The centroid or consensus of a set of objects with qualitative attributes

► We study assertions about objects containing qualitative values. ► These values can be represented by a hierarchy (a tree) containing them. ► The defined function conf (r,s) measures similarity of qualitative values r and s. ► Using conf, we find the centroid or consensus (an object) of a set of assertions. ► The “variance” or “disagreement” about this consensus object is also measured.