To quickly establish an inferring result when a problem is detected in an operation management system equipped with a rule-based inference processing function, there is provided a method of collecting information for managing a computer system equipped with a plurality of devices. The computer system holds rule for associating a plurality of events with a conclusion output when all of the plurality of events have been detected. The method includes: executing, at a first interval, polling to obtain information indicating whether each of the plurality of events has been detected; judging whether the plurality of events have been detected; and executing, upon judgment that at least one of the plurality of events has been detected and none of the remaining events have been detected, before execution of next polling at the first interval, polling to obtain information indicating whether at least one of the undetected remaining events has been detected.