Incremental Clicks: The Impact of Search Advertising

In this research, the authors examined how the number of organic clicks changed when search ads were present and when search ad campaigns were turned off. The authors developed a statistical model to estimate the fraction of total clicks that could be attributed to search advertising. A meta-analysis of several hundred of these studies revealed that more than 89 percent of the ads clicks were incremental, in the sense that those visits to the advertiser's site would not have occurred without the ad campaigns.