It’s not a matter of “if” one of your panelists on your panel discussion will ramble off-topic. It is when it will happen. Especially when moderating a virtual panel discussion, you don’t have the lower level intervention strategies of eye contact and movement that can get them to closure.
So why not be prepared for the inevitable?
If someone is dominating the discussion, Angela DeFinis recommends that you “watch the person’s natural breathing rhythm and then interject between breaths, ‘Thank you, Julie. Now let’s hear Bob’s perspective on this topic.’”
But then again, you can uber-prepare by asking the panelists what “cutoff phrases” they respond to. Tell them you will use this tactic for keeping the panel discussion focused and on time.