How do you protect patents from judicial and expert hindsight?

The Hindsight Glasses gave Merpel the
power to see that all inventions
were obvious
Oh, hindsight...a wonderful thing.  Unless, of course, you are patentee.  A couple of Tuesday evenings ago, when it was still brutally cold in London, Dr Siva Thambisetty, Associate Professor of Law at the LSE, hosted a seminar which was cryptically titled “Inventive Step in the UK and Use of Experts in Patent Litigation”.  Rachel Mumby (Bristows) reports on the event:  
"All that attendees knew before the event was that the intention was to “explore the cognitive burden and mechanics of litigation strategies on inventive step”.  
After a mad dash from the office, several attendees could be found wandering the halls of the LSE searching for the correct room, because all they could find was a room with large numbers of people seemingly doing an exam. In fact, that room was the correct place to be, because the evening started with all participants being handed some papers to read, including a patent litigation scenario and short expert report (prepared by Alan Johnson of Bristows). Participants were then asked to answer a series of online questions, including what they thought the likelihood was of the patent in suit being held to be obvious. Participants were also warned not to confer with their comrades as not everyone had the same information. So, after a certain amount of huffing and puffing about being required to think, participants settled down to the task in hand. 
After the survey had been completed, Dr Thambisetty explained that the survey was part of research being done in relation to hindsight bias and blinding in the assessment of obviousness, for example looking into the probative value of blinding and whether it can affect litigation outcomes. She also introduced Prof Christopher Robertson of the University of Arizona who is leading this study. 
Prof Robertson then took to the floor and gave a fascinating presentation on hindsight bias, noting that over 800 papers have been published on the topic (across many different fields, not just patents). The audience learned that hindsight bias is very much part of human nature. Further, this issue is not restricted to mere mortals, but experts and judges have the same problems (and sometimes worse). It has been psychologically proven that once we know that a particular event has happened (e.g. an invention has been made), the facts which previously pointed away from that event happening become harder to remember. What’s more, there is no strong evidence to suggest that any of us can reliably channel our mind to avoid hindsight bias – we cannot help ourselves. This is why blinding (and particularly double-blinding) is so important in clinical trials and also, for example, police line-ups. 
Next Dominic Adair (Bristows LLP) complained very politely about the steps which, following MedImmune v Novartis, patent litigators take to try to minimise hindsight bias when working with experts. He discussed the great time and cost which is incurred in discussing the CGK and then the prior art, often with multiple prospective experts, before they can be shown the patent and it can be determined whether they will be suitable for that case. In particular, he noted that for a party surprised by receiving an infringement action it is almost impossible to complete this process in the 6 weeks between being sued and needing to file Grounds of Invalidity citing particular pieces of prior art. Further, in some cases experts are needed to assist with assessing a potential infringement, and this work has to be carried out before the other side has cited any prior art. In other cases it may be clear from the outset what the patented technology will be, making the staged approach something of a farce. Indeed, in circumstances where the invention exists in identifying that there is a problem, it can be incredibly difficult to frame the discussion without discussing the shortcomings in the state of the art. What happens if new prior art is cited during the proceedings? Can solicitors and barristers not be trusted to educate experts on the dangers of hindsight bias and seek to avoid this?

Anna Edwards-Stuart (11 South Square) then took up the microphone and provided the alternative view. She reminded the audience that patent law, in particular the concept of the person skilled in the art, is inherently artificial. Experts rarely personify the person skilled in the art and can only test their views against their own experience. This means that without steps, such as sequential unmasking, being taken to try to avoid hindsight bias, the expert becomes vulnerable on cross-examination.

Citing Arnold J’s comments in American Science v Rapiscan, Anna also noted that care still needs to taken with sequential unmasking. Further, bias does not only crop up when documents are read in a particular order, hindsight bias can also arise if experts are instructed to focus on one passage of the prior art to the exclusion of others, or where elements of the CGK are cherry-picked to form a CGK attack. She concluded that the most important thing is that it is made clear in expert evidence how the expert has been instructed, what opinions he/she gave when, and that the basis for any opinions given are carefully explained.

