“…However, the truth degree alone is too weak a criterion for the goodness of a linguistic summary, and some other quality (validity) criteria have been proposed exemplified by, e.g., Yager's [33] measure of informativeness, and then five additional measures proposed by Kacprzyk and Yager [17] and Kacprzyk, Yager and Zadrożny [18]: truth, degrees of imprecision, covering and appropriateness, and a length of a summary. For even more measures, see Kacprzyk, Wilbik and Zadrożny [15], [16]. Unfortunately, though all those measures can better capture than the truth degree alone how good a linguistic summary is, the comprehensiveness of some of them to an average user may be questionable.…”