Choosing a source of truth field by field

Why does one source never win outright?

Every tool sees an asset from its own angle. The MDM knows the serial number and the enrolled user. The EDR console knows whether its agent is running. The directory knows the account and the department. The cloud provider knows the instance type and region. Asking which tool is the source of truth for the whole record forces you to accept its blind spots.

What does field-level precedence mean?

It means writing down, for each field in the record, which source is trusted first, which is the fallback, and what happens when they disagree. A short example:

• Serial number: MDM first, then discovery.
• Assigned user: identity directory first, then MDM.
• Operating system version: EDR or agent data first, then network discovery.
• Location: network discovery for on-site devices, MDM for remote ones.
• Owner team: HR or the service catalog, never a guess from the hostname.

The exact order depends on your tools. The point is to decide it once, on paper, before anyone configures a connector.

How do vendors describe this?

ServiceNow's CMDB page talks about curating data from multiple sources through certified Service Graph Connectors. Oomnitza describes reconciling procurement, MDM, EDR and ITSM. Axonius correlates data from its adapters into one record per asset, and its CMDB Reconciliation Workspace, announced in July 2026, flags field values that differ between the CMDB and the correlated data. Each describes the same idea at a different level of detail.

What about conflicts that rules cannot settle?

Some disagreements are signals, not errors. A laptop that the MDM says is active but the EDR has not heard from in thirty days may be lost, or may have had its agent removed. Those cases should become tasks for a person, not silent overwrites. A good setup lists them so someone can look.

How does this show up in our scores?

Data trust and reconciliation carries 20% of the weight in our method. Options score higher when their pages describe merging several sources and resolving conflicts; Axonius leads at 90. Options that mainly fill the record from their own discovery have fewer sources to reconcile and score lower on this criterion, which is a property of the design rather than a flaw.

What should you do first?

List the ten fields your workflows depend on most, name a first and second source for each, and note what you will do when they disagree. That one page saves weeks of argument later.