Advertisers and researchers use tools provided by advertising platforms to conduct randomized experiments for testing user responses to creative elements in online ads. Internally valid comparisons between ads require the mix of experimental users exposed to each ad to be similar across all ads....

Online advertising campaigns often consist of multiple ads, each with different creative content. We propose a model that evaluates the effectiveness of each creative in a campaign given the targeted individual’s ad impression history, as characterized by the timing and mix of previously seen...