3.4.3 The requirement of sufficient reasoning

According to the case law of the boards of appeal (see e.g. T 951/92; T 740/93; T 278/00, OJ 2003, 546; T 963/02; T 897/03; T 316/05; T 1182/05; T 1366/05; T 1709/06; T 2352/13; T 1655/21; T 1901/22) a "reasoned" decision should deal with all important issues of dispute. The grounds upon which the decision was based and all decisive considerations in respect of the factual and legal aspects of the case must be discussed in detail in the decision.

A decision should discuss the facts, evidence and arguments which are essential to the decision in detail. It also has to contain the logical chain of reasoning which led to the relevant conclusion (see T 292/90, T 278/00, T 316/05, T 1366/05, T 1612/07, T 1870/07, T 2366/11, T 66/20, T 1713/20, T 1532/21, T 1564/21).

The requirement in R. 111(2) EPC of a decision being reasoned is not met if the decision merely contains statements that at best give rise to speculation about what the deciding body might have intended to express (T 278/00, T 1713/20, T 1532/21, T 1564/21). This requirement cannot be construed in such a way that in spite of the presence of unintelligible and therefore deficient reasoning, it is up to the board or the appellant to speculate as to what might be the intended meaning of it. Deficient reasoning cannot be compensated for by the speculative interpretation of the appellant or guess work by the board (T 278/00).

If a decision is merely reasoned by a reference to a preceding communication, the criteria of R. 111(2) EPC are only met if said communication itself fulfils these criteria (T 963/02, T 897/03, T 1612/07, T 2366/11). The decision under appeal must not leave it to the board and the appellant to speculate as to which of the reasons given in preceding communications might be essential to the decision to refuse the application (T 963/02, T 897/03, T 2366/11). See also in this chapter III.K.3.5.

The absence of reasoning satisfying the criteria of R. 111(2) EPC amounts to a substantial procedural violation requiring the decision under appeal to be set aside (T 292/90, T 963/02, T 897/03, T 1366/05, T 1612/07, T 2366/11).

In T 70/02 the board held that reasoning does not mean that all the arguments submitted should be dealt with in detail, but it is a general principle of good faith and fair proceedings that reasoned decisions contain, in addition to the logical chain of facts and reasons on which every decision is based, at least some motivation on crucial points of dispute in this line of argumentation in so far as this is not already apparent from other reasons given.

In T 2241/19 of 10 July 2024 date: 2024-07-10 the board emphasised that the final decision must address all those objections which could potentially have led to a different outcome in order to comply with the requirement of R. 111(2) EPC.

In T 1123/04 the board was of the view that it was not enough if a board of appeal had to reconstruct or even speculate as to the possible reasons for a negative decision in the first-instance proceedings. As a rule, a decision within the meaning of R. 68(2) EPC 1973 should be complete and self-contained. The reasons were inadequate if the only arguments advanced by the examining division were unsubstantiated claims.

In T 1622/21 the board found that neither were "all decisive considerations in respect of the factual and legal aspects of the case discussed in detail in the decision", nor did the appealed decision "contain the logical chain of reasoning which led" to the finding of the subject-matter of claim 1 lacking an inventive step. Insufficient reasoning in the appealed decision prevented the board from following the line of argument having led to the examining division's finding of lack of inventive step.

In T 596/22 the board noted that it was not a requirement for a reasoned decision to give reasons as to why an opposition division deviated from its preliminary opinion.