What is a Kaiser Arbitration “Party Arbitrator”?

Within the Kaiser arbitration system, overseen by the Office of the Independent Administrator (OIA), parties have the option to use a single neutral arbitrator to resolve the case or for both sides to select "party arbitrators" who participate in rendering a decision alongside a neutral arbitrator. This arrangement, known as tripartite arbitration, has become less favored due to scheduling complexities, the OIA’s policy of paying the cost of the neutral arbitrator when parties waive tripartite arbitration, and the sense that party arbitrators may not have substantive impact on the final outcome.