10 Ideas for Giving Effective Expert Depositions


We continue a series of posts related to expert witnessing and expert testimony.  These posts are not researched, but rather, are based on my more than 30 years of experience as an expert witness, as well as experiences observing other expert witnesses.  Lest that last statement be misconstrued, while I have testified many times over the years, I am a business valuation professional who serves as an expert witness and not a professional expert witness.  Nevertheless, I have learned a number of things over the years that help me as I try, as best as possible, to employ the ideas.

Giving an Expert Deposition

Preparations are complete and you walk into a conference room for your deposition.  Once the pleasantries are out of the way, the expert will be sworn in by the court reporter.  Then the deposition begins.  We will review a few “rules” or ideas that may be helpful for business valuation, business or economic damages, or forensic investigation experts.  The perspectives should also be helpful to attorneys as well.

Let the deposition begin….

10 Ideas for Giving an Expert Deposition

Here are 10 ideas, in no particular order, that hopefully will help you (and me) give more effective expert depositions in the future.

  1. Tell the truth.  Experts are, as noted above, “sworn in” and are obligated to tell the truth in depositions and, of course, at trial. One of my early experiences giving a deposition involved working with a very seasoned attorney. My deposition started out well, or so I thought. I was apparently trying to “win” the deposition, and was expanding on answers and waxing eloquently. At the first break, the attorney grabbed me by the arm and walked me to a remote part of the office where he gently pushed me against the wall. He took his hand off my arm and then used his finger to point at me, saying: “Dammit, Chris, you always have to tell the truth. But you don’t always have to be telling it!  Now go back in there and just answer the questions you are asked.”
  2. “Yes,” “No,” and “I don’t know” can be complete answers.  This can work a couple of ways from an expert’s viewpoint.  Counsel will often ask a series of questions and want a “yes” or “no” response from the expert.  If the answer is “no,” there can be a temptation to explain, even if none is necessary. On the other hand, it may be difficult to answer “yes” or “no” because to do so would be misleading. If allowed by the court, an explanation may be appropriate. A couple of years ago, I was in a trial where opposing counsel was legendary for requiring only “yes” or “no” answers to his questions. The judge supported him, so the expert was not supposed to explain. My direct testimony ended before lunch and the court did not allow an early break, so the attorney had to cross-examine me with no time to get his thoughts in order. He asked me the following (as close to verbatim as I can remember):

    Question.  “Isn’t it true, Mr. Mercer, that in your financial control valuation, you are forecasting that international sales will increase by $600 million over the ten-year forecast period?”
    Answer. “No.”
    Question. “Isn’t it true, Mr. Mercer, that in your strategic control valuation, you are forecasting that international sales will increase by $800 million over the ten-year forecast period?”
    Answer.  “No.”

    He just knew I would answer “yes” to both questions. However, it was not true – in the first question, international sales would increase by $600 million. The company already had almost $100 million in international sales, so the increase was only $500 million. For the second question, the increase was only $700 million and not $800 million. Had I been allowed to explain, we might have gotten into the discussion he wanted.  But I didn’t, and neither he nor his co-counsel were sufficiently confident to challenge me on the question. It threw things off for them and gave me a chance for a breather at the start of cross-examination.

    Remember, while you are an expert, you are not charged with knowing everything about any matter.  Many experts are tempted to try to answer a question, even though they may not know the answer. That is a prescription for a bad deposition testimony.  It is okay to answer a question with a simple, “I don’t know.” Even if you think you should know, don’t go off the reservation.  An answer like, “I think I’ve looked at that document before, but I do not recall it or its content at this time.” Maybe the attorney will show you the document, and then you will know.  Or maybe you can look at it later.  “I don’t know” is a complete answer many times.

  3. Speak in whole sentences and paragraphs.  In an oral deposition, the transcript is the only record of the deposition.  In a video deposition, there is also the video, but the videos are seldom used, at least in my experience. So let’s focus first on the oral deposition.  You are creating a written record in a deposition.  So avoid sloppy speech mannerisms such as “Uh-huh, “Yeah,” “Nope,” or the prefatory comment, “You know.”  Take your time to formulate your response and then speak it clearly. It is very distracting for a reader (the judge?) to read a deposition filled with sloppy speech. Just remember during the deposition that you want to create a good written record. It is okay to pause and think about your response before formulating it. Train yourself to pause without saying “uh” or something while you are thinking. The deposition transcript will reflect what you say not the pauses while you were thinking.
  4. Avoid the temptation to argue with cross-examining counsel.  It can sometimes be difficult to remain cool when under the intense fire of cross-examination by a hostile attorney. Just remember your objective: to answer each question asked truthfully. Don’t go for the bait of an argument in which you might say something you would not want in the transcript. Opposing counsel is not your friend when taking your deposition. He or she is trying to get you to say things that can be used at trial to impeach your testimony. You don’t want that to happen. Most of us quit thinking clearly when we argue. Think about some of the things you might have said when arguing with your spouse, a friend, or even a child. You don’t want that kind of argument in your deposition.
  5. Answer only the question asked.  There can be a real temptation after giving an answer, to add to a response, particularly if opposing counsel leaves a period of silence after your answer. They do this to induce you to say more. Often, the more you say, the more likely they will find a “sound-bite” they can use against you. The silence is your friend if you use it wisely. In a deposition many years ago, opposing counsel was winding down and pretty much was done. He asked me one more question that I answered, and then I did not follow the advice of waiting out the silence.  I answered more and that bit opened up an entirely new line of questions that lasted another hour.

