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The Three Ps of Expert Depositions: Planning, Preparation, and Personality

Renee Miller-Mizia and Elaine Wood


  • Experts and counsel should collaborate early to define the engagement's scope, ensuring facts are accurate and all documents are reviewed.
  • Experts need to articulate the facts, assumptions, and methodologies behind their opinions, thoroughly review all expert reports, and familiarize themselves with frequently and infrequently cited documents.
  • Effective experts and counsel need excellent listening skills, patience, humility, and confidence, and should answer questions clearly and accurately, request clarifications as needed, and remain composed and focused throughout the deposition.
  • The effectiveness of expert witnesses at depositions is a result of innate abilities, learned skills, and practice, encompassing detailed planning, thorough preparation, and a balanced personality approach.
The Three Ps of Expert Depositions: Planning, Preparation, and Personality
Peter Cade via Getty Images

“The most effective expert witnesses are skilled raconteurs who explain their opinions and analyses in simple terms that are easily understood and comprehensible. Sometimes they even make us laugh. But what influences the effective expert’s ability to come across so well during a deposition? Are the expert’s skills innate, learned, or practiced?

This article gathers information from experienced expert witnesses about the factors that can maximize the effectiveness of expert testimony. As you will see, advance planning and preparation can influence effectiveness. And, while an expert’s personality is an inherent factor, being aware of certain aspects of expert demeanor can enhance the effectiveness of the expert’s testimony. We have summed up these factors as the “three Ps”: planning, preparation, and personality.


  • Counsel and experts should work together in the early stages of the expert’s engagement to define its scope. This is especially important in matters where multiple experts are involved.

  • Get the facts straight. Check and double check each fact before relying on it. When possible and where appropriate, find corroborating sources for a fact. If “things don’t add up” when the full set of facts is taken together, ask why not as soon as possible in the engagement. Don’t lose sight of the big picture.

  • Experts should check in with counsel early and often with any questions about documents received, missing documents, the completeness of the production, or anything that seems inconsistent with the information reviewed.

  • Counsel and the expert should meet in advance of the expert’s deposition. Review the types of questions likely to be asked, discuss the styles of the lawyers expected to handle the deposition, and review the standards for work product, drafts, and privileged communications. Discuss the current status of the pleadings and litigation.

  • Confirm that the expert’s CV is accurate and includes recent updates and new information.


  • Make sure the expert is able to provide key facts and assumptions for each of his or her opinions. The expert must also be prepared to explain the methodology he or she employed and identify the documents relied on in forming his or her expert opinions.

  • Before the deposition, both expert and counsel should thoughtfully review all written expert reports (including from your opponent) pertaining to the testifying expert’s analysis.

  • An expert report may include hundreds of footnotes. Take a step back and look at the documents most often referenced. Also look at those infrequently cited. It is important to be familiar with both types.

  • Have dinner and get a good night’s rest the evening before the deposition. Dress professionally, but comfortably, for what may be a long day ahead.


The following tips are directed specifically to experts, but attorneys should heed them as well when they prepare experts for deposition.

  • Listening skills are essential for an expert witness (as well as counsel), particularly during a deposition. Listen and be sure you understand the question. It is fine to respond that you don’t understand the question and ask for it to be rephrased. “I don’t know” is an acceptable answer, too. So is conveying that the question is outside the scope of your analysis.

  • Patience is a virtue in effective expert witnesses. Take your time in answering questions. While you should avoid excessively long pauses, do pause before answering. This gives your attorney time to object, and you time to think about the question.

  • A bit of humility also contributes to effective testimony. Although many experts are outstanding teachers, a deposition is neither the place nor the time for extended, lengthy, complicated explanations. Answer only the question that was asked. Be cautious of compound questions. Ask the deposing attorney to separate each question, and then answer them individually. Don’t interrupt or talk over the attorney.

  • Witnesses don’t need to be perfect, and effective experts are comfortable with this. Although a strong command of the facts is expected, a photographic memory is not. Answer as accurately as you can, and if you need to see your own report, or a document on which you relied to refresh your recollection, ask for it. It also is acceptable to return to an earlier question if you remember more details or want to clarify a previous answer.

  • It is okay to be human and to make certain requests, such as to take a break or for a fresh glass of water. You may ask when lunch is scheduled, or at what time the day is expected to conclude. Your goal is to be focused and composed. Sometimes getting up to take a short walk can help you maintain a clear mind.

  • Confidence is an important quality for expert witnesses. You believed in your opinion when you wrote it in the cool light of day, so keep believing it when you are under fire. Nothing has changed other than the setting. You are the expert. These are your opinions and your report. Be confident but not arrogant.

The answer to our earlier question—are the expert’s skills innate, learned, or practiced?—is “all of the above.” At deposition, effective expert witnesses employ a mix of the three Ps: planning, preparation, and personality.