If there was ever a need for authority for the proposition that what an applicant says or writes is still ‘evidence’, and that there is no legal requirement for evidence to be corroborated before it can be accepted (and the increasing trend in Tribunal and IAA decisions suggests there is such a need), see NAKD v Minister for Immigration & Multicultural & Indigenous Affairs  FCAFC 321 per Hill J at .
A particularly egregious example of unreasonableness is Abboud v Minister  FCA 185 in which the Tribunal made arbitrary assumptions as to how a gay person ought to behave. The Tribunal has now on several occasions rejected persecution claims on the basis of sexuality through means of suggesting the applicant is involved in a gay ‘conspiracy theory’. Patently, such approach is unreasonable, irrational or demonstrative of failing to engage with the material before it. The entire Abboud decision is worth reading in order to expose the audacity of the Tribunal’s reasoning, but see especially -.
Frequently a decision-maker will leap to a conclusion that an applicant has been ‘inconsistent’ in his or her account. Frequently also, a decision-maker will bandy this label of ‘inconsistency’ incorrectly.
Often, in truth something may not be ‘inconsistent’. For example, the omission of making a particular claim at interview 1 does not mean it is an ‘inconsistency’ if raised in interview 2: see AVQ15 v Minister  FCAFC 133 at .
Also, just because there is an ‘inconsistency’ (assuming that word is used correctly), it does not follow that a credibility issue emerges. For example, a minor inconsistency cannot be transformed into a reason to disregard the whole of an applicant’s claims: see AVQ15 v Minister  FCAFC 133 at ; Minister for Immigration and Citizenship v SZRKT  FCA 317; 212 FCR 99 at .
Further, special attention needs to be given to the circumstances in which an applicant is giving evidence, before leaping to a conclusion of ‘inconsistency’ (or for that matter, adverse credit). Thus, if an applicant warns that he or she is only giving a ‘summary’ which is ‘not an exhaustive statement’ and will be giving more detail at a later stage, a failure to appreciate that qualification may create a jurisdictional error: see AVQ15 v Minister  FCAFC 133 at , , , .
The proposition that representations in relation to a s 501 cancellation attempt are not ‘mandatory relevant considerations’ is highly doubtful if not at least reductionist. See the discussion in Viane v Minister  FCAFC 116 per Rangiah J - and Colvin J at -. What matters is (or perhaps a better characterisation than ‘mandatory relevant consideration’ is) whether the relevant aspect which was not considered could amount to a ‘representation’, in which case it must be considered.
See also Hay v Minister  FCAFC 149 per Colvin J.
As to what is required to show that there has been a consideration, see Minister for Immigration and Border Protection v Maioha  FCAFC 216 at :
What is required is the reality of consideration by the decision-maker. On judicial review the Court must therefore assess, in a qualitative way, whether the decision-maker has as a matter of substance had regard to the representations put: compare Fraser v Minister for Immigration and Border Protection  FCA 1333 at  per Perram J. Additional adjectives do not assist that analysis and indeed tend to distract from it by being “apt to encourage a slide into impermissible merit review”: Minister for Immigration and Citizenship v SZJSS  HCA 48; 243 CLR 164 at  citing Swift v SAS Trustee Corporation  NSWCA 182; 6 ASTLR 339 at . Because the Court must make its own qualitative assessment, the fact that a decision-maker says they have had regard to a representation does not by itself establish that they have, as a matter of substance, had that regard. Neither does the Court ignore such a statement.
In Carrascalao v Minister  FCAFC 107 the Court inferred that the Minister did not actually consider the material he was obliged to, before making his formulaic decision. The judgment discusses two cases in which the evidence showed that the Minister had at most about half an hour to consider hundreds of pages of material, which of course, he would not have done in that time.
The error was failing to give proper, genuine and realistic consideration to the merits of the cases. The Full Court explained:
129. … 43 minutes represents an insufficient time for the Minister to have engaged in the active intellectual process which the law required of him in respect of both the cases which were before him.
The Minister was also the subject of a Jones v Dunkel inference arising from the failure of one of the central characters, his Chief of Staff, to give any evidence:
130. Seventhly, the inferences which we have drawn from the material above in concluding that the Minister did not engage in the requisite active intellectual process, is reinforced by the fact that neither he nor his Chief of Staff gave evidence. Accordingly, we would apply the principle in Jones v Dunkel  HCA 8; 101 CLR 298 which, we note, was also applied in the particular circumstances in the Douglas case at 61-62 and in other judicial review cases referred to therein. As the Full Court observed in the Douglas case at 62:
The application of the rule requires… that there be inferences available from the evidence which favour the other party. The failure of the Minister to call evidence does not provide positive evidence that he did not consider the representation but, unexplained, it leaves the Court in a position where opposing inferences can be more confidently drawn because they stand uncontradicted by the person who could say something about the true state of the facts: Jones v Dunkel at 308. The question then is what inferences were open on the evidence.
