Implementations for adaptive learning include actions of: outputting a practice problem having a problem difficulty rating, in which the practice problem is identified by one or more concept tags, each concept tag relating to a different subject-matter area that forms a basis of the practice problem; receiving an answer from a user to the practice problem; responsive to receiving the answer, determining whether the answer includes a correct or incorrect response to the practice problem; responsive to determining whether the answer includes a correct or incorrect response, updating, for each of the different subject-matter areas, a corresponding user specific comprehension rating and the problem difficulty rating of the practice problem, based on whether the answer includes a correct or incorrect response; and outputting, for at least one of the different subject areas that forms the basis of the practice problem, the updated user specific comprehension rating.