Why Do Two Data Sources Use the Same Customer ID for Different People?

Identifiers may be unique only within one system or may be recycled over time. Joining records on the ID alone can combine unrelated people and distort customer history.

What to check

Confirm identifier scope and lifecycle, source system, tenant, and effective dates. Trace affected joins and compare with trusted attributes without exposing personal data.

Recommended next step

Use a properly scoped key or mapping table and reconcile affected records. Informatix Systems can assess data integration and analytics quality.