Armchair inventions part 2:  Preliminary opinion on plausibility at the EPO (G2/21)


The issue of plausibility was previously referred to the Enlarged Board of Appeal (EBA), the highest judicial authority at the European Patent Office (EPO). Our article on the referral can be found here. The oral proceedings in G2/21 took place in Munich on 24 November 2022. In preparation for the oral proceedings, the EBA published their non-binding preliminary opinion, which can be found here.

Opinion on the referred question 1

In the preliminary opinion, the EBA considered that the principle of free evaluation of evidence applied at the proceedings before the EPO “does not appear to allow to disregard” post-published evidence for the sole reason of such evidence being decisive for the final decision on the alleged technical effect at hand. The EBA stated:

“Disregarding such evidence as a matter of principle would deprive the party submitting and relying on such evidence of a basic procedural right generally recognised in the contracting states and enshrined in Articles 113(1) and 117(1) EPC.”

It follows that the EBA likely considers that post-published evidence should not be disregarded per se. This preliminary opinion is in line with the current practice of the EPO to assess post-published data when deciding on the technical effect of the invention.

Opinion on the referred questions 2 and 3

The EBA then looked into whether such post-published evidence should be accepted when the skilled person at the filing (or priority) date would have deemed the effect presented “plausible” (ab initio plausibility, higher bar) or whether the post-published evidence should be disregarded if the skilled person would have considered the effect “implausible” (ab initio implausibility, lower bar).

The EBA stated that from the case law and submissions received during G2/21 referral they understand that the core issue is what a skilled person at the filing date would see as the technical teaching of the claimed invention. They highlighted that any alleged technical effect which is relied upon to show the inventiveness of the invention, needs to “be encompassed by that technical teaching and to embody the same invention”.

With that hurdle satisfied, the EBA stated it would remain to be determined whether the skilled person would have any significant reason to doubt the technical effect for which the post-published evidence is submitted. If not, then such post-published evidence could inform the decision of a deciding body on the inventiveness of the claimed subject-matter. It would therefore appear that the EBA may be favouring the lower bar of ab initio “implausibility”, as long as the submitted post-published data relates to a technical effect within the scope of the technical teaching of the originally filed application and embodying the same invention.


The preliminary opinion presented above is not binding, and we will have to wait until the final decision to discover the future for plausibility at the EPO. The EBA acknowledged the importance of the referral during the oral proceedings in November and we expect to receive the written decision in the first half of 2023.