Various aspects of the performance of computing resources, such as storage volumes, are measured and used to train a probability model. The probability model is used in a query engine that is able to respond receive queries about a computing resource's state. The queries may specify a state of the computing resource and provide a set of measurements of the computing resource's performance. The query engine may use the probability model, which may be in the form of a contingency table, to provide information that indicates one or more most likely causes of the state.