Next came the analysis of the results of the survey. The audience were told that half of the room had read expert reports which made it clear the steps that had been taken by the expert to avoid hindsight bias (for example the order that documents had been read in) and half had not. Interestingly, the results were the opposite of those expected, but this may be down to the small sample size and slightly rushed nature of the exercise. Interestingly, one clear message was that participants thought that blinding is valuable but not practical in patent litigation. 
The evening concluded with comments from Arnold J and Dr. Matthias Zigann (presiding judge of the Munich Regional Court), and also some emailed observations from Birss J (who was unable to attend).

Arnold J noted that the literature is conclusive that experts are no better than lay people at avoiding hindsight bias, and that telling someone to avoid hindsight does not work. He suggested that experts being blinded as to which party is instructing them is one way of avoiding some bias, but that does not avoid hindsight bias. He went on to observe that there is a breadth of literature which shows that linear unblinding, and reaching conclusions at each stage of the process is helpful. However, he stated categorically that this is not compulsory when instructing experts, and accepted that it can be costly and can in certain circumstances be an impossible approach. Having said that, he also observed that in the Courts of England and Wales we place considerable weight on expert evidence, and if we are to continue to do so, we need that evidence to be as high quality as possible, which should make the parties want to ameliorate potential weaknesses such as hindsight bias. (In other words, you don’t have to do it, but on your head be it if you don’t and could reasonably have done so.) 
He also observed that as Judges are not immune to hindsight bias either, it is helpful to know that experts have been instructed linearly. Further, as hindsight bias produces an asymmetric effect, tending to favour the party seeking to invalidate a patent, Judges should lean the other way to try to compensate for this. 
He concluded by picking up on a point raised by Anna Edwards-Stuart, that patent law is grounded in hindsight – it is legally routine for prior art to be selected with hindsight, but this does not mean that nothing should be done about bias when assessing obviousness. 
Although unable to attend, Birss J had already provided some views on the subject (which he knew to be at odds with those of Arnold J). In an email which was read out by Dr Thambisetty, Birss J opined that: 
  1. The concept of blinding in patent litigation is fundamentally flawed.
  2. The role of experts is to educate the Court, not to come to conclusions on obvious, or be used like an experiment to test whether or not something is obvious. Therefore, blinding of experts is unnecessary.
  3. If blinding is to be used, single blinding is not sufficient – to be effective double blinding is required (i.e. legal teams mustn’t know which side they are on). Indeed, in his view lawyers sometimes knowingly or subconsciously lead their experts towards particular conclusions by the nature of the questions they ask.
  4. If experts are to be blinded, then judges also need to be blinded and to read documents in a particular order, giving their opinions along the way.
  5. Experts are almost always more skilled than the “person skilled in the art” so does analysis also need to be done on how much more skilled they are in order to assess their blinded opinion? 
Dr. Zigann then provided a German viewpoint, which appeared to be that experts, and more particularly party experts, are unnecessary. He argued that experts are not needed to determine obviousness as this is a matter of law. Further, if the only thing the expert contributes is an explanation of the technology, then this can be done by lawyers, or if necessary, with a court appointed expert (court appointed experts have some of the same hindsight bias issues as party experts, but they may not be exposed to other types of bias).

The evening concluded with an acknowledgement of the fact that at least hindsight is not as inherent in the English system as it is at the EPO where hindsight is an inevitable part of identifying the closest prior art, and where the problem to be solved is formulated from that closest prior art.

The broad consensus was that it was a captivating and thought provoking evening. It is clear there is no ideal solution, but those present enjoyed the opportunity to learn a little more about this topic which is so fundamental to the way many cases are run."
How do you protect patents from judicial and expert hindsight? How do you protect patents from judicial and expert hindsight?  Reviewed by Annsley Merelle Ward on Thursday, March 29, 2018 Rating: 5


  1. Not only can "double-blinding" for attorneys never work, it would be unethical to attempt to do so (zealous advocacy and informed consent and all).

  2. Excellent topic which, I hope, stimulates a long thread of informed comments.

    Can I kick off by distinguishing between "hindsight" and "ex post facto" analysis.

