transform a State/Territory effect into a national effect? Why did the degree of PMWS impact implicitly assumed by the Panel fail to meet that threshold? The IRAR does not say. Indeed, there is nothing to suggest the Panel made any estimate of the losses, direct or indirect, likely to be sustained in a PMWS outbreak in Australia. Professor Gardner would have wished to have such data. He said it was ‘usually central to a risk analysis’.
If the Panel are not to be criticised for failing to obtain detailed information about overseas PMWS losses, and then using this information to estimate the likely range of Australian losses, it is because their adopted methodology did not call for hard data. Rather, the methodology encouraged the use of nebulous descriptions like ‘highly significant’, ‘significant’ and ‘minor’, these being assessed by reference to geographical boundaries rather than the industry itself.
(f) conversion of unrestricted risk to restricted risk
The most serious problem about the IRAR, in my opinion, arises out of its conversion of the assessed ‘low’ risk, before application of the recommended conditions, to ‘very low’ risk, after the conditions. This step was critical to the result of the study and the IRA Decision itself. Australia’s ALOP is ‘very low risk’.
I have previously quoted the crucial step in the Panel’s reasoning. It is worth repeating:
‘As PCV2 has been shown to result in persistent infections, has been isolated from many tissues, is a hardy virus and is likely to be transmitted orally, the Panel considered that if an unknown disease agent was involved in PMWS, the risk management measures requiring removal of bone, major peripheral lymph nodes, head and neck and cooking or curing would act to reduce the risks associated with that agent.’
The reasoning in that sentence may be summarised in this way:
(i)PCV2 has certain characteristics, including being present in many tissues and being a hardy virus;
(ii)Therefore, assuming an unknown infectious co-factor of PMWS, particular risk management measures ‘would act to reduce the risks associated with that agent’.
There appears to be no connection between the first proposition and the second. It may readily be accepted, as Dr Allan stated at para 119 above, that the recommended risk management measures would have a tendency to reduce the risk posed by the assumed PMWS co-factor. This acceptance is a matter of common sense; it is not necessary to justify it by reference to PCV2. Any reduction in the volume of imported infected material must have a tendency to reduce the risk of infecting Australian pigs. The problem is that nobody can say whether the reduction would be great or small or sufficient to make a qualitative change in the risk. The Panel did not explain the basis upon, or the reasoning by which, it assessed the risk as having been reduced from ‘low’ (5% to 30%) to ‘very low’, that is, 5% or less. Dr Allan agreed with Mr Gleeson that, even after application of the recommended risk management measures, a carcass might still retain enough of the co-factor to cause PMWS infection: see paras 120 – 122 above.
Like everyone else, the Panel were unaware of the identity of the co-factor or co-factors that, with PCV2, cause PMWS. This was a huge problem, as the respondents’ experts agreed: see, for example, Professor Gardner at para 115 above and Professor Ellis at para 133.
The Panel reacted to the problem by making the conservative assumption that at least one co-factor was an infectious agent, possibly a new virus or a particularly virulent strain of PCV2. That was a reasonable course to take. However, it left the Panel in the position of dealing with an assumed infectious agent of whose characteristics they were unaware.
PCV2 is known to be a particularly hardy virus. So the Panel made a judgment that any co-factor virus was unlikely to be more hardy than PCV2. Counsel for the applicants criticised the Panel for taking that course. Professor Ellis did not think such a judgment could safely be made: see para 132 above. I understand counsel’s criticism; the Panel’s judgment may be wrong. However, I think it was open to an expert body to make this judgment.
On that basis, it seems to me, the Panel was entitled to treat PCV2 as a surrogate for the presumed infectious agent; in the sense that risk management measures that will eliminate the risk of PCV2 infection being imported may reasonably be regarded as ensuring the assumed PMWS infectious agent also will not survive importation.
However, the Panel did not know what measures are necessary to ensure PCV2 infection will not survive importation. Deboning and removal of the head, neck and major lymph glands must help. However, Dr Allan said he did not know the extent to which these steps would reduce or eliminate the volume of PCV2 in the carcass; he had never researched the topic: see para 122 above. Nor was he aware of research by anyone else: see para 123 above. Professor Ellis said, if these steps were taken, he thought the odds would be long on survival of enough infectious agent to cause transmission. But he agreed not much virus was needed for transmission to occur; the virus need not be multiplying in the meat, it is enough ‘if it’s there and it remains alive in a small dose’: see para 131 above.
Accepting the Panel’s entitlement to use PCV2 as a surrogate, in considering what measures were necessary to reduce the risk of infection by the assumed co-factor to ‘very low’, the Panel had no basis for moving beyond what they knew about PCV2. If they did not know whether the recommended measures would be effective to reduce the risk of PCV2 infection to ‘very low’, reference to PCV2 provided no basis for selection of the restrictions necessary to guard against the assumed PMWS infectious agent. Of course, the Panel might have commissioned some research about the effectiveness of the proposed restrictions against PCV2, and used the result of that research in coming to a surrogate conclusion about PMWS. However, the Panel did not take this course.
Another step the Panel might have taken was to commission research, probably overseas, similar to that undertaken in relation to PRRS. Such research might have demonstrated that any infectious co-factor of PMWS (whatever it was) does not survive deboning and removal of the head, neck and major lymph glands. It may have demonstrated that the infectious co-factor would not survive cooking the meat at a particular temperature for a particular period of time. Even though such research may not have revealed the identity of the PMWS co-factor, its results may have enabled the Panel to devise conditions that would be effective against the infectious co-factor, whatever it was.
Mr Basten rightly said that the Panel was not under a legal obligation to commission research. However, the difficulty is that, in the absence of such research, the Panel lacked the information crucial to the final step in their reasoning; with the result that the step lacked rational foundation.
