To save time and money, experts are often provided mediation briefs to be used as predicates for their testimony. Such briefs are typically the most comprehensive summaries of the case. However, taking this short cut could get your expert disqualified, costing you and your client more in the long run.

California’s Supreme Court has made clear that our broad mediation confidentiality statutes are strictly enforced. See Cassel v. Superior Court (2011) 51 Cal.4th 113; Evid. Code § 1115, et. seq. With very limited statutory exceptions, communications and writings prepared or made “for the purpose of, in the course of, or pursuant to, a mediation….” are confidential and not discoverable or admissible in a legal proceeding, even after mediation concludes. Evid. Code §§ 1119(a)-(b), 1126.

An expert cannot base his or her opinion on matter(s) “precluded by law.” Evid. Code § 801. When an expert has relied on privileged material to formulate an opinion, the court may exclude his or her testimony as necessary to enforce the privilege. Fox v. Kramer (2000) 22 Cal.4th 531, 539-541.

Mediation confidentiality serves as an evidentiary exclusion, not a privilege. In contrast to the attorney-client privilege, mediation confidentiality cannot be unilaterally waived. Evid. Code §§ 912, 952–954, 1115 et. seq.; Simmons v. Ghaderi (2008) 44 Cal. 4th 570, 585-588.

Although no California decision is precisely on point, Michigan federal decision, Irwin Seating Co. v. International Business Machines Corp., 2007 WL 518866 (W.D. Mich. 2007), underscores the proscription. In Irwin Seating, plaintiff provided its experts with defendants’ mediation brief. The district court adopted the findings of the magistrate judge, who granted defendants’ motion to strike plaintiff’s two experts based on improper disclosure of confidential mediation statements and exhibits the experts reviewed in forming their opinions. Id. at 1. Although both experts claimed they did not remember the parties’ mediation positions, the court excluded their testimony because “… there are simply some things that cannot be forgotten once they are learned.” Id. at 3. According to the magistrate judge, striking an expert witness is harsh, but not unfair where a party has placed its experts at risk by infusing them with knowledge they were not entitled to. Id. The district court adopted the magistrate’s conclusion: “… the facts upon which an expert relies are not required to be admissible. However, the factual basis for the expert’s opinion is subject to inquiry and cross-examination. Fed.R.Evid. 703. Because the information in issue is confidential, Defendants will be unable to fully challenge the experts’ assertions that their opinions were not influenced by confidential settlement knowledge.” Id.

The Ninth Circuit found that the plaintiff could recover monetary sanctions against defendants who had improperly disclosed confidential mediation documents to their experts. Tokerud v. Pacific Gas & Elec. Co., 25 Fed. Appx. 584 (9th Cir. 2001) (unpublished). Plaintiff’s request to exclude defendants’ experts’ testimony based on the improper disclosure, however, was moot because the court did not rely on their testimony in granting summary judgment.

Kendra L. Basner is a partner in the San Francisco office of Hinshaw & Culbertson.  Her practice focuses on professional liability litigation, with an emphasis on legal malpractice defense. She also advises lawyers and law firms on legal ethics and risk management.