This revised version of the Guidelines for Examination will apply as from 1 November 2015. Until then, the September 2014 edition of the Guidelines remains valid.

8.1 Error margins in numerical values

The skilled person knows that numerical values relating to measurements are subject to measurement errors which place limits on their accuracy. For this reason, the general convention in the scientific and technical literature is applied: the last decimal place of a numerical value indicates its degree of accuracy. Where no other error margins are given, the maximum margin should be ascertained by applying the rounding-off convention to the last decimal place (see T 175/97), e.g. for a measurement of 3.5 cm, the error margin is 3.45-3.54. When interpreting ranges of values in patent specifications, the skilled person proceeds on the same basis.

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