For Eligibility AutoSync (EAS), you need a unique, unchanging External ID for every person in the file (employees and dependents) when dependents are included.
If you don’t have unique dependent IDs today, the main options are:
1) Have the file provider generate dependent External IDs (recommended)
External IDs can be numeric or alphanumeric, and you can typically make them by concatenating existing fields (e.g., employee/member ID + dependent suffix/code, or employee ID + relationship code, etc.). This is the most common path.
2) Hint can help to generate External IDs
If the feed can’t supply unique dependent IDs, Hint can help to generate a unique External ID from two columns supplied by the fie provider (commonly “member code” + “dependent code”).
Note: this can add a week or more to file configuration timeline.
3) Can you use SSN as the dependent External ID?
We strongly prefer not to use SSN as the External ID as it introduces security concerns. Also, SSNs can be missing/blank for some dependents, and using SSN can create downstream headaches.
External ID = a generated ID (from existing non-SSN fields from file provider)
SSN = sent in the SSN column when available (blank when not)
4) If none of the above is possible
Then the realistic fallback is: don’t include dependents in the AutoSync feed (employee-only feed), because without a stable unique ID per dependent, matching and updates will be unreliable.