The proper role of expert evidence

The decision in UbiPark v TMA Capital Australia[1] provides some useful commentary on the role of expert witness evidence in a patent infringement and revocation action.

Moshinsky J, referenced various authorities at [55] to [63] on the principles of construction of a patent and the role the expert witness plays in that exercise. At [59] his honour noted that an expert witness cannot assist the court with the meaning of an ordinary English word (or phrase) unless it has a special or unusual meaning within an area of technology. Then at [61] Moshinsky J quoted a passage from Flexible Steel Lacing Co v Beltreco Ltd stating that the construction of the specification is for the court, not for the expert.

The expert witnesses for TMA and Ubipark, Mr Sizer and Mr Elliot respectively, were assessed by the court to have most, if not all, of the qualities of the skilled addressee [66]. Further, both witnesses gave evidence in a clear and considered way and both were acting to assist the court – [50] and [53].

Yet his honour was prepared on several occasions to not accept the views of either witness on the understanding of various features of the claims of the patent and instead relied upon his own understanding of the recited features. In such instances, the court emphasised the ordinary meaning of the words used to define the integer in question-see for example [114] – [115] where the court interpreted integer 1.3.2 and 1.3.3 of claim 1 and [139] where the court interpreted integer 1.3.4.

Expert evidence, whether prepared for an opposition proceeding or a court matter, almost always sets out an interpretation of every word or phrase in a claim, whether the wording has a technical meaning or not. Further, experts in their evidence almost always go further and express conclusions on the issues of novelty and infringement for example, even though these are matters for the determination of the court and not the witness. The statements by Moshinsky J on the role of experts are not new but are a reminder of well-established principles. They can serve as an encouragement to present expert evidence that is more targeted and concise, focusing on the matters where experts can provide useful assistance to a hearing officer or Judge. No doubt more concise evidence would be welcome by parties and hearing officers and Judges.

Finally, it is also interesting to note that in this case, a failure in the views of UbiPark’s expert evidence on inventive step resulted in the court finding that the allegation of lack of inventive step was not made out. Mr Elliot was asked to address the hypothetical question that was answered by the invention, and he did this before reading the patent specification. Unfortunately for UbiPark, the solution that Mr Elliot arrived at omitted two features of claim 1. He had therefore failed to arrive at the solution that had been claimed. The court was therefore not satisfied that the invention as claimed was obvious [229-230].

Thus, it is still the case that if a party wishes to establish that a claimed invention is obvious, then very persuasive evidence is that provided by an expert witness who arrives at the claimed invention without first reading the specification.

[1] UbiPark Pty Ltd v TMA Capital Australia Pty Ltd (No 2) [2023] FCA 885


Chris has extensive experience in conducting litigation for local and international clients, and has conducted cases concerning the validity and enforcement of patents, trade marks and designs, as well as the obtainment of rights in appeals from the Australian Intellectual Property Office.