"Grounds or evidence" under Art. 113(1) EPC are to be understood as meaning the essential legal and factual reasoning on which the decision is based (T 532/91, T 105/93, T 187/95, T 1154/04, T 435/07, T 1898/11). In T 951/92 (OJ 1996, 53) the board ruled that the term "grounds or evidence" should not be narrowly interpreted and was to be understood as referring to the legal and factual reasons leading to refusal of the application, and not in the narrow sense of a requirement of the EPC.
In T 375/00 the appellant (opponent) considered that the technical problem mentioned by the opposition division in its decision was different from that discussed in the preceding proceedings. The board held that the appellant's right to be heard had not been violated, because the definition of the objective problem was part of the arguments, not part of the grounds as specified in Art. 113(1) EPC 1973.
In T 33/93 the board stated that the citation of a board of appeal decision for the first time in the decision under appeal was not a fresh ground or piece of evidence within the meaning of Art. 113(1) EPC 1973, but a mere repetition of arguments, since it only confirmed the position duly brought to the appellant's attention.
In T 1634/10 the examining division had issued a reasoned communication setting out its objections in the light of two prior art documents, to which the appellant responded with a new claim and new arguments as to why the examining division had been wrong in its interpretation of the documents. Refusing the application, the examining division held that the amendments submitted by the appellant were not substantial. The board decided that the examining division had introduced neither new grounds of refusal nor new evidence. The mere fact that the examining division had not agreed with the submission of the appellant did not amount to a breach of the right to be heard.