1. A system comprising: one or more processing devices; and one or more storage devices storing instructions that, when executed by the one or more processing devices, cause the one or more processing devices to perform the following operations: access a first data set associated with a first group of users, the first data set including demographic data, online behavior data, and additional user data associated with the users in the first group; access a second data set associated with a second group of users, the second data set including demographic data and online behavior data but not additional user data associated with the users in the second group; group users in the first group and users in the second group into one or more subsets based on the demographic data included in the first data set and the demographic data included in the second data set; create a vector of online behavior data for each user from the first group grouped in a first subset and for each user from the second group grouped into the first subset; match a first user in the first group with a second user in the second group by: determining a distance between the vector created for the second user and each of the vectors created for the users from the first group grouped in the first subset, determining that the distance between the vector created for the first user and the vector created for the second user is smaller than the distances between the vector created for the second user and the other users from the first group grouped in the subset, and matching the first user with the second user in response to determining that the distance between the vector created for the first user and the vector created for the second user is smaller than the distances between the vector created for the second user and the other users from the first group grouped in the subset; generate, based on matching the first user in the first group with the second user in the second group, an augmented second data set that includes additional user data associated with the second user in the second group; and generate one or more reports based on the augmented second data set.