11 April 2023

G 2/21 Evidence and Inventive Step

The Enlarged Board of Appeal (EBA) of the European Patent Office has issued its decision in G 2/21 relating to the requirements for post-published evidence to be taken into account when assessing inventive step.


Three questions were referred to the EBA following an opposition before one of the Technical Boards of Appeal in which the patentee sought to rely on data which was not in the application as filed (post-published evidence) as evidence of a technical effect in support of inventiveness of the claims.

The first of these questions asks whether post-published evidence must be disregarded if proof of a technical effect rests exclusively on the post-published evidence.

The second and third questions relate to the concept of plausibility. According to a long line of European case law, a technical effect must be plausible to the skilled person based on the disclosure of the application as filed or the skilled person’s common general knowledge for it to be taken into account in assessment of inventive step. Post-published evidence can only be taken into account if this plausibility threshold has been reached.

However, the referral identifies two lines of case law: one in which an ab initio plausibility standard is applied in which the skilled person would have considered the effect plausible, and one in which an ab initio implausibility standard is applied in which the skilled person would have seen no reason to consider the effect implausible.  The second and third questions asks which of these standards is applicable.

The ab initio implausibility standard is lower than the ab initio plausibility standard and so a decision identifying one of these plausibility standards as the correct one would have significant ramifications as to the data which needs to be present in a patent application at the time of filing in order for the claims of the patent application to be inventive.

The decision

The first question was answered in the negative; post-published evidence may not be disregarded for the sole reason that the post-published evidence had not been public before the filing date of the patent application and was not present in the application as filed.

Although the second and third questions referred to the EBA were framed based on the answer to the first question being yes, the EBA did address the concept of plausibility.

The EBA did not, however, choose between the ab initio implausibility standard and the ab initio plausibility standard; rather, the EBA pointed out that the concept of plausibility is not a distinct condition of patentability. Consequently, the following guidance provided by the EBA makes no mention of plausibility:

A patent applicant or proprietor may rely upon a technical effect for inventive step if the skilled person, having the 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.”

Applying this to cases from the ab initio plausibility and ab initio implausibility lines of case law, the EBA concluded:

[T]he Enlarged Board is satisfied that the outcome in each particular case would not have been different from the actual finding of the respective board of appeal. Irrespective of the use of the terminological notion of plausibility, the cited decisions appear to show that the particular board of appeal focussed on the question whether or not the technical effect relied upon by the patent applicant or proprietor was derivable for the person skilled in the art from the technical teaching of the application documents.


Guidance as to whether a technical effect can be taken into account when assessing inventive step has been provided in the form of the above “derivable” test. It now falls to the referring Technical Board of Appeal to interpret and apply this test to the case in question.