Some Evidentiary Issues in Patent Law
Presentation to IPSANZ Conference
Minnesota Mining & Manufacturing Company v Tyco Electronics Pty Ltd  FCAFC 315; (2002) 56 IPR 248 may have had unintended consequences. The Full Court of the Federal Court's statement at  that "to give the Patent to a prospective witness is tantamount to leading the witness" needs to be understood in the context of the concerns about the evidence in that case as a whole. The problem was identified in the first instance judgment, Minnesota Mining & Manufacturing Company v Tyco Electronics Pty Limited  FCA 1359; (2001) 53 IPR 32, in which Sackville J made these points:
 The task of determining whether a claimed invention was obvious is inherently difficult, if only because of the pitfalls of having to place oneself in the position of a hypothetical skilled addressee at the priority date. Those pitfalls include the danger of misusing hindsight to which the authorities refer.
 A further difficulty is that, on some occasions, Tyco's experts were asked to address questions that were framed in general terms and not specifically directed to the criteria that must be used to determine whether a claimed invention was obvious….
The real issue is avoiding the effect of hindsight. The question of how that is best done, to the extent it can be done, is best determined on a case-by-case basis.
The rituals in which experts and lawyers in Australia currently engage to avoid hindsight are time consuming, expensive and may not achieve the objective of avoiding hindsight. Alternatives should be considered.
One possible approach is the development of a comprehensive set of standard instructions to experts on the law of inventive step.
Another is the use of early case management to facilitate agreement between the parties or determination of the factual information which may be provided to the experts and the questions the experts should be asked.
The art, the person skilled in the art, and the common general knowledge perform multiple functions in patent law.
What is the art?
The "art" is the subject-matter or field of the patent: Catnic Components Ltd v Hill & Smith Ltd RPC 183 at 235.
A patent may involve one or more fields. Identifying the field or fields of the patent is important because the person skilled in the art is the person with expertise in that area who is to be attributed with the common general knowledge of the relevant field or fields of the patent: JMVB Enterprises Pty Ltd v Camoflag Pty Ltd  FCA 1474; (2005) 67 IPR 68 at .
A degree of circularity of reasoning is involved as the field of the patent determines the common general knowledge and the person skilled in the art, and the field of the patent is to be derived from construing the patent through the eyes of the person skilled in the art.
Who is the person skilled in the art?
Identifying the person skilled in the art also depends on the field of the patent which is derived from the construction of the patent through the eyes of the person skilled in the art. The issue of circular reasoning again arises.
The person skilled in the art is one who is assumed to have a practical interest in the claimed invention and who wants to put the claimed invention to practical use: Catnic Components at 235; Stanway Oyster Cylinders Pty Ltd v Marks  FCA 527; (1996) 66 FCR 577 at 582.
The qualities of the person skilled in the art are affected by the nature of the field of the invention. If the field itself is practical and prosaic, the person skilled in the art would not be attributed with inventiveness. If the field is inherently inventive, the person skilled in the art may be attributed with the degree of inventiveness typical in the field.
Further, the extent of the common general knowledge of the person skilled in the art will depend on the field of the patent. If the field is complex and demanding and derived from multiple arts, the extent of the relevant general knowledge may involve the combined knowledge of multiple fields. This is commonly expressed as the person skilled in the art involving a notional team of persons with different kinds of expertise all of which it may be inferred from the patent have been brought to bear to reach the claimed invention: Root Quality Pty Ltd v Root Control Technologies Pty Ltd  FCA 980; (2000) 177 ALR 231 at .
The person skilled in the art does not hold perception beyond the knowledge and skill of the relevant field of the patent: Windsurfing International Inc v Tabur Marine (Great Britain) Ltd  RPC 59 at 71.Conversely, it must follow that the person skilled in the art does hold the perception, knowledge and skill of the relevant field of the patent.
What is the common general knowledge?
The common general knowledge is the knowledge which has been assimilated and accepted by the bulk of those in the relevant field, and includes the material and information to which such a person would have regard as a matter of course: Aktiebolaget Hässle v Alphapharm Pty Limited  HCA 59; (2002) 212 CLR 411 at , ; Re Raychem Corp's Patents  EWHC 372;  RPC 31 at .
What is the motivation or state of mind of the person skilled in the art?
The person skilled in the art is not attributed with qualities such as "constitutional idleness": Windsurfing International at 71.
But nor are they to be assumed to be motivated to solve a problem which the evidence, be it the terms of the patent or other evidence, does not establish was recognised to be a problem at the priority date.
That is, recognition of the problem the patent is said to solve cannot be assumed away as a potential inventive step unless the terms of the patent and/or the other evidence about the common general knowledge in the field(s) of the patent disclose that the problem itself was known to those skilled in the art before the priority date.
