The state of a system is determined in which data sets are generated that include a plurality of data instances representing states of one or more components of a computer system. The data instances generated by one or more data set sources that are configured to output a data instance in response to a trigger associated with the one or more components. The data instances are normalized by the application of one or more rules. The data instances from individual data set sources are separately collated to generate groups of time-specific collated data instances. State types may be assigned to each of the collated data instance groups. Distributions of state-types across the groups may be determined and a list of infrequent state-types may be generated based on the determined distributions of state-types across the groups.