A method to determine an operating status of an image forming device comprises: monitoring a plurality of operating parameters of the image forming device during a first time interval; calculating a correlation coefficient during a second time interval between at least two of the plurality of operating parameters; identifying the image forming device as an abnormal operating status when the correlation coefficient calculated during the second time interval is a positive correlation coefficient above a predetermined level associated with a model of the image forming device; and determining a maintenance action for the image forming device based on the abnormal operating status.