In a method of monitoring a group of credential processing devices, credential substrates are processed using the credential processing devices of the group. Next, event outputs are received. Each event output relates to an occurrence of a process event during the processing of the substrate by one of the devices. Finally, a relative condition score is calculated for a subject device of the group based on the event outputs corresponding to the subject device and the event outputs corresponding to the other devices in the group. The relative condition score of the subject device is a measure of a condition of the subject device relative to the conditions of the other devices in the group. Also disclosed is a system configured to perform the above-described method.