Abstract: An online system maintains characteristics for its users and may access characteristics of users maintained by a third party system. The online system may select content for a user of the third party system based on characteristics maintained by the third party system. If the third party system does not maintain a characteristic for its users, the generates a model predicting the characteristic for third party system users based on a set of online system users identified based on characteristics of third party system users. The online system clusters third party system users based on the predicted characteristic for other third party system users connected to the third party system user. Using verified characteristics for third party system users from a trusted third party system, the online system determines an accuracy of the predicted characteristic for third party system users in a cluster.

Abstract: An online system determines a metric indicating whether presenting a content item to various users increased a likelihood of other users performing a specific action associated with the content item. To determine the metric, the online system identifies a control set of users who are not presented with the content item and determines measures of affinity for users of the control set with other users of the control set and for users to whom the content item was presented. Based on measures of affinity for users of the control set and for users who were presented with the content item, the online system identifies segments of users of the control set having different measures of affinity for users of the control set and for users presented with the content item. The online system determines the metric bases on occurrences of the specific action by users in different segments.

Abstract: An online system provides content items to target users who are identified to have high incremental likelihood of performing conversion actions when presented with content items. The incremental likelihood represents the difference between the response likelihood of performing conversion actions when a content item is presented to a user, and the baseline likelihood when a content item is not presented to the user. The baseline and response likelihood for a user are predicted by one or more machine-learned models. By targeting the content to users that are likely to have a high incremental likelihood, the online system provides content items to users whose conversion actions are more likely to be impacted by the presentation of content items, rather than users that may just be of interest for performing the action.

Abstract: An online system maintains characteristics for its users and may access characteristics of users maintained by a third party system. The online system may select content for a user of the third party system based on characteristics maintained by the third party system. If the third party system does not maintain a characteristic for its users, the generates a model predicting the characteristic for third party system users based on a set of online system users identified based on characteristics of third party system users. The online system clusters third party system users based on the predicted characteristic for other third party system users connected to the third party system user. Using verified characteristics for third party system users from a trusted third party system, the online system determines an accuracy of the predicted characteristic for third party system users in a cluster.