In decision T 666/89 (OJ 1993, 495) the board gave a ruling on novelty assessment in cases of overlapping numerical ranges. The patent related in particular to a shampoo comprising 8-25% anionic surfactant and 0.001-0.1% cationic polymer. In an earlier patent application a shampoo composition had been disclosed containing 5-25% anionic surfactant and 0.1-5.0% cationic polymer. The board held that the composition was not new. In the board's view, there was no fundamental difference between examining novelty in situations of so-called "overlap" or "selection", and in doing so in other situations, although it might be helpful, in order to verify a preliminary conclusion of a novelty examination in cases of overlap, to investigate whether or not a particular technical effect was associated with the narrow range in question. It needed to be stressed, however, that such a particular effect was neither a prerequisite for novelty nor could it as such confer novelty; its existence could merely serve to confirm a finding of novelty already achieved. The term "available" in Art. 54(2) EPC 1973 clearly went beyond literal or diagrammatical description, and implied the communication, express or implicit, of technical information by other means as well. Thus it was clear that matter that was hidden, not in the sense of being deliberately concealed but rather in the sense of being reconditely submerged in a document, would not have been "made available" in the above sense. In the case of overlapping ranges of physical parameters between a claim and a prior art disclosure, what would often help to determine what was "hidden" as opposed to what had been made available was whether or not a skilled person would find it difficult to carry out the prior art teaching in the range of overlap. Provided the information in the prior art document, in combination with the skilled person's common general knowledge, was sufficient to enable him to practise the technical teaching, and if it could reasonably be assumed that he would do so, then the claim in question would lack novelty. Novelty was carefully analysed on the basis of comparable considerations in T 366/90 and T 565/90.

Decision T 26/85 (OJ 1990, 22) suggested, as a specific test for determining whether a technical teaching had been made available to the public, posing the question whether the person skilled in the art would in the light of the technical facts seriously contemplate applying the technical teaching of the prior art document in the range of overlap. If it could be fairly assumed that he would do so, it had to be concluded that no novelty existed. This formulation of the question was adopted inter alia in T 279/89, T 666/89 (OJ 1993, 495), T 255/91 (OJ 1993, 318), T 369/91 of 7 October 1992 date: 1992-10-07, T 631/92 and T 660/93.

In T 751/94 the board regarded it as clear that the method according to the cited document was not to be carried out in the overlapping range, and consequently the overlap did not deprive the claimed invention of novelty. In addition, the combination of parameters in the claimed invention was not disclosed in, and was not clearly derivable from, the cited document.

In T 240/95 the appellant had argued that 0.5 to 60 minutes would not include 60 minutes as such inclusion would have to be worded "0.5 up to and including 60 minutes." The board held that, in accordance with established case law, disclosure of a range was considered to be an explicit disclosure of the end values.

In T 594/01 the board stated that it was common general knowledge that every experimental measurement in quantitative analytical chemistry as well as any result of any physical measurement could not be dissociated from the margin of uncertainty attached to the measurement. Normally, the uncertainty of a measured experimental value was irrelevant for the assessment of novelty. However, when a specific experimental value was disclosed in an example of prior art, seeking to distinguish the claimed subject-matter therefrom only in terms of an upper limit to be required to be "lower than" the experimental value must fail, as the claimed subject matter is still not distinguishable from the prior art within the margin of experimental error (see also T 708/05).

In T 1115/09 D1 disclosed that the gas at the outlet of the catalytic bed contained no more than about 10 ppm oxygen, i.e. a range of oxygen concentrations ending with the upper value of "about 10 ppm". According to the boards' established case law (see T 240/95), the disclosure of a range was an explicit disclosure of the end values. In the case at issue, it followed by analogy that the end value "about 10 ppm" was explicitly disclosed in D1. The question to be answered was whether this end value fell within the range defined in claim 1 at issue, i.e. "more than 10 ppm oxygen and up to 250 ppm". In the board's view, in the absence of a clear definition in document D1 of the relative term "about", the expression "about 10 ppm of oxygen" was to be given its broadest meaning, namely "10 ± epsilon ppm of oxygen". As the value "10+epsilon" was synonymous with the value "more than 10", the choice of the latter as the lower end of the range defined in claim 1 thus boiled down to the selection of one discrete value within the list of three disclosed in D1: "10‑epsilon", "10" and "10+epsilon". The board referred to T 730/01, according to which the selection of one item within one single list of equivalent alternative items did not confer novelty, concluded that the disclosure of document D1 inevitably led to subject-matter falling within the scope of protection of claim 1.

In T 1571/15 the overlap between the composition as claimed and the broad composition of D1 was narrow. D1 disclosed a preferred composition range and there was no pointer to work outside this range. The board stated that while it was true that the person skilled in the art might seriously contemplate working in the centre region of a prior art range when no other pointer (for instance in the form of examples of preferred ranges) to another region was present, this was no longer true if, as in the present case, such a pointer was present and was directed to another region.