A more particular criticism of the Panel’s reasoning, and conditions, is that nowhere did they explain what they meant by ‘cooking’, an option that was offered as an alternative to curing. The Panel noted that porcine circovirus ‘has been reported to be stable at 70ºC for 15 minutes’. Presumably, this statement was believed to be true of PCV2. Therefore, cooking to 70ºC for 15 minutes would not affect the survival of PCV2. Treating PCV2 as a surrogate for the assumed infectious co-factor of PMWS, nor would it affect the survival of that co-factor. If cooking to 70ºC for 15 minutes was intended to be enough to satisfy the condition, this constitutes a further logical flaw in the Panel’s reasoning. If this was not intended to be enough, the Panel did not say what more was required.
(ii) Consequences of these problems
(a) the applicants’ grounds of invalidity
Counsel for the applicants argued that the problems discussed above mean the IRA Decision is legally invalid. As it is clear, they said, that Dr Carroll took the IRA Decision into account in making the Permit Decision, the invalidity of the IRA Decision also invalidates the Permit Decision.
As I have mentioned, counsel invoked four grounds of legal invalidity. I will refer to them by reference to ss 5 and 6 of the ADJR Act. Section 5 lists grounds referable to a decision to which the ADJR Act applies. Section 6 deals with ‘conduct for the purpose of making a decision to which this Act applies’. The applicants accept that the IRA Decision was not a decision ‘under an enactment’, so as to be caught by s 5 of the ADJR Act; but they argue that s 6 applies. They say the recommendations made in the IRAR constituted conduct for the purpose of enabling the Director and the Director’s delegates to make decisions about the grant of individual permits, each of which decisions was a decision ‘under an enactment’; that is, cl 39 of the Proclamation.
(b) error of law and failure to take into account a relevant consideration
The grounds are error of law (s 5(1)(f) and s 6 (1)(f)), failure to take into account a relevant consideration (s 5(2)(b) and s 6(2)(b)), unreasonableness (s 5(2)(g) and s 6(2)(g)) and no evidence (s 5(1)(h) and s 6(1)(h)).
The applicants’ Points of Claim gave the same two alternative sets of particulars in respect of each of the first two grounds. The first set of particulars (para 1 of the Points of Claim) reads:
‘(a)The respondent was required, pursuant to s70 of the Quarantine Proclamation, to consider the level of quarantine risk if a permit to import pig meat were to be granted by reference to the probability of any disease being introduced, established or spread in Australia and causing harm to animals, and to the probable extent of the harm.
(b)The respondent failed properly to consider the level of quarantine risk that would be incurred in respect of PMWS in the event that a permit to import pig meat were to be granted.
(c)PMWS is a disease which has been described in many countries, but not in Australia.
(d)The virus PCV2 is a necessary but not sufficient factor for the presence of PMWS.
(e)The additional factor necessary for the expression of PMWS is unidentified; it may be an unknown disease agent.
(f)A consideration by the respondent of conditions designed to minimise the quarantine risk of PCV2 (a virus already present in Australia) does not discharge the obligation in s70 of the Quarantine Proclamation in respect of PMWS (or the unknown disease agent which may be involved in its expression).’
The applicants have established items (a), (c), (d) and (e) of these particulars. On one reading, the word ‘properly’ in item (b) invites the Court to review the satisfactoriness of the Panel’s conclusion, a course that is not open. On the other hand, if item (b) is to be seen as a claim that the Panel did not address the question of the level of quarantine risk that would be incurred in respect of PMWS if permits were granted, that claim must fail. That was the whole purpose of the IRAR. Whether it was done well or badly, the question was addressed.
Item (f) is a proposition about the logic employed by the Panel.
The matters (legal and factual) set out in the first set of particulars do not establish either error of law or failure to take into account a relevant consideration.
The second set of particulars is contained in para 3 of the Points of Claim. It reads:
‘(a)The reasoning process leading to the assessment of risk and the formulation of measures to manage that risk focussed on the risk of introduction of a disease in a twelve month period. The assessment of the level of quarantine risk as required by the Quarantine Proclamation was not limited to the risk and probable extent of harm in a twelve month period.
(b)The reasoning process leading to the assessment of risk and to the formulation of measures sufficient to manage that risk applied a computer based calculation of the level of risk.
(c)That reasoning process substituted the rules for the computer based calculation of risk and formulation of measures sufficient to manage that risk for the assessment of the matters set out in clause 70(1)(b) of the Quarantine Proclamation 1998.
(d)The mathematical model purportedly used was incapable of rationally comparing levels of risk with countervailing benefits in a manner which allowed a conclusion that the risk was acceptably low.
(e)The decision failed to consider the level of quarantine risk and its acceptability in respect of each particular permit sought or likely to be sought.’
I do not accept a number of these propositions.
I will start with item (a). Although I have criticised the Panel’s decision to limit their assessment of risk in the IRAR to a 12 month period, I do not think this decision reflects an error of law or a failure to consider a relevant circumstance. Clause 70 of the Proclamation sets out the matters that the Director is bound to consider in deciding whether to grant an importation permit under cl 39. Relevantly, there are only two required matters of consideration: ‘the level of quarantine risk if the permit were granted’ and possible conditions. The Director is commanded to consider the effect of granting the particular permit which is then under consideration. The clause does not require the Director to make, or adopt, a long-term policy intended to guide various decision-makers over an indefinite period of time. The Director is free to take that course: the IRAR was intended to be such a policy. However, it was not, and was never intended to be, itself a statutory decision. No statutory criteria applied to it. Accordingly, whatever the merit of the Panel’s decision to limit their risk assessment to a 12 month period, this does not result in legal invalidity. So far as the Permit Decision is concerned, cl 70 requires consideration only of the merits of the particular application. It says nothing about the cumulative effects of many permit approvals, whether over 12 months or a longer period.

