An advertising simulation system performs simulation of advertising results. The advertising results indicate the results of a simulated auction for a set of ad queries that are provided advertisements from available advertisements. The simulated auction applies an advertising model to perform an auction using advertising conditions. As advertisers are selected to provide advertisements to individual ad queries, advertising conditions, such as advertiser's bidding amounts, may change. To effectively simulate a large number of ad queries, the advertising segments simulation and performs simulation of each segment. Each segment's ad results may affect the conditions of a subsequent segment, and the change in conditions may change the size of a subsequent segment.