Plausibility – G 2/21: Decision issued by Enlarged Board of Appeal

The EPO’s Enlarged Board of Appeal (EBA) has recently announced the eagerly awaited decision in respect of the G 2/21 (“Plausibility”) referral made in 2021. The decision can be found here and our original article reporting the referral can be found here.

The referral included three questions relating to the use of post-published evidence to support a technical effect, and what plausibility standard is required if post-published evidence is relied upon. Specifically, if the acknowledgement of an inventive step relies on post-published evidence:

     1) Should an exception to the principle of free evaluation of evidence (see e.g. G 3/97, Reasons 5, and G 1/12, Reasons 31) be made in that post-published evidence must be disregarded if proof of the technical effect is exclusively provided by the post-published evidence?

     2) If the answer to (1) is yes, can the post-published evidence be taken into consideration if the skilled person would have considered the technical effect plausible at the filing date (ab initio plausibility)?; or

     3) If the answer to (1) is yes, can the post-published evidence be taken into consideration if the skilled person would have seen no reason to consider the technical effect implausible at the filing date (ab initio implausibility)?

As regards the first question, in line with the principle of free evaluation of evidence, the EBA held that evidence cannot be disregarded solely because it is post-published. In this regard, the EBA decision states that:

“Evidence submitted by a patent applicant or proprietor to prove a technical effect relied upon for acknowledgement of inventive step of the claimed subject-matter may not be disregarded solely on the ground that such evidence, on which the effect rests, had not been public before the filing date of the patent in suit and was filed after that date.”

Although the first question was effectively answered with “no”, the EBA did not find that this rendered questions 2 and 3 to be irrelevant and provided some important guidance in relation to plausibility.

However, the EBA avoided the debate relating to “ab initio plausibility” and “ab initio implausibility” and rather pointed out that “plausibility” does not amount to a distinctive legal concept or a specific patent law requirement under the EPC, but rather a “generic catchword” used as a criterion for the reliance on a technical effect.

In this regard, the EBA noted that when assessing if a technical effect may be relied upon in support of inventive step, the relevant standard concerns the question of whether the skilled person with their common general knowledge in mind, and based on the application as originally filed, would derive said effect as being encompassed by the technical teaching and embodied by the same originally disclosed invention.

The EBA acknowledged the “abstractness” of these criteria but concluded that it has provided “guiding principles” to allow the deciding body to take a decision as to whether or not post-published evidence may or may not be relied upon.

It will be interesting to see how the referring Technical Board of Appeal applies the EBA’s criteria to the case in question.