4.1. Principle of free evaluation of evidence
Overview
T 2517/22 × View decision
Abstract
In T 2517/22, in support of their argument of lack of inventive step, appellant 2 (opponent) had submitted documents D2 (operating manual) and D2a, which was the affidavit of an employee of appellant 2, Mr R.
Already in the notice of opposition and again in their reply, after the patentee had put into question the probative value of the affidavit D2a, appellant 2 had offered Mr R as a witness. In the annex to the first summons, the opposition division considered D2a to be sufficient evidence for public availability of D2 and did not summon Mr R as witness. In the annex to the second summons, discussion of novelty over D2 was envisaged for the oral proceedings. The opposition division changed its mind however and announced, after discussion of public availability of D2 during the second oral proceedings, that D2 was not part of the prior art albeit without taking into account the previous offer to hear a witness on the topic.
In the board's view, the statements in the affidavit D2a represented facts which were a priori of high relevance for the establishment of whether or not D2 was part of the prior art in the sense of Art. 54(2) EPC, and therefore of high relevance for the outcome of the opposition proceedings. An offer to hear the undersigned of the affidavit D2a as a witness represented a further relevant and appropriate offer of evidence for the facts. The board stated it was a party's choice to present whatever means of evidence it considered to be suitable and it was an opposition division's duty to take its decision on the basis of all the relevant evidence actually available rather than to expect the presentation of more preferred pieces of documentary evidence, and to speculate on the reasons for and draw conclusions from their absence. The opposition division was of course free to evaluate any evidence provided by a party, but this freedom could not be used to disregard evidence that had been offered, and which might turn out to be decisive for a case, in particular not with the argument that some better evidence would have been expected.
Instead of accepting the evidence offered by appellant 2, the opposition division appeared to have based its decision on general assumptions made on the capability of persons to recollect events after a certain time period (15 years) and specific assumptions made on the witness's personal capability, knowledge and experience, thus implicitly on assumptions made on the veracity of his statements and on his credibility. By making these assumptions without hearing the offered witness person, the opposition division had in fact assessed evidence without examining it.
According to the respondent (patent proprietor), the offer of Mr R as a witness was not substantiated. For the board, affidavit D2a appeared to contain the factual information relevant for the outcome of the case. Before the oral proceedings, the opposition division had not shared the respondent's concerns about the veracity of D2a. The board stated that appellant 2 did not have to address these concerns and had no obligation to announce in their offer how exactly the witness would be able to corroborate his own statements, e.g. by answering in advance hypothetical questions that might possibly arise. Such questions would normally be asked during witness hearings in order to assess the credibility of the witness and the exactness of their memory, which is one of the main purposes of the hearing. A sufficiently exact recollection of various events 15 years later should not have been denied beforehand.
Appellant 2 requested that the decision be set aside due to a violation of their right to be heard and to remit the case. The board concluded that the failure to consider appellant's 2 offer to hear a witness on the public availability of D2 constituted a substantial procedural violation of the right to be heard. The decision of the opposition division to reject both oppositions was set aside in order to allow re-examination of the public availability of D2 taking into account all the evidence admissibly submitted by appellant 2.
4.1. Principle of free evaluation of evidence
This section has been updated to reflect case law and legislative changes up to 31 December 2023. For the previous version of this section please refer to the "Case Law of the Boards of Appeal", 10th edition (PDF). |
Neither in the EPC nor in the case law of the board of appeal are formal rules laid down for the evaluation of evidence (reaffirmed in G 2/21, OJ 2023, A85, point 47 of the Reasons, before analysis of the law of the contracting states under Art. 125 EPC). The Enlarged Board of Appeal has recalled many times that proceedings before the EPO are conducted in accordance with the principle of the free evaluation of evidence (G 1/12, OJ 2014, A114, citing G 3/97, OJ 1999, 245, point 5 of the Reasons; and G 4/97, OJ 1999, 270, point 5 of the Reasons), which it reaffirmed in the more recent G 2/21 (point 29 of the Reasons). The decision being largely devoted to this point, the principles set out and confirmed there are reported below in a separate subsection.
The EPO departments have the power to assess whether the alleged facts are sufficiently established on a case-by-case basis. Under the principle of free evaluation of evidence, the respective body takes its decision on the basis of all of the evidence available in the proceedings, and in the light of its conviction arrived at freely on the evaluation whether an alleged fact has occurred or not (see e.g. T 482/89, OJ 1992, 646; T 592/98, T 972/02; see also e.g. T 838/92, in which the board found there was a detailed and consistent body of evidence establishing that a device had been on sale before the patent application was filed). See also G 2/21, point 34 and T 1138/20 point 1.2.2 of the Reasons.
However, the principle of free evaluation of evidence in EPO proceedings cannot go so far as to justify the refusal of a relevant and appropriate offer of evidence. Free evaluation of evidence means that there are no firm rules according to which certain types of evidence are, or are not, convincing. The deciding body must take all the relevant evidence before deciding whether or not a fact can be regarded as proven (T 474/04, OJ 2006, 129, citing G 3/97, OJ 1999, 245, point 5 of the Reasons – see also G 2/21, point 34 and T 1138/20 point 1.2.2 of the Reasons, which talk of a "decision on the basis of all the relevant evidence available in the proceedings"). On the other hand, failure to submit evidence despite a board's request to do so may be viewed as a sign that the evidence would perhaps not confirm what has been claimed (see T 428/98, OJ 2001, 494).
Ruling on a refusal to hear witnesses, the board in T 1363/14 held that the principle of free evaluation of the evidence did not apply until after it had been taken and could not be used to justify not taking evidence offered. This was confirmed in G 2/21, point 44 of the Reasons, which also cites T 2238/15; see also in this chapter III.G.2.2.
In J 14/19 (stay of the proceedings) the board explained that the EPO did not have any discretion when deciding on a stay of proceedings under R. 14(1) EPC. If a third party demonstrated that the requirements in R. 14(1) EPC were met, the proceedings for grant had to be stayed. This was not the same as deciding whether the factual requirements for a stay under R. 14(1) EPC were indeed met, which was not a matter of discretion but a question of evaluating the evidence. The latter saw the decision-making body examine the evidence to decide whether it was satisfied that the claimed facts were correct (see G 1/12, OJ 2014, A114). If it considered that a pivotal fact had not been established, it could order that more evidence be submitted under Art. 114(1) EPC.