Mediation-Arbitration like the name suggests, it’s a hybrid of 2 processes, mediation and arbitration. I really believe this to be one of the best kept secrets for families. You use the same professional as both the mediator and arbitrator. The idea is that you mediate as many of the issues as you can (retaining full decision making power) and then move forward with arbitration (where the arbitrator makes a legally binding decision for you) only for those issues that remain outstanding.
Keeping the same professional allows continuity and flexibility, while still getting finality at the end of the process.