More precisely, for each hierarchy concept for which attributes must be extracted, the instances associated to all class labels linked under the subhierarchy rooted at the concept are collected as a union set of instances, thus exploiting the transitivity of IsA relations.
evaluation results indicate that the accuracy of the extracted lists of attributes is higher by 8% at rank 10, 13% at rank 30 and 18% at rank 50, when using the automatically-extracted classes of instances rather than the comparatively more numerous and a-priori more reliable, humangenerated, collaboratively-vetted classes of instances available within Wikipedia (Remy, 2002).