2.3. Freedom of choice when selecting evidence

Under Art. 117(1) EPC, parties are free to choose what kind of evidence they present. In particular, they can make use of any of the means of evidence listed in that article (T 142/97, OJ 2000, 358). In T 1710/12, in the board's view, Art. 117(1) EPC gives no order of preference regarding the means of giving or obtaining evidence in proceedings before the EPO and it remains the free choice of a party to rely on the hearing of a witness (Art. 117(1)(d) EPC or on production of a sworn statement in writing (Art. 117(1)(g) EPC). For other findings that witness testimony does not necessarily carry less weight than documentary evidence, see also T 918/11, T 2565/11 and T 441/04 (in which, however, the board first observed that documentary evidence was generally preferable to witness testimony for proving long-ago events).

In T 329/02, the board found that it was not in keeping with good procedural practice for an opposition division not to take up an opportunity to hear a witness in evidence on a disputed matter that was highly relevant to the legal validity of the contested patent, and instead to require written declarations in place of the oral evidence.

See also chapter III.G.3.3 "Right to be heard" below.