Techniques for simulating performance of a content delivery campaign are provided. In one technique, multiple entities that satisfy one or more criteria associated with a content delivery campaign are identified. For each entity, multiple content item selection events in which that entity participated are identified and data associated with each of the content item selection events are aggregated to generate aggregated data. The aggregated data associated with each entity is combined to generate combined aggregated data. The combined aggregated data is adjusted based on an actual performance value of the content delivery campaign to generate adjusted aggregated data. In response to receiving input, determining, based on the adjusted aggregated data and the input, a simulated performance of the content delivery campaign.