1. A method of collecting information for managing a computer system, wherein the computer system comprises a plurality of devices, and a management computer being configured to communicate with the plurality of devices, the method conducted by the management computer comprising: holding, in a memory accessible by the management computer, rule information including a first rule indicating a first conclusion that is output when all of a first plurality of events have been detected, and a second rule indicating a second conclusion that is output when all of a second plurality of events have been detected, regularly polling the plurality of devices to obtain first information related to the first plurality of events and second information related to the second plurality of events; calculating a first ratio based at least in part on events of the first plurality of events that were detected by the regularly polling; calculating a second ratio based at least in part on events of the second plurality of events that were detected by the regularly polling; and conducting additional polling with respect to at least one of the plurality of devices to obtain one or more undetected events of the first plurality of events or the second plurality of events, based on the first ratio and the second ratio.