US Patent 10051327 Determination of user perspicaciousness during a content stream

An online system predicts attention scores using a predictive model, each attention score representing a user's perspicaciousness as the user is accessing a live stream. The predictive model describes a relationship between a user's attention score and when the user joined the live stream. Therefore, when the online system receives a request to generate an attention score for a user that joined the live stream at a particular time, the online system applies the predictive model to determine a predicted attention score for the user. The online system can provide the predicted attention score to a content provider server such that the content provider server can select content items to be presented to each user during a break in the live stream. If users do not respond to presented content items as expected, the online system can update the predictive model to account for the unexpected responses.