Design of Search Engine Services: Channel Interdependence in Search Engine Results

The authors examine prominent placement of search engines' own services and effects on users' choices. Evaluating a natural experiment in which different results were shown to users who performed similar searches, they find that Google's prominent placement of its Flight Search service increased the clicks on paid advertising listings by more than half while decreasing the clicks on organic search listings by about the same quantity. This effect appears to result from interactions between the design of search results and users' decisions about where and how to focus their attention: users who decide what to click on the basis of relevance were more likely to select paid listings, whereas users who are influenced by visual presentation and page position were more likely to click on Google's own Flight Search listing. The authors consider implications of these findings for competition policy and for online marketing strategies.