Accounting for online system user actions occurring greater than a reasonable amount of time after presenting content to the users when selecting content for users

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

• receive one or more content items at an online system for presentation to users of the online system;
• maintain information describing presentation of a set of the received one or more content items to users of the online system at the online system;
• receive information from a third party system associated with a content item of the received one or more content items describing actions performed by users of the third party system, the information including information identifying one or more performed actions, values of the one or more performed actions to the third party system, and information identifying users of the third party system who performed the one or more actions;
• identify users of the online system corresponding to the information identifying users of the third party system who performed the actions;
• determine information describing presentation of the content item to the identified users of the online system;
• generate a model predicting a value to the third party system of presenting the content item of the received one or more content items based on the information describing presentation of the content item to the identified users of the online system and the received values of the one or more performed actions, the model generated by applying one or more weights to one or more likelihoods of a user of the online system performing one or more actions after being presented with the content item and combining the one or more weighted likelihoods to determine the value to the third party system of presenting the content item of the received one or more content items to the user of the online system;
• identify an opportunity to present content to a viewing user of the online system;
• and
• include the content item of the received one or more content items and the predicted value to the third party system of presenting the content item of the received one or more content items determined based on the model in one or more selection processes selecting the content for presentation to the viewing user.