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Rules of (Expert) Engagement

by Carl Ciochon

[Reprinted with permission from the December 17, 2012 edition of The Recorder © 2012 ALM Media Properties, LLC. All rights reserved. Further duplication without permission is prohibited.]

Some years back, there was a book about the importance of the stuff we learned in kindergarten. That concept has absolutely no application here. Everything I know today about presenting and cross-examining expert witnesses I learned in conference rooms and courtrooms. These lessons I put in five categories.

Don't Choose The Wrong Expert

Choosing the right expert will not guarantee a win for your client, but choosing the wrong one can surely lead to defeat. My two imperatives for avoiding the wrong expert are:

  1. The expert must believe in the opinions she will offer.
  2. Those opinions cannot be inconsistent with the expert's prior writings, testimony and business practices.

This first point was a hard lesson learned. Years ago, I engaged a defense expert to testify concerning industry standard sales executive compensation criteria. The expert had outstanding credentials and was recommended by a member of the client's board of directors. Preparing for trial, we walked through a hypothetical: "Assuming facts x, y and z — in your opinion, did plaintiff's efforts meet industry standards for compensation on this account?" In our prep sessions, the expert dutifully followed our lead, consistently responding with the desired "no." But under oath, he had an apparent crisis of conscience, and gave exactly the opposite answer.

How could we have avoided this fiasco? I am convinced today that our error lay not in preparation, nor in examination, but rather in selection. The lesson? When interviewing potential experts, avoid telegraphing the desired opinion. Lay out the facts objectively. Ask open-ended questions to elicit the expert's honest views. Test the boundaries of the expert's preliminary opinion by changing the facts. If this process suggests that the expert's views are not compatible with the fundamentals of your case, find a different expert.

Conducting thorough due diligence into a prospective expert's prior writings, testimony and business activities is likewise essential. In a case where the availability of long-term financing during a particular time period was at issue, our adversary engaged an Ivy League professor to opine that financing was not available. The expert's CV showed that he served on the board of a well known REIT. We pulled the REIT's SEC Form 10-K off the Internet. It disclosed that the REIT had obtained tens of millions of dollars in long-term financing during the very same period. More thorough due diligence by opposing counsel would have deprived us of the immensely entertaining cross-examination that followed.

Let Your Expert Be The Expert

Trial lawyers like control. It is in our nature and part of our job description. When it comes to experts, our desire to control can cause problems. The expert probably knows more than we do about the subject of her expertise and — if allowed sufficient freedom — can provide a new and valuable perspective on the case. Odds are as well that the expert takes pride in her expertise, and may resent a lawyer's efforts at micromanagement. Letting the expert be the expert is thus key to a successful engagement. This means:

  • Encouraging the expert to conduct her own preliminary analysis rather than imposing rigid guidelines.
  • Working together with the expert to (1) refine preliminary conclusions into formal opinions and (2) anticipate subjects of cross-examination.
  • If necessary, adjusting the case based on the expert's input (rather than insisting the expert alter her opinions to fit the lawyer's preconceived views).

This does not mean that we give our experts free rein. The lawyer bears ultimate responsibility for trial presentation, and should pay particular attention to two issues. First, is the expert's opinion consistent with the evidence on which it is based and established scientific norms? If not, it will be subject to exclusion. Second, has the expert expressed the opinion at a level that will be readily understood by the trier of fact? Here, the best practice is to have your expert present a summary of her opinions to a non-lawyer (and nonexpert) to ensure that the message is being clearly conveyed.

Don't Give The Bad Guys Any Free Shots

These are fundamental rules, already well-known to experienced practitioners, but sufficiently important to bear repeating:

  • Do not show, give or tell your expert anything that you would not want opposing counsel or the trier of fact to see or hear.
  • Do share with your expert all relevant facts and documents; an opinion that's based on an incomplete record will be discredited by a competent adversary.
  • If you are in superior court, discuss preliminary conclusions with your expert before anything is put in writing; all writings are potentially discoverable, and your opponent will likely cite any substantive changes as proof the opinion was crafted by the lawyer. (Note that under recent amendments to Rule 26(b)(4), draft reports are no longer discoverable in federal court.)

Allow Your Expert To Be A Teacher

The trial judge will generally allow you to lead your own expert. But this is not a recommended practice. A string of "yes" and "no" answers from your expert will have minimal persuasive value. Far better to let your expert show her stuff. Begin with open-ended questions. "What did you do to familiarize yourself with the case?" "What opinions did you form?" "What are those opinions based on?" Then drill down with increasingly specific follow-up questions. If the expert uses terms of art, stop and ask her to define them. Ask why she did things the way she did. Ask her if she considered alternative approaches, and if so, why they were rejected. The goal of the expert exam is not merely to elicit opinions to support your case, but to establish your expert's mastery of the subject matter, competence and credibility. Letting your expert be a teacher will accomplish just that.

Expert Cross-Examinations Are Special

Treating your cross-examination of the adversary's expert as if it were just another cross is almost always a mistake. These are my rules for expert cross-exam:

Ensure against surprise: To avoid being surprised with new opinions at trial, ask the proper "lockdown" questions in deposition: "Do you intend to offer at trial any opinions you have not expressed here today?" "Do you intend to do any further work on this case?" "If you do form additional opinions, will you notify us in advance of trial?" See Jones v. Moore, 80 Cal.App.4th 557 (2000).

Object, or forever hold your peace: In a case involving a trespass claim, our expert presented a rather creative theory for calculating the rental value of unimproved land. There was no objection. In affirming a judgment that the reasonable rental of our client's vacant land was $27,775 per month, the court of appeal held that defendant's failure to object constituted a waiver of any challenge to the trial court's determination.

Set realistic goals: Experts are professional witnesses. Your ability to score points may be limited. Read everything. Because it's often difficult to challenge an expert opinion head-on, highlighting omissions and inconsistencies as evidence that the expert's analysis is unfairly biased may be your best avenues of attack. Be disciplined. Make your points and get out. The longer you let a skilled expert talk, the worse things will get for you. Finally, never argue with an expert. Arguing gives the expert the opportunity to demonstrate that she is an expert in the subject matter, and that you are not.


There are few trial experiences more satisfying than presenting a compelling expert presentation or conducting a withering expert cross. Conversely, there are few experiences more deflating than watching your adversary elicit testimony from your expert that helps his case. Choose the right expert, respect your expert's expertise, follow the fundamental rules of expert prep, allow your expert to be a teacher, and remember that expert cross-exams take special care, and you will be well on your way to a positive result.