It seems items (b) and (c) of the alternative particulars raise a single point: the use of a computer based assessment of risk. Although I have criticised the methodology adopted by the Panel, in particular the Panel’s selection of bands of probability distribution, I do not think that methodology amounts to an error of law or a failure to take into consideration a relevant circumstance. The Panel knew the issues that would fall for consideration by delegates required to make decisions under cl 39 of the Proclamation. The Panel did not misdirect themselves about those issues. Nor did the Panel fail to address the issues stated in cl 70 of the Proclamation. The Panel provided recommendations as to the manner in which those issues should be determined by individual decision-makers. It is not to the point, in relation to these grounds, that I have concluded there are significant problems about the quality of the recommendations.
In relation to item (d) of the alternative particulars, I do not agree with counsel for the applicants that the Panel was bound to consider the benefits of the importation of pig meat from other countries. Paragraph (c) of cl 70 permits the Director to take into account any other knowledge that is relevant. I see no reason why benefits should not be regarded as relevant. However, para (c) merely confers a discretion on the Director; it does not impose a duty on the Director to consider benefits.
Item (e) of the alternative particulars is misconceived, insofar as it relates to the IRA Decision. The IRAR did not attempt or purport to deal with the risk assessment that needed to be made in respect of each particular permit sought or likely to be sought. It attempted and purported to provide assistance to individual decision-makers about the general level of quarantine risk attendant upon importing pig meat into Australia and as to conditions that might appropriately be imposed. The Panel left it to individual decision-makers to determine how to use that information; the individual decision-makers remained bound to consider the matters set out in cl 70 of the Proclamation. This might require them to obtain and consider additional information, such as information regarding conditions in the relevant exporting country.
Insofar as item (e) of the alternative particulars relates to the Permit Decision, it is not misconceived. However, it is factually incorrect. The issue stated in item (e) was the issue with which Dr Carroll was concerned. Dr Carroll did consider the level of quarantine risk in relation to the application by Fayman. He did so by reference to the IRAR. If there was an error in the IRAR sufficient to lead to a conclusion that the IRA Decision was legally invalid, this will have a flow-on effect to the Permit Decision. But it is not possible to say that Dr Carroll failed to take into account a relevant consideration.
(c) unreasonableness
Paragraph (g) of each of s 5(2) and s 6(2) of the ADJR Act describes this ground in the following way:
‘an exercise of a power that is so unreasonable that no reasonable person could have so exercised the power’.
The ground is often called ‘Wednesbury unreasonableness’ in honour of the seminal judgment of Lord Greene MR in Associated Provincial Picture Houses Limited v Wednesbury Corporation [1948] 1 KB 223. However, judicial understanding of the ground has developed considerably since that decision: see Aronson and others, Judicial Review of Administrative Action (3^rd ed, 2004 Lawbook Co, Sydney) at 334-343. In Regina v Chief Constable of Sussex; ex parte International Trader’s Ferry Ltd [1999] AC 418 at 452, Lord Cooke of Thorndon noted the tautology involved in Lord Greene’s formulation of the ground. He expressed a preference for that adopted by Lord Diplock in Secretary of State for Education and Science v Tameside Metropolitan Borough Council [1977] AC 1014 at 1064: ‘conduct which no sensible authority acting with due appreciation of its responsibilities would have decided to adopt’. In a later case, Council of Civil Service Unions v Minister for the Civil Service [1985] 1 AC 374 at 410, Lord Diplock treated irrationality as a species of Wednesbury unreasonableness. He said Wednesbury unreasonableness:
‘applies to a decision which is so outrageous in its defiance of logic or of accepted moral standards that no sensible person who had applied his mind to the question to be decided could have arrived at it.’
It appears to be clear that, for Wednesbury unreasonableness to be established, it is not enough that the reviewing court has reached the conclusion that the statutory decision-maker erred, even seriously, in his or her assessment of the facts. Although the matter has been expressed in various ways in particular cases, a recurrent theme is that there must be something that, in effect, vitiates the decision-maker’s exercise of discretion.
In Peko-Wallsend at 42, Mason J likened the grounds set out in ss 5(2)(g) and 6(2)(g) of the ADJR Act to appellate review of a lower court’s discretionary judgment. His Honour said ‘a mere preference for a different result will not suffice’. He warned about the need for caution by a court ‘when reviewing an administrative decision on the ground that it does not give proper weight to relevant factors, lest it exceed its supervisory role by reviewing the decision on its merits’.
