Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for using second screen devices to augment media engagement metrics. In one aspect, a method includes accessing user activity data describing user activities performed by a user on a first user device during a first time period, and accessing data describing presentation of one or more content items during the first time period on second user devices. For the first user device, determining based on the user activity data, for each of a plurality of second time periods that are sub-periods of the first time period, a first level of user engagement with the first user device, and determining, based on the user activity data, for each second time period that is a sub-period of the first time period, a second level of user engagement with the one or more content items presented.