It is optional, everywhere
A missing LRN never stops a score, a computed grade, a report card, or a release. You can run a whole school year without one. Add it when the number reaches you.
Where it matters
When a subject teacher's standalone gradebook is linked to an adviser's class, the two learner lists are reconciled. LRN is tried first, exactly, before email and before names. A roster with LRNs merges cleanly; a roster without them relies on spelling.
Adding or fixing one
- Learners → Edit on the row, then Edit details.
- Type the 12 digits into LRN. Spaces and dashes are stripped, so paste it however it is written down.
- Press Save learner.
The two warnings
- An amber LRN with a warning mark means it is not 12 digits. It is recorded as typed and blocks nothing — the class overview says as much: LRN missing or not 12 digits · Never blocks release.
- Same LRN on more than one learner means exactly that. Two learners cannot share an LRN, so one of the two is a typo. Hover the number to see the note. Nothing is guessed for you, because a wrong number here would drive the wrong match on a link.
On a paste, a bad LRN is a warning, never a blocker: LRN should be 12 digits. You can leave it blank and add it later.
How it is stored
The LRN is encrypted in the database and kept out of the audit trail — the trail records only that a learner has one, never the number. Matching runs on a one-way hash, so nothing has to be decrypted to reconcile two rosters.
You still see the full number on your own roster, in the class list export, and on the report card, because those are yours. The one place it is deliberately shortened is the report card watermark, which shows the last four digits only.