An online system receives information describing a target group of online system users from a third party system and determines whether to store the information describing the target group. Online system users included in the target group are identified and scores are determined for each of the identified user. A score associated with a user represents the online system's effectiveness in targeting content to the user via targeting criteria maintained by the online system. Based on the scores, the online system determines a group score associated with the target group and stores the information describing the target group if the group score satisfies one or more criteria. If the information describing the target group is stored, the online system may determine whether to continue storing the information describing the target group based on revenue obtained by the online system from presenting content based on the target group.