4.5.3 Prima facie relevance
According to established case law of the boards of appeal, a decisive criterion for admitting late-filed documents is their prima facie relevance, see e.g. T 1002/92, OJ 1995, 605; T 212/91, T 931/06, T 1883/12, T 1511/14 and T 838/17; for appeal proceedings, see in particular chapters V.A.4.1.2, V.A.4.4.6, and V.A.4.5.5.
Prima facie relevance is ascertained on the face of the facts, i.e. with little investigative effort, which reflects the need for procedural expediency in considering and admitting late-filed facts and evidence (T 1883/12).
In T 1348/16 the board considered that the opposition division, in admitting a document which it had found to be prima facie relevant and potentially prejudicial to the maintenance of the patent in suit, had based its decision on the right principles and that there was no reason to doubt that it had exercised its discretion in a reasonable way. This was not contradicted by the fact that a detailed analysis of the document later led the opposition division to conclude that it was actually not novelty destroying and that another document represented the most relevant state of the art. Such an in-depth analysis was not part of the prima facie assessment of the relevance of a document. See also T 1614/18.
In T 1525/17 the board observed that it was inherently contradictory to take late-filed documents as a basis for an in-depth examination of the patentability requirements, and so consider them as to their substance, yet at the same time declare them not admitted, as the opposition division had done in this case, having fully considered documents E5 and E6 in its thorough substantive assessment of inventive step. That assessment had not been referred to explicitly as a prima facie assessment of the documents' relevance; nor could it be regarded implicitly as a matter to be settled before dealing with their non-admission. The refusal to admit them therefore amounted to an erroneous exercise of discretion. See also T 1185/15 (necessary thorough analysis at odds with finding that document is not prima facie relevant) and T 346/16. See likewise T 847/20 in which the opposition division had not carried out a prima facie assessment but had fully considered the requests before concluding that they could not be admitted. The board took the view that the opposition division had wrongly exercised its discretion because, having implicitly admitted the requests, there was no discretion left not to admit them. T 2324/14 and T 2026/15 address implicitly admitted requests in examination proceedings, see chapter IV.B.2.4.1.
In T 838/17 the board held that an assessment of whether a prior art document prejudiced inventive step, even at prima facie level, needed, necessarily, to go beyond an assessment of whether that document prejudiced novelty. An assessment of inventive step did not stop at the identification of a difference. While a lack of difference was sufficient to substantiate an inventive-step objection, the identification of a distinguishing feature was not sufficient to demonstrate that the invention would not have been obvious. Even if the opponent's argumentation did not go beyond the statement that there was actually no difference, proper exercise of discretion would require, at least, some explanation as to why the opposition division saw no reason to suspect that the difference would have been obvious.
In T 1614/18 the board stated, with reference to the version of Guidelines applicable at the relevant time, that the competent department had to take a late-filed and "prima facie" relevant evidence into consideration no matter what stage the procedure had reached and whatever the reasons for the belated submission. The fact that after discussion at the oral proceedings the suspected relevance was not confirmed did not imply that the discretion was applied incorrectly. In the case in hand procedural expediency was not an issue since D6 was filed two months before the oral proceedings, and therefore no undue burden affecting negatively the position of the appellant could be reasonably invoked.
In T 2716/19 the board decided the opposition division had applied the criterion of prima facie relevance in an unreasonable way because it had limited its assessment to the subject-matter of the then main request. It should have extended to the subject-matter of the auxiliary requests on file.
In T 21/22 the opposition division had conducted a comprehensive examination of late-filed D20 in respect of novelty and inventive step prior to concluding that it should not be admitted on the basis of its late filing and the fact that it was not prima facie relevant. The opposition division had therefore not only carried out a mere prima facie assessment but had fully considered D20 and the objections based upon it. Thus, the board held that there was no discretion left for the opposition division not to admit D20 into the proceedings, since it was de facto fully considered (and therefore implicitly admitted) by the opposition division.