A method and a system are provided for deducing shadow user profile attributes for ad campaigns aimed at target users. In one example, the system extracts tagged data from source data. The tagged data includes label information associated with an actual profile for a user. The tagged data is associated with the user. The system prepares the tagged data by splitting the tagged data into datasets, including at least training data and test data. The system generates one or more individual models based on the tagged data, wherein the one or more individual models provide the ability to deduce attributes of a profile for the user. The system then generates a composite model based on the individual models. The composite model includes a combination of the individual models that are associated with the user. The system may charge a premium for ad campaigns that are aimed at target users who are each assigned one or more shadow profile attribute values. The system may determine the premium based on the confidence level with which the one or more attribute values fits to the one or more users. The system is applicable to both display advertising and sponsored search advertising.