    Don’t go for the bait of an argument in which you might say something you would not want in the transcript. Opposing counsel is not your friend when taking your deposition. – Chris Mercer

  6. Ask for breaks when you need them.  Experts are entitled to breaks.  Most attorneys are quite nice about breaks, although they may want to complete a line of questions or at least a current question prior to taking the break. The break time is your friend.  It gives you a chance to relax, get some coffee or water, walk around, and get your head back together. Depositions are intense, so be sure to take a break at least every hour.
  7. Watch for absolutes.  “So now, have you given me all of the reasons for your opinion management’s forecast was unreliable?” It is often a good idea to hedge. Deposition questions often do not follow an expert’s report. Maybe you gave three reasons in response to the question. One response to the question might be the following: “Mr. Brown, I’ve given you all the reasons I can think of right now. My report is 150 pages in length, and it is quite possible that there may be a couple of more reasons that I don’t remember right now. The report will speak for itself.”  You then have not given those reasons away or set yourself up for embarrassment at trial.
  8. You would agree with me…. In a recent deposition, questions to me were prefaced with the following words on many occasions: “Mr. Mercer, you would agree with me, wouldn’t you, that…”  Chances are when opposing counsel asks a question like that, there will be something in what follows that you (or I) would not agree to.  Watch questions like that to be sure you fully understand them.
  9. Watch for hypotheticals.  Hypothetical questions are used extensively in medical malpractice cases to frame a set of facts and then, to elicit expert testimony based on those facts. In business valuation, damages and forensics cases, hypothetical questions are often used by cross-examining attorneys to attempt to elicit testimony favorable to their view of the case. They can also be used to box an expert in ways that undermine the credibility of his or her testimony. For me, the key to dealing with hypothetical questions begins with fully understanding the assumptions that are being made. When an attorney poses a hypothetical question to me, I write down the assumptions to ensure I fully understand them and think about their nuances. And then, I carefully consider the questions asked in light of the assumed facts. When a cross-examining attorney asks you a hypothetical question or series of hypothetical questions, he or she is not trying to help you. So insure that you fully understand any hypothetical assumptions and answer them with care. Not all hypothetical questions are good ones.  I was recently asked a hypothetical question in an arbitration. Despite three attempts on the part of the attorney, I said each time that I simply could not understand the hypothetical. Fortunately, the arbitrator agreed with me and he moved on to another topic.
  10. Video depositions.  When video depositions are taken, it is a good idea to dress well, keep a clean work area in front of you, and try to watch the camera, or at least the area of the camera as much as possible.  If you shouldn’t spar with opposing counsel in an oral examination, that rule is even more important in a video deposition. Remember, the only participant being recorded on video is the expert. The counsel who is baiting you will not appear. I try to follow the same rule of waiting to formulate an answer in video depositions. While the pause will show up, bad speech mannerisms will trump a short pause for thinking every time if the video sees the light of day at trial.  Keep in mind that one of the key reasons to take a video deposition is to capture sound-bites that can be used to impeach an expert at trial. Years ago in a valuation-related trial I participated in, one expert was devastated by the use of a video deposition.  He testified confidently about one line of questioning at trial. The cross-examining attorney then asked him, “Are you sure about your testimony?”  The expert’s response was, “Yes.” The attorney then asked that a certain video clip be played from the expert’s deposition.  In that short clip, he testified just as confidently that a different position was correct. The attorney didn’t even have to ask the question, “Were you lying then or are you lying now?”  It didn’t matter.  The damage was done and the expert lost credibility with the trier of fact. While video clips don’t seem to be played very often in business cases, at least based on my experience, experts need to exercise care to give the best video depositions possible in case one is used in a matter in which she is involved.

So there we have it – 10 ideas for giving effective expert depositions.  I hope you found the information helpful.  If you have other ideas, please comment below or share them with me privately.

Be well,



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