A mediator I know was explaining his system of taking and cataloging notes from his mediation sessions, to help him learn what was working and not working. He writes down phrases he has used that seem particularly effective, and keeps them on note cards. And he sometimes thumbs through his stack of cards during subsequent mediations to see if he can find something useful.
According to this mediator, impasse does not exist. Instead, when parties get stuck, he prefers to tell them only that the dispute probably will not settle that day, preserving the hope that it will settle at a later time when the parties are ready.
I have also found that the concept of impasse is not particularly helpful. It’s too simplistic, for one thing, as there are a wide variety of situations in which negotiations can get bogged down. For example, the parties may need more information before they will move off their positions. Or one or both sides may be refusing to budge for tactical reasons. Or the appropriate decision-maker needs to be consulted before additional concessions can be made. If we use the term “impasse” to describe all these different scenarios, the term doesn’t have much meaning. Moreover, the term “impasse” doesn’t provide any guidance for moving the negotiations forward. It suggests instead that the process has reached a dead end.
If you have a stack of note cards or some other tools available to show the parties some ways to keep the process moving, you have no reason to suggest to them that they have reached an impasse. Instead, just pull out another card.