The board may consider an affidavit to be admissible evidence even if it is signed by the general manager of the appellant (see T 327/91). In T 2003/08 of 31 October 2012 date: 2012-10-31 (reported in this chapter) the board observed that relations with the appellant's (opponent's) company could possibly have influenced Dr W's and Dr K's objectivity concerning their declarations ("Eidesstattliche Versicherung"). The board considered that its reservations concerning declarations E1 (declaration of Dr W, lecturer) and E2 (declaration of Dr K, member of the audience) could possibly be dispelled by hearing the authors of declarations E1 and E2 themselves.

In T 523/14 the appellant (patent proprietor) objected to the credibility of statements written by two employees of the respondents concerning alleged prior publication D11 (an advertising newsletter sent by e-mail). In the board's view, while the written statements of independent persons would tend to carry more weight, the statements of employees of parties to the proceedings were not objectionable per se. In this case, the content of written statements was considered sufficiently credible because it was corroborated on its crucial points by other documents (a screenshot of Microsoft Outlook documenting the forwarding of the e-mail containing D11 as an attachment, and a magazine published comprising an article which reproduced statements of D11). In this respect, the present case was not comparable with T 1257/04, in which an employee statement was the sole piece of evidence filed to prove the public availability of a brochure.

In T 558/95 the board held that the fact that the statutory declarations produced by the opponent partly used the same wording and had been drawn up by employees of the opponent did not necessarily mean they should be excluded as inadmissible. The opposition division had discretion to decide whether to examine them, and to determine whether or not the evidence in them was sufficient.