In this regard while the prior art base and the common general knowledge are used to "look forward from the prior art base to see what the skilled person is likely to have done when faced with a problem similar to that which the patentee claims to have solved with the claimed invention" (AstraZeneca AB v Apotex Pty Ltd  HCA 30; (2015) 257 CLR 356 at  per Kiefel J (as her Honour then was)), the issue whether a person skilled in the art was "faced with a problem similar to that which the patentee claims to have solved" is a matter for evidence, not assumption. The perception of a problem may involve or be part of an inventive step: Lockwood Security Products Pty Ltd v Doric Products Pty Ltd (No 2)  HCA 21; (2007) 235 CLR 173 at  and ; Alphapharm at  citing Aickin J in The Wellcome Foundation Limited v VR Laboratories (Aust) Proprietary Limited  HCA 12; (1981) 148 CLR 262 at 280–281.
What functions do the art, the person skilled in the art and the common general knowledge perform?
First, patents are construed through the eyes of the person skilled in the art who is attributed with the common general knowledge in the field of the patent.
Secondly, the prior art base documents/information are construed and understood through the eyes of the person skilled in the art for the purposes of assessing novelty and inventive step.
The role of evidence
Apart from the terms of the patent itself, everything discussed above – the art, the field(s) of the patent, the person skilled in the art, the qualities and extent of the knowledge of the person skilled in the art, the existence of any problem to be solved and the motivation of the person skilled in the art to solve the problem, and the common general knowledge (all as at the priority date) – are all matters for proof by evidence.
The significance of this observation – that proof by evidence is required of all these matters – cannot be overstated.
The patent area
The patent area in the Patents Act 1990 (Cth) means, in substance, Australia: s 3 and Sch 1.
Before the amendments introduced by the Intellectual Property Laws Amendment (Raising the Bar) Act 2012 (Cth), the patent area dictated the content of the common general knowledge and the application of the test for inventive step. This is because the test for inventive step in s 7(2) referred to the common general knowledge as it existed in the patent area before the priority date.
On this basis, it was commonplace for the patent and the prior art base information to be construed through the eyes of the person skilled in the art in the field of the patent armed with the common general knowledge in the patent area (Australia).
Since the Raising the Bar amendments, s 7(2) provides that the test for inventive step involves the common general knowledge as it existed whether in or out of the patent area before the priority date.
Observations on evidence
The avoidance of hindsight
Following Tyco, an issue which is the subject of painstaking attention by the lawyers involved in the preparation of expert reports or affidavits is that the evidence of the expert not be affected by hindsight.
Avoiding the effect of hindsight reasoning is critical. I do not trivialise the nature or extent of reasoning errors that hindsight can cause.
The concern is that the rituals we have adopted to protect against hindsight reasoning in patent cases involves a multi-layered problem, probably most acutely experienced by the experts who are subjected to (and must be bewildered by) the ritual.
Layer one is that the rituals may not protect against hindsight reasoning.
Layer two is that we may think that if we adopt the rituals, we have protected against hindsight reasoning, so the expert's (and our own) guard is down.
Layer three is that in performing the rituals we may overlook other techniques which might be more effective in protecting against hindsight reasoning, including fully and properly instructing experts about the person skilled in the art, the common general knowledge, the test of obviousness, what hindsight involves, why hindsight reasoning is impermissible, and the consequential need to avoid hindsight.
Layer four is that, with no justification of which I am aware, the whole process assumes that experts (who actually hold relevant expertise in the field) are incapable of doing what is humanly possible to put hindsight to one side, but judges (who hold no expertise in the relevant field and therefore do not even know what it is that they do not know and who see everything before deciding on the issue of inventive step) have some super-human capacity to do so.
The ritual of "sequential unmasking" (Akebia Therapeutics Inc v FibroGen, Inc  EWHC 866 (Pat) at ) to avoid hindsight is well-known.
First, the expert must be engaged. In being engaged, however, the expert must not be told what the claimed invention is or what the patent is for. At most, the expert may be told the general field of the patent (presumably, something the expert could have worked out for themselves given that they would assume they are being retained because they hold relevant expertise).
Why is this first step undertaken in this way? It is because if the expert sees the patent, and therefore knows what the invention is, their mind will be infected by hindsight when the expert comes to assess whether or not the invention was obvious when compared to the prior art base at the priority date.
