Abstract: Methods, systems, and apparatus for selecting content items based on presentation context are presented. In one aspect, a method includes for each of a plurality of content item slots of a resource: obtaining first performance data based on a performance of content items that were presented in a navigational context in the content item slot; obtaining second performance data based on a performance of content items that were presented in a non-navigational context in the content item slot; determining, from the first and second performance data, a navigational performance adjustment factor for the content item slot, the navigational performance adjustment factor indicating, for the content item slot, a performance of content items presented in the navigational context relative to a performance of content items presented in the non-navigational context.

Abstract: Methods, systems, and apparatus for selecting content items based on presentation context are presented. In one aspect, a method includes for each of a plurality of content item slots of a resource: obtaining first performance data based on a performance of content items that were presented in a navigational context in the content item slot; obtaining second performance data based on a performance of content items that were presented in a non-navigational context in the content item slot; determining, from the first and second performance data, a navigational performance adjustment factor for the content item slot, the navigational performance adjustment factor indicating, for the content item slot, a performance of content items presented in the navigational context relative to a performance of content items presented in the non-navigational context.