Similarly, in Chan v Minister for Immigration and Ethnic Affairs (1989) 169 CLR 379, all members of the High Court went to the trouble of identifying misconceptions by the original decision-maker, in deciding to uphold a case based on s 5(2)(g) of the ADJR Act: see Mason CJ at 389-390, Dawson J at 400, Toohey J at 408, Gaudron J at 416-417 and McHugh J at 431-435. That course was followed by McHugh and Gummow JJ in Re Minister for Immigration and Multicultural Affairs; ex parte applicant S20/2002 [2003] HCA 30; 198 ALR 59 at paras [67]–[69] (‘S20/2003’).
In S20/2003, Gleeson CJ at [5] paraphrased a comment made in Minister for Immigration and Multicultural Affairs v Eshetu (1999) 197 CLR 611 at 626 that ‘to describe reasoning as illogical, or unreasonable, or irrational, may well be an emphatic way of expressing disagreement with it’. His Honour went on:
‘If it is suggested that there is a legal consequence, it may be necessary to be more precise as to the nature and quality of the error attributed to the decision-maker, and to identify the legal principle or statutory provision that attracts the suggested consequence.’
Parramatta City Council v Pestell (1972) 128 CLR 305 (‘Pestell’) is an example of a case in which grounds of invalidity overlap. The High Court upheld a finding that a local rate was invalid. The authorising legislation empowered the council to impose such a rate where a work or service ‘would be of special benefit to a portion of its area to be defined as prescribed’. Menzies J thought this formula required correspondence between the land to which the execution of the work would be of special benefit and the land to be rated. He said at 322 that, if a council ‘could not, in reason’ find such a correspondence, the power was not activated. His Honour went on at 323:
‘The definition of the land that may be subjected to a local rate is determined by the council’s justifiable opinion of special benefit so that, if the so-called opinion could not be justified on any reasonable ground, then, the requisite opinion is lacking. There is, however, a world of difference between justifiable opinion and sound opinion. The former is one open to a reasonable man; the latter is one that is not merely defensible – it is right. The validity of a local rule does not depend upon the soundness of a council’s opinion; it is sufficient if the opinion expressed is one reasonably open to a council. Whether it is sound or not is not a question for decision by a court.’
Stephen J adopted similar reasoning. However, the other members of the majority treated the case as one of irrationality (Barwick CJ at 314) or Wednesbury unreasonableness (Gibbs J at 327). Common to all four judges was the view that the opinion the appellant council had in fact formed was one that was not reasonably open to it. In the language of Menzies J, it was not ‘a justifiable opinion’; that is, it was not ‘open to a reasonable man’.
The particulars of unreasonableness set out in para 4 of the applicants’ Points of Claim are as follows:
‘(a)The consequence of the Decision is an overall likelihood of one or more outbreaks of PMWS in Australia in the next ten years of between 96% and 99%, depending on the level of import trade that follows after the Decision.
(b)A conservative estimate of the likely consequences of an outbreak of PMWS in mainland Australia includes the spread of PMWS to 18% of Australian pig farms with more than 100 sows, with the following initial effects: reduced output in the Australian pig industry of $18.6 million; the loss of 59 full-time equivalent jobs in the industry and 52,000 livestock deaths; the loss of 180 full-time equivalent jobs across the economy; and reduction in Australia’s national output of $39.9 million.
(c)No reasonable person whose power to make the decision is qualified by an obligation to limit the level of quarantine risk to one that is “acceptably low” could make a decision which has such a risk of the introduction, spread and establishment of a new disease in Australia.’
The applicants have established the fact alleged in item (a). Because I rejected evidence of likely economic consequences (on the ground that this material was not before the Panel, the Director or Dr Carroll), the applicants have not proved the facts alleged in item (b). However, that does not matter if item (c) is made out. In relation to that item, it is necessary to bear in mind the distinction, drawn by Menzies J in Pestell, between a justifiable opinion and a sound opinion.
Most of the matters discussed above (use of annual risk, broad probability bands and the 50^th percentile and Table 8’s treatment of consequences) go only to the soundness of the Panel’s opinion as to the level of unrestricted risk. Essentially, the applicants say the Panel adopted a methodology and criteria that were likely to cause them to underestimate the level of quarantine risk stemming from a policy of issuing permits for the importation of pig meat from all countries, including those with PMWS affected herds. While I agree with the applicants’ criticism of aspects of the adopted methodology and criteria, it was for the Panel to determine both the manner of its assessment of risk and the level of risk that it was prepared to regard as ‘low’. The Panel did not exhibit any inconsistency or lack of logic in applying its selected methodology and criteria to the assessment of unrestricted risk.
