Techniques are described for generating a hierarchical group based on a set of data. In one example, a method includes classifying two or more data items from a set of data with respect to a library of ontological concepts. The method further includes classifying the two or more data items with respect to lexical correlations between the two or more data items. The method further includes generating a hierarchical group in which the two or more data items are partitioned into one or more hierarchical partitions based at least in part on the classifying with respect to the library of ontological concepts and the classifying with respect to the lexical correlations, wherein each of the one or more hierarchical partitions comprises the two or more data items.