An International Guide to
Patent Case Management for Judges

2.4.2 Role of experts – Federal Court of Australia (invalidity proceedings)

Expert evidence in patent litigation in the Federal Court of Australia is almost exclusively given on affidavit and by way of joint report. Expert evidence is expected to comply with the requirements set out in the applicable practice note (at the time of writing, the Expert Evidence Practice Note (GPN-EXPT), dated October 25, 2016) as well as the relevant rules of court.⁴⁵ These requirements place particular focus on the importance of the expert’s independence as well as matters going to admissibility and the manner in which experts’ evidence will be prepared and presented at trial. The practice note specifically requires every expert witness to read the Harmonised Expert Witness Code of Conduct⁴⁶ and agree to be bound by it. Unlike in the Patent Office, the rules of evidence apply in Federal Court proceedings.

Where an allegation of invalidity is raised in answer to an application for preliminary injunctive relief, expert evidence bearing on questions of construction of the specification or the contents of prior art documents will usually be given on affidavit. Cross-examination is rare in interlocutory applications of this kind.

In the case of invalidity evidence to be received at trial, the following procedural matters should be noted:

• First, the practice note requires litigants intending to rely on expert evidence to consider and inform the court at the earliest opportunity of a range of matters, including the number and identity of proposed experts and the issues that each is expected to address.
• Second, although the practice note and rules of court make provision for the engagement of common or joint experts and court-appointed experts, such witnesses have rarely been utilized to date.
• Third, the court will often require experts with the same or overlapping expertise (or experts giving evidence on particular issues) to participate in a conference or conclave of experts and in the preparation of a joint report prior to the trial. Although the parties’ lawyers will usually be involved in formulating the list of issues for the conference or conclave, the ordinary course is for the conclave to proceed and for the report to be drafted without any involvement from the parties or their lawyers. In some cases, this will result in a series of joint reports being prepared by different pairs or groups of experts. In others (particularly where the fields of expertise overlap), there may be a larger report with input from a larger number of witnesses. It is not uncommon to see joint reports with four or five participants (or more) contributing.
• Fourth, particularly in cases where the joint report process is being used, the court will commonly direct that the experts give some or all of their evidence concurrently at trial rather than through traditional processes of experts being called and cross-examined serially. This process, colloquially known as a “hot tub,” may take a number of forms but will commonly be structured by reference to topics or issues dealt with in the joint report. For each topic or issue, there may be an opportunity for the experts to give “opening statements” or to answer questions from the presiding judge. One party’s legal representative will often begin questioning by asking a question of an expert called by the opposing party. Each expert will have an opportunity to comment on any answers given by other experts orally or in written evidence. Once the parties’ legal representatives have exhausted their questions for the concurrent session on a topic, there may be an opportunity for “traditional” individual cross-examination of experts on matters arising from their oral or written evidence.⁴⁷

Expert evidence relating to invalidity will generally pertain to the same issues discussed at Section 2.2.2.3 in relation to Patent Office proceedings (in particular, evidence assisting the court in understanding the patent specification, the prior art, the state of knowledge – including CGK – in the relevant field at the priority date). In cases relating to older patents, there may be expert evidence establishing that a particular document would have been ascertained and regarded as relevant to a particular technical problem by the skilled addressee.