When a contract provides that a third party (such as an engineer) will determine whether a party has sufficiently performed the contract, the third party’s decision is conclusive and binding on the parties in the absence of bad faith, fraud, or gross negligence.  Here, to settle prior litigation, three landowners agreed that they would each remediate a mudslide on their own property and obtain from their own design engineer or geologist a report that the work had been performed in substantial compliance with the parties’ plan.  After the work was done, defendants obtained a report from their engineer stating that their work had been substantially completed in accordance with the approved plans.  This decision holds that the report barred one of the neighboring owners’ suit for breach of the prior settlement agreement.