Identifying actions for different groups of users after presentation of a content item to the groups of users

A computer program product comprising a computer readable storage medium having instructions encoded thereon that, when executed by a processor, cause the processor to:

• receive, at an online system, information identifying actions by users taken based on content presented to the users;
• generate, at the online system, a plurality of models from the identified actions by users with content presented to the user, each model corresponding to an action with content and determining likelihoods of users of the online system performing the action when presented with content based on characteristics of the users and characteristics of the content;
• receive a content item and information identifying sets of users eligible to be presented with the content item from a publishing user, different sets of users having one or more differing characteristics;
• identify users in each set based on characteristics of users maintained by the online system;
• determine likelihoods of users in each set performing each of one or more actions when presented with the content item by applying a model corresponding to each of the one or more actions to identified users in each set;
• select an action for each set based on the determined likelihoods;
• and
• present information identifying each set of users in association with the action selected for each set of users to the publishing user.