I don't think there's a sure-fire way to know, but you can ask upfront (even in the initial communications by email or phone) if it's a new position, or a "back

I don't think there's a sure-fire way to know, but you can ask upfront (even in the initial communications by email or phone) if it's a new position, or a "backfill." And during the phone or in-person interview you can ask questions about team dynamics, like who you report to and are working with, how long the interviewer has been working there and how they like it, etc., to try to get a sense for how things work. And I'd say ask as many questions as you can reasonably think of--it's more about how they answer questions than the answers themselves. If they show resistance or evasiveness, then that may be a bad sign.