Automated analysis of user search behavior is provided. Data on user searches is maintained in a user search database. Relevance factors are determined for each search result included in a given search session where the relevance factors provide an indication of user satisfaction with particular search results included in the session. The relevance factors for each search result are analyzed by a relevance classification module for classifying each search result in terms of its relevance to an associated search query. The result of the relevance classification may assign a relevance classification and associated confidence level to each analyzed search result as to whether the search result is acceptable, unacceptable or partially acceptable relative to the search query that resulted in the search result. Relevance classifications for each analyzed search result may be stored for future use, for example, for diagnostic analysis of the operation of a given search mechanism.