An apparatus, and related method, for identifying one or more association variables is described. The apparatus includes at least one processor, at least one memory, and at least one program module stored in the memory configured to be executed by the processor. The program module includes instructions for selecting a subset of temporal onsets in a set of temporal onsets, instructions for determining a statistical relationship between the subset and a pattern of occurrence of a variable, and instructions for identifying the variable as an association variable in accordance with the statistical relationship. The subset includes one or more first temporal onsets corresponding to one or more instances of an event, and the set of temporal onsets includes the subset of temporal onsets and one or more second temporal onsets corresponding to one or more instances of a reoccurrence event.