131. In considering whether the rule of evidence in Jones v Dunkel applies here, we have taken into account the multiple statements made by the Minister in his statement of reasons to the effect that he had considered, noted, accepted, recognised or had regard to various matters, as well as the concluding statement which appears in both statements of reasons that the Minister had “given full consideration to all of the information before me in this case” (emphasis added). The Minister may subjectively have believed these matters, including his claim to have given full consideration to all the information before him in both cases but, for the reasons set out above, we do not consider that his subjective belief is determinative when, for the reasons given above, the Minister did not have sufficient time to engage in the active intellectual process required by law before deciding to cancel the two visas.
 Surprisingly little judicial attention has been devoted to the concept of an “integer” of a claim, as that phrase was coined in Htun. That may explain why in 2013 Robertson J in SZRKT took the view that the authorities illuminated no clear distinction between “claims” on the one hand and “mere” items of evidence on the other. The phrase “integer” seems to have been used interchangeably with “component of claim” (Htun) yet in Tran v Minister for Immigration and Multicultural and Indigenous Affairs (Kiefel, RD Nicholson and Downes JJ) the opportunity for exposition was not taken up as the Full Court of the Federal Court of Australia merely stated that the tribunal was “required to deal with all integers of an applicant’s claim”, without providing elucidation about what an integer was. His Honour Judge Manousaridis has held that an “integer” may be taken to be the equivalent of a material question of fact. His Honour so held in SZURJ v Minister for Immigration and Border Protection that an integer was a meaningful subset of material questions of fact, which, in combination with other meaningful subsets of material questions of fact, ought to lead the Tribunal to conclude in a particular way. In my respectful view, his Honour’s consideration of the subject is accurate. It appears to be one of the only statements of principle on point. The sheer volume of decided migration cases in the federal jurisdiction over the last 10 years has overtaken observations in learned writings of the early millennium of which an example is Caron Beaton-Wells, ‘Judicial Review of Migration Decisions: Life After S157’. So far as my research has uncovered, the consideration given to the subject of integers by his Honour Judge Manousaridis is the best and only treatment on the point.
See Craig v The State of South Australia (1995) 184 CLR 163 esp at 179-180:
[T]he ordinary jurisdiction of a court of law encompasses authority to decide questions of law, as well as questions of fact, involved in matters which it has jurisdiction to determine. The identification of relevant issues, the formulation of relevant questions and the determination of what is and what is not relevant evidence are all routine steps in the discharge of that ordinary jurisdiction. Demonstrable mistake in the identification of such issues or the formulation of such questions will commonly involve error of law which may, if an appeal is available and is pursued, be corrected by an appellate court and, depending on the circumstances, found an order setting aside the order or decision of the inferior court. Such a mistake on the part of an inferior court entrusted with authority to identify, formulate and determine such issues and questions will not, however, ordinarily constitute jurisdictional error. Similarly, a failure by an inferior court to take into account some matter which it was, as a matter of law, required to take into account in determining a question within jurisdiction or reliance by such a court upon some irrelevant matter upon which it was, as a matter of law, not entitled to rely in determining such a question will not ordinarily involve jurisdictional error.
See also discussion in SZVDC v Minister for Immigration and Border Protection  FCAFC 16 in the context of applications under s 39B of the Judiciary Act in relation to a Federal Circuit Court judge’s refusal to extend time under s 477 of the Migration Act.
See the discussion about proportionality and the exercise of particular kinds of power, by Barker J in his speech http://www.fedcourt.gov.au/digital-law-library/judges-speeches/justice-barker/barker-j-20140725.
The test and authorities discussing factual permutations are discussed by Kenny J in VFAB v Minister for Immigration & Multicultural & Indigenous Affairs  FCA 872.
It is whether a fair-minded lay observer might reasonably apprehend that the Tribunal member might not have brought an impartial mind to the resolution of the question to be decided.
A particularly outrageous example is found in S233 of 2002  FMCA 39. See for example:
 It is also noteworthy that on that same page, at about point nine, that the turn that emerges from the text of the Tribunal members’ questioning of the applicant is, to say the least unfortunate, bearing on the sarcastic and I quote:
How can they possibly distribute these dissident leaflets in parks and cafes? How can that possibly happen? Do they walk around to people having picnics and say ‘will you please read this’? Do they interrupt someone in the middle of bowl of pho and say ‘Oh excuse me, just while you are having your pho would you please read this pamphlet’.
See obiter remarks entitled ‘Disturbing undercurrents’ by Flick J in Minister for Immigration and Citizenship v SZQRB  FCAFC 33.
See also - for a discussion about how personal non-compellable powers which may be exercised in the ‘public interest’ must still take into account relevant factors. It is an error to make a decision ‘irrespective of’ relevant factors: