The Guidelines (C‑V, 15.2 – November 2018 version) state that reference can be made to more than one communication only in exceptional cases and that, especially if the various communications deal with different sets of claims and it is therefore unclear which of the reasons given in them by the examining division might be essential to its decision to refuse, a fully reasoned decision should be issued instead.

In T 897/03 the board held that a decision that leaves it to the appeal board and the appellant to speculate as to which of the reasons given by the examining division in different communications might have been decisive for the refusal of the application, could not be considered to meet the requirements of R. 68(2) EPC 1973 (see also T 177/15, T 652/97 and T 278/00, OJ 2003, 546).

In T 180/10 two communications had been referred to. However, contrary to what was stated in the second communication ("the applicant's explanations … have been carefully considered"), it was apparent that the examining division had ignored all the appellant's arguments since this communication and, therefore, the decision were silent on them. The requirements of R. 68(2) EPC 1973 were not fulfilled.

In T 737/11 the board concluded that considerable uncertainty existed as to the precise reasons on which the contested decision was based. The claims were amended substantially between the two communications to which the written reasoning of the contested decision referred. Furthermore, oral proceedings had taken place in absence of the applicant, despite the applicant withdrawing the respective request and the minutes of these oral proceedings were not mentioned in the decision. This was held to amount to a substantial procedural violation and insufficient reasoning. In both T 406/15 and T 62/13 the examining division had refused an application based on the file as it stood, using a form referring to two earlier "communications". However, the file in each case revealed that these had not been "communications" as such. The examining division had issued only one formal communication that raised just one briefly reasoned objection to lack of novelty and did not clearly explain why the application had been refused. The board nevertheless held that it was just enough to fulfil the obligation to substantiate decisions, but only having taken into account that the appellants themselves had not argued on appeal that the reasoning was insufficient.

In T 1946/17 the board held that a blanket statement like "arguments were carefully considered" but "no new evidence" was provided, in the communications to which the decision refers cannot be considered to address the arguments raised and thus constitutes insufficient reasoning.