Hindsight bias is a well-documented psychological phenomenon. It is defined in the American Psychological Association Dictionary of Psychology as:
the tendency, after an event has occurred, to overestimate the extent to which the outcome could have been foreseen. Hindsight bias stems from (a) cognitive inputs—people selectively recall information consistent with what they now know to be true; (b) metacognitive inputs—people may misattribute their ease of understanding an outcome to its assumed prior likelihood; and (c) motivational inputs—people have a need to see the world as orderly and predictable.
Other areas of law recognise hindsight bias, but none that I know suggest that an expert giving evidence in the case cannot know the subject-matter of the case other than by degrees or is expected to give evidence progressively from a time when the expert purportedly knows nothing to a time when the expert (at last) has seen the patent in dispute.
In other areas of the law it is expected that an expert will give evidence once they know the relevant facts. It is expected that the expert will be able to recognise and, so far as humanly possible, eliminate the heresy of hindsight. It is expected that cross-examination will expose an expert who has succumbed to the heresy to any material extent. It is also expected that the judge, who will be writing a judgment and hearing evidence having seen the patent, will be able to assess the extent to which the expert may have succumbed to the heresy of hindsight and weigh their evidence accordingly.
And as foreshadowed above, why is it assumed that a judge's brain is somehow capable of immunising itself from the hindsight heresy, but an expert's brain is not? After all, it is the judge who ultimately determines all of the issues of fact and law, and the judge does so knowing all of the evidence including all details of the invention. Why do we assume that a properly instructed expert in the field (including proper instruction as to the need to avoid hindsight bias) does not have the same (imperfect) intellectual flexibility as the judge? If anything, expertise in the field might make an expert better at recognising the effects of hindsight than a judge. And even if the expert's opinions are affected by hindsight, why do we assume that the adversarial process will be incapable of exposing the effect and its significance for the expert's opinions? That is, ultimately, it is the judge who needs to allow and account for the unavoidable effects of hindsight as best they can, but it would help if the expert was as aware as the judge of the need to avoid hindsight as far as humanly possible. Standardised comprehensive instructions to experts about the law of inventive step might assist in this regard and weaken the perceived incentive of engaging in the current rituals.
Secondly, once the expert is engaged, the lawyer and expert must engage in a ritualised dance in which the expert must pretend they don't know why they are being retained and the lawyer must do nothing to undermine the maintenance of that pretence. The lawyer can reveal the relevant field of expertise, but it might be imagined the expert could work this out for themselves given the fact of the retainer. The lawyer cannot reveal the issue which the expert is being asked to address – ie, (1) was this invention obvious at the priority date, and (2) was this invention novel at the priority date.
Instead, and thirdly, the expert must be asked to identify the common general knowledge at the priority date in the area without knowledge of the invention. In some cases, where the patent dispute is notorious, this exercise is entirely fictitious. In others, where the expert truly does not have a clue what the invention is, the exercise can be less than helpful because it lacks focus. Experts have so much common general knowledge that they cannot be expected, without some direction, to expose the relevant common general knowledge.
Fourthly, having identified the common general knowledge, the expert can be asked to undertake an exercise intended to mirror the inventor's journey but without actually knowing what the invention is. This will raise the fraught issue as to whether the problem overcome or the advance made by the invention either formed part of the common general knowledge or was itself part of the inventiveness of the invention. If the latter, it is difficult to see how the expert could legitimately perform the exercise without being given further information relevant to the invention which will lead to the charge of hindsight infection.
Fifthly, if the Raising the Bar Act amendments apply, the expert might also be given the prior art information and asked if the invention was novel at the priority date in light of that information.
Sixthly, the expert might at last be given the patent and be asked to opine if the claimed invention was obvious in light of the common general knowledge at the priority date.
The potential problem with this ritual is that it usually breaks down at some point – either because the invention and/or the patent dispute is notorious, or because to elicit relevant information the expert is or has to be given more information at some point which can then be said to have infected the evidence with hindsight. This can lead to cross-examination about a peripheral issue (what did the expert know when) and credit issues can arise (the expert saying they did not have something in their mind but they actually did etc). None of these issues are directly relevant to the patent dispute but they can take time to resolve and distract from the key issues in dispute.
Part of the ritual might have made some sense when s 7(3) of the Patents Act 1990 (Cth) applied prior to the Raising the Bar amendments, ie, when prior art information for the purpose of inventive step had to be information that the skilled person at the priority date would be reasonably expected to have ascertained, understood, and regarded as relevant. When this version of s 7(3) applied, the approach taken was that the question was best answered by an expert identifying what information they would have ascertained, understood, and regarded as relevant by performing that exercise as if it were being undertaken at the priority date. Again, however, the artificiality of this exercise means that it usually broke down at some point, leading to time being taken up with issues not directly relevant to the patent dispute.