The situation in relation to the conversion of unrestricted risk into restricted risk is different. As I have sought to explain, the Panel had no basis for the reasoning it adopted. Although I accept the Panel’s entitlement to make the judgment that the assumed infectious co-factor of PMWS was not likely to be more hardy than PCV2, the Panel did not know what would be the effect of its recommended restrictions in relation to reduction of PCV2 infection. If this had been a matter about which there was some scientific information, it would have been for the Panel to assess that information. It would not have mattered that the information was ambiguous or scientifically controversial and that the Court might have preferred a different view about it to that of the Panel. It would have been for the Panel to evaluate the information and to decide whether, and if so how, to use it in coming to its ultimate conclusions. However, that was not the situation in the present case. Here there was no information whatever; the necessary scientific research had not been done. The Panel had no material whatever upon which it could base a judgment that the assessed ‘low’ unrestricted risk would become ‘very low’, if its recommended conditions were applied to future permits.
Because of the absence of information, and logic, in the Panel’s final step, I think item (c) of the particulars is made out. This is not merely a case of an opinion that is unsound. The ultimate opinion formed by the Panel was unjustifiable in the sense explained by Menzies J in Pestell. I propose to uphold this ground of invalidity in relation to the IRA Decision (that is, the Director’s decision to adopt the IRAR, where the fatal flaw appears) and also in relation to the Permit Decision that was based upon the IRA Decision.
(d) no evidence
Paragraph (h) of each of s 5(1) and s 6(1) of the ADJR Act provides a ground of review ‘that there was no evidence or other material to justify the making of the decision’.
The applicants invoke this ground, giving the following particulars:
‘The Decision was based on the existence of a particular fact, namely, that current scientific knowledge permits the conclusion that measures which might be effective to reduce the risk of PCV2 (a virus already present in Australia) to an acceptably low level would be sufficient to do likewise in respect of PMWS (a disease not present in Australia) and any unknown disease agent involved in it. That fact does not exist.’
Subsection (3) of each of s 5 and s 6 of the ADJR Act is relevant to this ground of review. That subsection reads:
‘(3)The ground specified in paragraph (1)(h) shall not be taken to be made out unless:
(a)the person who proposes to make the decision is required by law to reach that decision only if a particular matter is established, and there is no evidence or other material (including facts of which he or she is entitled to take notice) from which he or she can reasonably be satisfied that the matter is established; or
(b)the person proposes to make the decision on the basis of the existence of a particular fact, and that fact does not exist.’
It will be noted from the particulars that the applicants rely on para (b) of subs (3). The question, therefore, is whether the Panel based their decision about risk management conditions upon the existence of the particular scientific knowledge identified in the particulars.
The IRAR does not say the Panel did this. Nor does the IRAR identify any scientific evidence, from mention of which an inference of reliance might be drawn. No affidavit or oral evidence of reliance was placed before the Court.
Having regard to those matters, it is not open to me to hold that the crucial final step of the Panel’s reasoning was based upon the existence of a particular fact, which fact did not exist. My conclusion that the IRA Decision (and so the Permit Decision) is unreasonable, in the Wednesbury sense, depends upon my finding that the final step in the Panel’s reasoning was unsupported by any fact, scientific evidence or scientific expertise. In other words, my conclusion depends upon a view of the situation that is the antithesis of what would be necessary for me to find before the ‘no evidence’ ground of invalidity would arise. Of course, if I am wrong in my reading of the IRAR, and it should be construed as indicating that the Panel did rely on scientific information, it might follow that I was also wrong about Wednesbury unreasonableness. In that event, it might be arguable that the ‘no evidence’ ground applies.
Disposition
In the usual course, I would immediately have turned to the question of relief, a matter upon which both parties have already made submissions. However, in deference to the request of counsel for the respondent, I will not take this course. I will publish these reasons and direct counsel for the applicants to send to my associate short minutes of their proposed orders, they first having discussed a draft of those orders with counsel for the respondent. If there is disagreement between the parties as to the appropriate form of orders, the respondent should also submit short minutes of proposed orders to my associate. After

