The duplicates on the CMDB Dashboard are derived from CIs that are tagged with the discovery source field of duplicate. When this happens, a de-duplication task record is created listing or grouping all the duplicate CIs.
A CI is tagged as a duplicate either during ServiceNow discovery. During the identification phase, the IRE (hardware rule) is used to identify if the CI exists or does not exist in the CMDB to determine if an update or insert should occur. If multiple CIs exist in the CMDB as identified by the Hardware rule, then the oldest CI (in terms of creation date) is updated and its discovery source is defined as ServiceNow, however the other duplicate CI is not updated and its discovery source is flagged as duplicate. As a result of this process, a de-duplication task is created and the two CIs will display on the CMDB Dashboard under the Correctness Scorecard only after the Correctness scheduled job is run.
A second scenario exists if a duplicates exist in the CMDB and CIs do not have any discovery source defined. In this case, after the Correctness schedule job is run, these CIs will be added automatically to a de-duplication task record and also automatically be part of the calculation on the Correctness Scorecard.