The artificial nature of the ritual is reinforced by the selection of experts. The understandable tendency of a litigation lawyer is to retain the best, most renowned experts in the field. But the knowledge (and inventive capacity) of these experts might be far removed from the person skilled in the art. The greater the knowledge of the expert, the more they might have to disregard as not forming part of the common general knowledge at the priority date. Without detailed and explicit instructions, this is a strange position for an expert to be put in. They are being retained because they are renowned in the field, but the evidence being sought from them is not evidence of their own knowledge and capacities and what they could have invented – what is sought is their opinions about what effectively everyone in the relevant field would know and take as given. If such a person is retained as an expert, then they need to understand in detail what evidence they can give which is relevant. This indicates that proper instructions to the expert about the law of inventive step are critical.
The value of the ritual?
Overall, I remain to be persuaded that there is real value in the ritual. It may even be that because the ritual is intended to protect the evidence from hindsight, the expert is not as attuned to the invidious effect of hindsight as the expert otherwise might be if fully and properly instructed about the person skilled in the art, the common general knowledge, the test of obviousness, what hindsight involves, why hindsight reasoning is impermissible, and the consequential need to avoid hindsight.
Nor do I think the process shields the expert from challenges to credit. To the contrary, maintaining the pretence at all costs that the expert has not been infected by knowledge of the invention (eg, because an embodiment has been marketed and is well-known by the time the patent case appears), at least in my experience, provides fertile ground for credit challenges.
Justice Birss (as he then was) made the same points more succinctly in HTC Corporation v Gemalto S.A.  EWHC 1876 (Pat);  RPC 257 at – in these terms:
…approaches like this are servants and should not become elevated into masters. The approach can risk creating a number of potential difficulties. First the expert naturally may think there is a legal requirement that this be done and that somehow a breach of this protocol is wrong or is his or her fault. There is no legal requirement that expert evidence in patent cases must be given this way. It will not always be fair on the expert to place this burden on them. Second, many patent lawyers are highly skilled at presenting information to the expert which, consciously or subconsciously, has the effect of leading the expert to the conclusion sought. Neither the expert nor the legal team may be aware of it at all. The expert may genuinely think they have formed views without knowledge of the contents of the patent when in fact they may have been led there. Thus the approach may not in fact eliminate hindsight and is capable of giving a false impression.
The exercise in this case caused much more trouble than it could ever have been worth.
Similar observations were made in Fresenius Medical Care Australia Pty Ltd v Gambro Pty Ltd  FCAFC 220; (2005) 224 ALR 168 at  where Wilcox, Branson and Bennett JJ said:
In coming to his conclusion on obviousness, his Honour was mindful of the restraint imposed by the artificial exercise engaged in by Dr Davies and of the alternative problem of a witness attempting to give evidence of the obviousness idea when he or she already knew the answer. This is particularly acute where the inventive step involved an idea which, once appreciated, was implemented by the application of well-known principles. That is not to say that such evidence should be disregarded but it makes it more difficult to allow for 'the insidious effects' or 'misuse' of hindsight. This problem has long been recognised in patent cases. It is but one matter for the judge to take into account in weighing the evidence of the witnesses, as was the inventiveness of the witnesses (at ), the passage of time since the priority date (at ) and the provision of prior art which was not part of common general knowledge (at  and –). Other factors were the level of advocacy engaged in by the witnesses and the relative levels of skill each possessed. None of these matters is determinative; each is relevant to the assessment by the judge of the competing evidence on obviousness in the circumstances of this case.
My suspicion is that we materially underestimate the reality of the telegraphing of the problem and the solution to experts throughout the process of the preparation of evidence and materially over-estimate the likelihood of a lack of hindsight if evidence of such telegraphing is not apparent.
As a matter perhaps of personal disposition, I tend to favour a direct approach in which all pretence is abandoned, at least in a case where the reality is that the experts know what the invention is even if they cannot be told that by the lawyer. If all pretence is abandoned, then the experts and the courts can acknowledge and make allowances for the inevitable impact of hindsight.
Approved standard instructions to experts?
To assist this, I also raise for consideration the possible development of a court-approved comprehensive standard set of detailed instructions to be provided to experts about the person skilled in the art, the common general knowledge, the test of obviousness, what hindsight involves, why hindsight reasoning is impermissible, and the consequential need to avoid hindsight. I am aware of one set of standard jury directions about obviousness in the US District Court (Northern District of California), but not of any standard expert witness directions for obviousness. Even in cases where the ritual of sequential unmasking is agreed to be of overall benefit, standardising the directions to experts about these issues may be worth the investment of resources it would require.
I also raise for consideration the use of early case management to facilitate agreement between the parties or resolution of the factual information which may be provided to the experts and the questions the experts should be asked.