<p>Provided is a monitoring system that carries out cause analysis of an event that occurred at any of a plurality of monitoring target objects on the basis of rules. On such an occasion, the monitoring system detects during an analysis time interval, and determines a plurality of conclusions on the basis of events that meet the criteria for determining the conclusions. The monitoring system then carries out one or more of the following: (A) display of the change in the certainty factor used to determine the conclusions when it is assumed that the analysis time interval has been changed; (B) display in a sorted manner of the determined conclusions on the basis of an index value indicating a range of influence; and/or (C) calculation of the analysis time interval on the basis of the index value.</p>