    You cannot shut out hindsight. It is futile to suppose that you can. Once I've acquired "hindsight" knowledge of the invention, I cannot magic it away.

    But you can shut out ex post facto analysis. That's what the EPO's Problem and Solution Approach does.

    And so I resent it, that people dismiss EPO-PSA as "tainted with hindsight". The way I see it, it is "real world" and, more than that, the only way to "do" obviousness fairly and economically, in a way that justice is not only done but seen (by persons skilled in the art, and business people) to have been done.

    But of course, what chance does a mere Patent Office have, of establishing a fair way to decide obviousness, against the massed ranks of judges and litigators, in both the common law and civil law worlds, who choose not to inform themselves properly about EPO-PSA and so remain ignorant of how EPO-PSA works in practice.

    So come on, all you litigator readers, try your hand at rubbishing the EPO Approach. Robin Jacob tried, but his efforts were lamentable despite his elevated reputation. Anybody here fancy accepting the challenge?

    An incidental result of any such debate will be to expose enduring gaps of understanding, between lawyers in common law jurisdictions (eg England) and those in civil law jurisdictions (eg Germany). The floor is yours.

  3. Readers, in this context, I commend to you the piece on how to judge obviousness, just published in VPP Rundbrief 1/2018 and authored by German Supreme Court patents Judge Deichfuess.

    He tells us that obviousness is a question of law, so he will decide it in his court, reversing the lower court whenever he feels like doing so.

    All those of you who are European patent attorneys, readers who have studied the "White Book" of the established caselaw of the EPO on obviousness, read Deichfuess and weep about the difficulties you face, to opine to a client on the issue, whether a court in Germany will hold your claim obvious. Or not, as the case may be. Before Lord Justice Deichfuess. You need a crystal ball of course, unless you can read his mind without it.

    And then get angry with all those who would destroy the brilliant caselaw-making ability of the EPO, to clear the way for the limping progress towards an EU obviousness court. You know what I mean: the EPO-PSA analysis that brings a strong degree of predictability and legal certainty to deciding obviousness.

  4. And yet another comment. This:

    "The evening concluded with an acknowledgement of the fact that at least hindsight is not as inherent in the English system as it is at the EPO where hindsight is an inevitable part of identifying the closest prior art, and where the problem to be solved is formulated from that closest prior art."

    I cite as an example of litigators everywhere agreeing with each other, in mutual self-interest, to diss EPO-PSA. As usual, readers, follow the money.

    That hindsight is "inherent" in EPO-PSA is not a legitimate criticism. Consider: it is with 20/20 "hindsight" of i) the invention and ii) the published prior art, that a patent attorney carefully drafts the patent application which is going to serve as the basis of deciding whether the claim is obvious. The inventor/Applicant/drafter gets to choose i) the technical field and ii) the inventor's "problem" and iii) what technical effects the claim delivers. All relative to prior art, if not already known and understood by the drafter then ought to have been known. The invention thus arrives at the Patent Office, bright-eyed, bushy-tailed, dressed up and "spun" in the best possible light.

    And where is the public interest in all this? What is so "Flawed" about a way of examining obviousness that gives Applicant full faith and credit for every word of the specification of the patent application, but then coolly subjects it to a sceptical scrutiny, that involves no iota or scintilla more "hindsight" than the drafter had when writing the petition to the Patent Office?

    Equality of arms, I say.

  5. The lady doth protest too much, methinks.

  6. "All relative to prior art, if not already known and understood by the drafter then ought to have been known."

    Ought to have been known?

    Pure fallacy.

  7. comments into the aether?


  8. Not only can "double-blinding" for attorneys never work, it would be unethical to attempt to do so (zealous advocacy and informed consent and all).

    Yes, I think that was the point.

    Ms Edwards-Stuart is on the right track, the expert can no more be expected to assume the mantle of the skilled person than can the judge or legal professionals. It has never sat well with me that there is some 'correct' order in which papers might be revealed to them so as to remedy this fundamental artifice. Better that experts are instructed in a way best suited to the time available and with regard to the overriding objective. Judges are well qualified give testimony its appropriate weight, and read it in the light of the context in which it is given.


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