An access analysis system obtains data about user requests to access particular applications, such as identifiers of the particular user and application involved, the time of the request, and (optionally) additional contextual data, and uses that data to generate user access distributions that quantify the distribution of a given user's requests to access applications over time. After one or more distributions have been generated for a particular user, when that user submits a new access request for an application, the access analysis system can compare the request to the previously-generated access distributions to determine whether (or to what degree) the request is anomalous. If the request is sufficiently non-anomalous, it can be granted with little or no additional actions required by the user or the user's device; if, however, the request is sufficiently anomalous, it can be denied, or additional information—such as additional user authentication factors—can be required.