BATNA (Best Alternative to a Negotiated Agreement) is a concept developed by Roger Fisher and William Ury of the Harvard Program on Negotiation.  It was popularised in their book Getting to Yes (Random House Business Books, 3rd edition, 2012).  It refers to the best outcome you can hope for if you fail to reach an agreement.  In essence it is about having an alternative to turn to should negotiations fail.

Importantly for the mediation process, BATNA is a way of measuring how good a deal really is.  Parties in a negotiation are influenced consciously or subconsciously by their assessment of their alternatives to a negotiated agreement.  The better their alternatives, the more they are likely to push for a more favourable agreement.  In contrast, the worse their alternatives are, the more likely they are to make concessions in trying to reach an agreement.

Sometimes parties will disclose their BATNAs during the opening joint session at a mediation but more frequently, parties will prefer to keep their BATNAs confidential until the private sessions with the mediator.  Parties will usually view this information as potentially weakening their negotiating position if the other party were to discover this.  The mediator would never disclose this information to the other party without permission by the disclosing party.  

A thorough analysis of the BATNA is often important in assisting a party to make an informed decision.  The mediator can assist the party and their representative in undertaking a thorough analysis during the private sessions.  The mediator may ask challenging questions, play devil's advocate and ask reality testing questions, particularly if inaccurate or exaggerated predictions have been made, and factors ignored.