As is the nature of litigation, plaintiffs and defendants often view a case differently. Whether an issue does or does not require expert testimony is no exception. A plaintiff may think that expert testimony is required on an issue that defendant thinks requires no expert testimony at all. So, not surprisingly, the plaintiff may disclose an expert on an issue that the defendant does not disclose an expert on. What happens if the defendant (or plaintiff if the tables were turned) now wants to supplement their expert disclosure? 

California Code of Civil Procedure Section 2034.280 allows for the supplemental exchange of experts. Subsection (a) provides that “[w]ithin 20 days after the exchange described in Section 2034.260, any party who engaged in the exchange may submit a supplemental expert witness list containing the name and address of any experts who will express an opinion on a subject to be covered by an expert designated by an adverse party to the exchange, if the party supplementing an expert witness list has not previously retained an expert to testify on that subject.” 

Section 2034.260(a) provides that "[a]ll parties who have appeared in the action shall exchange information concerning expert witnesses in writing on or before the date of exchange specified in the demand" and subsection (b) describes the exchange as either "(1) [a] list setting forth the name and address of any person whose expert opinion that party expects to offer in evidence at the trial" or "(2) [a] statement that the party does not presently intend to offer the testimony of any expert witness."

Thus, the plain language of the statutes allow a party to submit a supplemental expert witness list within 20 days of the initial list exchange if three criteria are met: (1) the party participated in the initial exchange by either (a) providing a list setting forth the name and address of any person whose expert opinion the party expects to offer in evidence at trial or (b) providing a statement that the party does not presently intend to offer the testimony of any expert witness; (2) the supplemental expert will opine on an issue "covered by an expert designated by an adverse party to the exchange"; and (3) the party listing the supplemental expert "has not previously retained an expert to testify on that subject." When these criteria are met, you should be home free and able to supplement your expert disclosures. 

Even if you satisfied these statutory requirements, your opponent may still argue that you should have anticipated their expert and thus you are barred from supplementing. 

Your opponent will cite Fairfax v. Lords, 138 Cal. App. 4th 1019 (2006), but your case will likely be distinguishable. 

First, in Fairfax, the court's finding that the defendant had violated the statute governing witness designations relied on the fact that the defendant had violated the "requirement of a 'simultaneous' exchange" (i.e., CCP Section 2034.260(a)): "[Defendant's initial] list includes not a single name of any witness Lords 'expected' to call." Defendant also did not provide a statement that it did not intend to offer the testimony of any expert witness. Point out your compliance with Section 2034.260(a). 

Second, the defendant's counsel admitted it was his intent to hold back expert designations until he saw the plaintiff's expert list: "The effect of Lords' expert designation was to delay his own list of 'expected' witnesses until after he had seen the list put forth by Fairfax. Lords does not deny that this was his express intent, and instead argues it is only 'prudent' for a defendant to do so." Of course, you should not intend to sandbag your opponent, and you should make that clear to the court. More importantly, you should explain how you could not have planned the alleged sandbagging. 

Regardless, some courts will rely on Fairfax and deny the supplementation even when the code of procedure has been diligently met. Therefore, when you are preparing for expert discovery, you should consider very carefully not just which expert you need to prove your case, but who you think the other side might want to prove their case. If there is even a chance that the other side will disclose an expert that you have no interest in disclosing, but you would want the chance to respond (with your own expert) to their expert, then think very hard about whether you will disclose someone instead of taking your chances and waiting to supplement. You may be worried about opening the door to their supplemental expert disclosure. That is a genuine risk to consider. But, you should also be concerned about a judge slamming the door on your expert.

This article was also published in the Daily Journal on March 4, 2015.