Preparing evidence

During opposition proceedings, both parties provide evidence to the Patent Office to support their respective positions and to ultimately assist the Patent Office in determining the opposition. We focus on working with the best experts to strategically prepare evidence that supports our client’s position.

The role of evidence

The primary purpose of evidence is to provide the Patent Office with the facts, and in many cases, expert opinion based on those facts. Example evidence includes evidence on what was published or used in public before the priority date of the relevant patent application or innovation patent, the state of common general knowledge at the priority date, the interpretation of technical terms in the opposed patent specification or the prior art, and what (if any) difficulties would be faced by a person skilled in the art when attempting to practice the invention after reading the specification.

The role of evidence is not to provide arguments as to how facts or opinions satisfy, or do not satisfy, the grounds of opposition. In fact, given the strict approach to extensions of time for preparing evidence, it may be a mistake to ask an independent expert to prepare such arguments. As stated by the Patent Office when criticising the preparation of arguments during the period prescribed for preparing evidence and drawing a distinction between submissions and evidence: ‘To the extent that the evidence contains submissions that could be made at hearing, it is not evidence. It is unnecessary (and inappropriate) to include argument in the guise of evidence.'1

What evidence to prepare and file

Identifying what evidence is required is arguably the most important aspect of an opposition. It requires a detailed consideration of the end objective. For example, an opponent’s interests may be best advanced by filing evidence in relation to only a subset of the claims of an application, to reduce cost, assist with meeting evidence preparation deadlines and to provide an implicit invitation to the applicant to amend in a particular manner.

The Commissioner of Patents constitutes a tribunal and not a court, and it is for this reason that the rules of evidence that apply to court proceedings do not apply. Despite the rules of evidence not applying, the Commissioner will still evaluate and weigh the evidence. The rules of evidence may generally be viewed as a useful best practice guide. For example, the Commissioner may be less likely to be satisfied that facts asserted by a party existed, if direct evidence was available to a party, but only hearsay evidence was filed.

While the Commissioner may in exceptional circumstances require or allow oral evidence, evidence is normally received as written declarations and the declarant (eg, the expert) is not required to attend to the final hearing for cross examination.

When to file evidence

Evidence is prepared in stages and must be filed at the Patent Office within certain time periods. More information on the stages and time periods of evidence may be found here.

Can you extend the time limits for filing evidence?

The Commissioner will extend an evidentiary period only if satisfied that:

  • the party who intended to file evidence within a relevant evidentiary period has made all reasonable efforts to comply with all relevant filing requirements, and despite acting promptly and diligently at all times to ensure the appropriate evidence is filed within the period, is unable to do so; or
  •  there are exceptional circumstances that warrant the extension.


As noted above, the Patent Office will be unsympathetic to extensions of time if the party has dedicated resources to preparing arguments, rather than evidence of facts and expert opinions. The Patent Office will also be unsympathetic to a party who seeks to use an expert knowing that the expert will be taking extended periods of leave during the period for preparing evidence.

Julie-Anne McCarthy and Bradley McCarthy v TRED Design Pty Ltd [2013] APO 57 (11 November 2013).