For a long time, board of appeal practice was governed by the landmark decision T 156/84 (OJ 1988, 372), according to which the principle of ex officio examination by the EPO under Art. 114(1) EPC took precedence over the possibility under Art. 114(2) EPC of disregarding facts or evidence not submitted in due time. Accordingly, the main criterion for deciding on the admissibility of late-filed documents and evidence was their relevance, i.e. their evidential weight in relation to other documents already in the case (see e.g. T 322/95, T 475/96, T 864/97, T 892/98, T 605/99). If the board conducted an "examination as to relevance" when exercising its discretion under Art. 114(2) EPC 1973, then the admission of a citation which could have been submitted earlier and was therefore late filed depended on whether it was decisive (relevant) for the outcome of the case (see T 258/84, OJ 1987, 119). If it was relevant - i.e. if it might cause the patent to be revoked or its scope to be limited - it had to be admitted into the case and taken into account (T 164/89, T 1016/93).
Regarding examination as to relevance, the board explained in T 560/89 (OJ 1992, 725) that Art. 114(2) EPC 1973 allowed the EPO to disregard documents which contained no more information than the documents filed on time and did not disclose matter which could change the outcome of the decision. According to the decision in T 611/90 (OJ 1993, 50), late-filed evidence, documents and other matter could be rejected by the boards of appeal on the ground of their irrelevance, i.e. on the basis that they were no more "weighty" or "cogent" than documents which were already in the case (T 237/03). Late-filed evidence is only admissible under the established case law of the boards of appeal if it is more relevant than the evidence already on file (T 1557/05).
If, having regard to the facts of the case as a whole, the new submission had no material bearing on the decision, the board could, according to Art. 114(2) EPC 1973, disregard the submission without having to give detailed reasons (see T 156/84, OJ 1988, 372, T 71/86, T 11/88, T 705/90).
In T 326/87 (OJ 1992, 522) the board took the same line, on the grounds that Art. 114(2) EPC 1973 set a legal limit on the inquisitorial duties of the appeal boards and that these duties should not be interpreted as extending to carrying out a roving enquiry into facts alleged and evidence adduced at a late stage of the proceedings. The main criterion for deciding on the admissibility of a late-filed document was its relevance (see also T 286/94).
According to T 97/90 (OJ 1993, 719) the wording of Art. 114(1) EPC 1973 did not mean that the boards of appeal had to conduct rehearings of the first-instance proceedings, with unfettered right, and indeed obligation, to look at all fresh matter regardless of how late it was submitted. Art. 114(2) and Art. 111(1) EPC 1973 set a clear limit to the scope of any new matter that could be introduced into an appeal by the parties so that cases on appeal had to be, and remain, identical or closely similar to those on which decisions at first instance had been rendered. This case law was confirmed by the boards of appeal inter alia in T 26/88 (OJ 1991, 30; where it was stated that the essential function of the appeal procedure was to determine whether the decision issued by a department of first instance was correct on its merits), T 326/87 (OJ 1992, 522), T 229/90, T 611/90 (OJ 1993, 50) and T 339/06.