ISO 9186-1:2014 specifies a method for testing the comprehensibility of graphical symbols. It provides a measure of the extent to which a variant of a graphical symbol communicates its intended message. The purpose is to ensure that graphical symbols and signs using graphical symbols are readily understood. The intention is to encourage the development of graphical symbols which are correctly understood by users when no supplementary (i.e. explanatory) text is presented. When such a graphical symbol cannot be developed, it might be necessary to present a graphical symbol together with supplementary text explaining its meaning in the language of the intended users.