Med-arb has features of both mediation and arbitration. The parties first try to resolve their disputes through mediation. If that does not resolve it, then the process switches to a binding arbitration. For a more expansive introduction to med-arb, see this blog post from the HLS Program on Negotiation: "Med-arb": An Effective Tool for Resolving Disputes.
In arb-med, the process starts with an arbitration proceeding, after which a non-binding arbitration award is issued. Then, the parties work with a mediator to attempt to resolve their conflict.
Below is an article available on the internet on this topic.
There have been significant developments in med-arb in non-U.S. jurisdictions. A selection of recent articles about these developments is provided below.