Efficient evaluation of sets of resources is disclosed, including: determining a first plurality of representations from identifying information associated with a first set of resources; updating a first data structure corresponding to the first set of resources using portions of respective ones of the first plurality of representations; determining a second plurality of representations from identifying information associated with a second set of resources; updating a second data structure corresponding to the second set of resources using portions of respective ones of the second plurality of representations; and using the first data structure and the second data structure to compute a derived value associated with the first set of resources and the second set of resources.