There is a related question on MSO about cross-posting: Block migration of exact duplicates. However, my concern is not with cross-posting, but rather with questions that fall under this specific set of circumstances:
- It is asked asked only on one site
- It is off-topic on that site
- It is on-topic on another site in the SE network
- I, as a potential flagger, know that it is both on-topic on another site AND a duplicate exists there from another user (not cross-posted)
I see a few options:
- Flag for migration. This makes more work for the target site community.
- Flag as blatantly off-topic.
- Don't flag, just leave comment pointing OP to dupe on target site and request they delete the current question. This relies on the OP to clean up after themselves, which I don't think is reliable since they asked an off-topic question in the first place.
- Flag for moderator and describe the situation. I think this move would be overkill. A moderator shouldn't be required to handle this situation.
What is the recommended action when I know a question belongs on another site, but I also know it's a duplicate there?
Update: I chose to flag for migration, and now my link points to the migrated question on MSO. I suppose that choice was acceptable since it was indeed migrated, but it still seems silly to create more work for the target site community when I already know it's going to need to be flagged as a duplicate.