If I vote to close, one of the options presented to me is that the question belongs on a different SE site. I don't recall seeing this option before so I assume this is a relatively new feature, which I think is a good one. However, only three options are listed (meta.MO, math.SE, and stats.SE). But I can think of at least three other sites that arise frequently (hsm.SE, cs.SE and cstheory.SE) and there are probably others (physics.SE?). Why is the list so short? Can it be lengthened?
Additional paths can only be added by SE employees, and they'll only do it when there's already enough questions being migrated and the other site is accepting a high proportion of those migrations. In the meantime you can flag for moderator attention and suggest that they migrate. If this is successful often enough we could request a new path be added (up to 4 plus meta).