This decision reverses a judgment dismissing the plaintiff’s petition to vacate an arbitration award. Plaintiff represneted herself in the arbitration of her complex medical malpractice claim. Toward the end of the arbitration, the arbitrator had a private conversation with defendant’s counsel in which he expressed amazement that a pro per would try to bring such a claim and commiserated with defendant’s counsel at the difficulties thus created. The conversation, which plaintiff’s mother recorded, included a laugh at plaintiff’s expense. The Court of Appeal holds that while an arbitrator is not biased merely because he finds a party or counsel unpersuasive, holding an ex parte conversation with one party is misconduct and given the nature of what was said in this ex parte conversation, a reasonable person could conclude that the arbitrator was biased against the plaintiff. The arbitrator owed a duty to reveal this potential bias, and when he failed to do so, the resulting award could not stand.