Important Tips for Cases in Both State and Federal Courts

Just as important as making sure you pick the right expert, your counsel also needs to know how to handle your adversary’s expert.  Chances are that your lawyer is not a chemical engineer, doctor, or forensic accountant.  And they probably don’t have time to pick up that extra graduate degree while also preparing for your case.

So, accepting that the other side’s expert will know more about their own area of your expertise than your lawyer will, what can your lawyer do to get up to speed on the subject matter, learn everything they need to know about the other side’s expert, and then figure out how to dismantle that expert’s opinions?

Thankfully, there is both an art and science to examining experts, and the best lawyers know this and have been developing their craft since leaving law school.

Learn All You Can About the Expert

As with many things in the law, first comes the research.  Once the parties disclose their testifying experts, your lawyer needs to learn everything they can about your opponent’s expert.  The expert’s CV and list of publications — which must be disclosed in both California state court cases and federal court cases as part of expert disclosure — is just the starting point.  Your attorney should begin by researching the expert’s credentials to test whether they are qualified to give the sorts of opinions they are expected to render.  Someone testifying outside their area of education, training, and experience can be excluded as an improper expert.

Experienced counsel will identify the expert’s past cases in which they’ve testified, and then research whether the expert was ever excluded from testifying (because a judge found the expert’s testimony to be irrelevant, unreliable, or not based on generally accepted scientific principles), or had their testimony struck or limited (again, for the same types of reasons).  An expert whose testimony was excluded before trial or limited at trial can be devastating to their credibility.  It can also help your attorney lay the groundwork for why that expert’s testimony will be unreliable, why they should not be permitted to testify in your case, and, if they do testify, why the jury should disregard their opinions.

Even if the expert’s credentials look solid and they have never been excluded before, there are still many avenues that could lead to undermining their testimony.  Your attorney should examine the past testimony the expert has given at deposition or trial to see if the expert has ever taken positions contradicting the ones they’re expected to take in your case.  The expert’s prior publications are another place to scour for potential instances where the expert took the opposite position from what they intend to say in your case.

An expert flip-flopping can seriously damage their credibility with the jury.  Even if the subject of the testimony is very complex, the jurors understand what it means for someone to offer totally inconsistent opinions.  At best, the expert looks unreliable.  At worst, they seem like a hired gun who will give whatever answer they are paid to give.

Learn All You Can About the Expert’s Opinions

Finally, we turn to the expert’s opinions for your case.  Lawyers who have handled many cases with similar fact patterns may have developed their own ability to interpret expert data and analysis without assistance.  Through years of practice, they have learned to hold their own against credentialed experts in debating how damages should be calculated so as not to be speculative, or they’ve become adept at reading X rays even if they’re not a radiologist.  But in many instances, you and your lawyers will have to deal with subject matters that you don’t have a deep background in.  That won’t stop a great lawyer from learning how to take on even well-respected experts in the field.  They will know, however, that they can’t do it alone.

Lean on Your Own Experts

This is where your own experts come in.  In federal court, where attorneys and their retained experts enjoy privilege over their communications (meaning the other side doesn’t get to ask for the lawyer’s emails and memos back and forth with the expert), your testifying expert is likely to be your attorney’s best ally in preparing to examine the other side’s expert.  You’ve already hired a great expert who can explain complex concepts to the jury, so the first time to try out those skills will be when they help your attorney assess and critique the opposing expert’s opinions.  Your expert can help point out the weaknesses and unreasonable assumptions in the other side’s expert report, can also attend your attorney’s deposition of the other side’s expert, and can even help your attorney prepare for the deposition by formulating the right questions to get the precise answers you’ll need.  Your expert’s attendance at the deposition can be helpful as well, since your expert can help your attorney assess in real time whether the opposing expert’s testimony is credible and scientifically sound.

What About in California State Court?

California state court expert rules differ substantially from the federal rules.  First, in most state cases, expert disclosures happen much later in the case than they do in federal court, meaning you have less time to prepare to examine the other side’s expert.  Second, expert disclosures in California state court tend to be less substantive than federal disclosures; instead of a robust expert report you can examine the expert about, the California rules require only a brief statement of the general substance of the expert’s expected testimony.  This is far less material for your attorney to work with.  Finally, there is no privilege between testifying experts and attorneys in California, meaning your lawyer must be careful if they want your testifying expert to help them prepare for the opposing expert’s deposition, because any documents they share or prepare for that purpose could then become discoverable by the other side.  Instead, you may need to hire a consulting expert for the express purpose of assisting you and your counsel in understanding the opposing expert’s opinions.  The consulting expert is rarely disclosed, and the consulting expert’s communications with the lawyer are confidential and are not discoverable by the other side.


Examining opposing experts well requires that attorneys have the discipline and curiosity necessary to learn a great deal of new information quickly. Many great lawyers will agree, however, that examining opposing experts is one of the most challenging and rewarding parts of litigation.

Our attorneys put their years of experience across a broad range of cases and subject matters to work to make sure you achieve the best results possible.  Bring us your toughest case, we’ll get the job done.