receipt of the proposed orders, I will determine if it will be necessary to hear counsel further.

I certify that the preceding three hundred and seventeen (317) numbered paragraphs are a true copy of the Reasons for Judgment herein of the Honourable Justice Wilcox.
Associate:
Dated: 27 May 2005

Counsel for the Applicants: Mr J T Gleeson SC and Mr M J Leeming

Solicitor for the Applicants: Corrs Chambers Westgarth

Counsel for the First Respondent: Mr J Basten QC, Mr S J Gageler SC and
Mr G R Kennett

Solicitor for the First Respondent: Minter Ellison

The Second Respondent filed a Submitting Appearance.

Dates of Hearing: 8, 9, 10 & 11 November 2004

Date of Judgment: 27 May 2005

IN THE FEDERAL COURT OF AUSTRALIA
NEW SOUTH WALES DISTRICT REGISTRY	NSD 1078 of 2004

BETWEEN:	AUSTRALIAN PORK LIMITED FIRST APPLICANT WINDRIDGE FARMS PTY LIMITED SECOND APPLICANT
AND:	DIRECTOR OF ANIMAL AND PLANT QUARANTINE FIRST RESPONDENT FAYMAN INTERNATIONAL PTY LIMITED SECOND RESPONDENT
JUDGE:	WILCOX J
DATE OF ORDER:	27 MAY 2005
WHERE MADE:	SYDNEY

JUDGE:	WILCOX J
DATE:	27 MAY 2005
PLACE:	SYDNEY

Counsel for the Applicants:	Mr J T Gleeson SC and Mr M J Leeming
Solicitor for the Applicants:	Corrs Chambers Westgarth
Counsel for the First Respondent:	Mr J Basten QC, Mr S J Gageler SC and Mr G R Kennett
Solicitor for the First Respondent:	Minter Ellison
The Second Respondent filed a Submitting Appearance.
Dates of Hearing:	8, 9, 10 & 11 November 2004
Date of Judgment:	27 May 2005