What Makes a Good Expert Witness


When you're looking for an expert witness, you want to find a witness who has the credentials and expertise to be credible to the judge, jury, and opposing counsel. You also want an expert who will be able to clearly communicate opinions to the finder of fact, and who can make complex technical subjects and jargon understandable to people who may have little or no prior exposure to the expert's area of expertise or its terminology.

Although many factors play into an expert's effectiveness, and the factors relevant to a particular expert or case may turn on the type of case and its facts, by following some basic principles you can be reasonably confident that your expert will be effective.

What Makes an Expert Witness Good

When we speak of a good expert witness, we mean a lot more than "the witness is very knowlegeable" or "the witness rarely makes mistakes while testifying". We are referring to the expert's ability to impress upon the judge and jury that he's qualified and competent, to speak authoritatively and persuasively, to make complex issues understandable, to anticipate and diminish the impact of the opposing party's case, and to avoid any impression of arrogance or haughtiness.

In some fields that can be a tall order. Sometimes the most qualified individuals in a field of study are bookish or antisocial, such that you must choose between struggling to find a highly qualified expert who has already developed skills as a witness, or spend a considerable amount of time and energy preparing your witness for trial without the assurance that your efforts will be effective. What factors should you look for that can help you narrow your search?

  • Competence - Your expert should have credentials that make it clear that he is qualified to testify on the issues relevant to your case, and should also have experience within the field demonstrating real world accomplishments that match those credentials. Credentials can be exaggerated or embellished, but it's a lot harder to fake experience.

  • Appearance - Appearance isn't everything, but it is important. You want an expert who will present well in court, and who won't conflict with a jury's conception of how the expert should appear. Even if the expert comes from a field in which every day is casual Friday, when the expert comes to court he needs to dress and look the part.

  • Articulate - Your expert should be well-spoken, engaging and confident. You need to find an expert who can communicate effectively with laypersons. If these skills do not come naturally to your preferred expert, be careful -- it is highly unlikely that an expert who seems hesitant, arrogant, disengaged, unfocused, or who gives complicated, jargon-laded answers is going to learn to communicate more effectively by the time of a deposition or trial.

  • Familiar With Legal Proceedings - A few people seem to be natural experts, quickly grasping the principles of giving effective testimony, the rules of evidence and how they relate to reports, evidence and testimony, and the differences between a deposition and trial and how questions and answers are likely to differ depending on the context. However, for most people it's a long and difficult learning process. Be careful to select an expert who has the necessary background to be effective at all stages of your case, and who will be able to tolerate the pressure -- and even the boredom -- that can be associated with depositions and trials.

  • A Good Listener - Your expert needs to understand that it is important to listen to the question being asked, and to answer that question. If your expert digresses into long narratives or war stories at every opportunity, exercise caution. Ask the type of question that is likely to come up at deposition or trial, and have your expert answer those questions in the manner that they would use within each context.

  • Expertise as a Teacher and Presenter - It's not crucial that your expert have experience teaching or giving presentations, but an expert who has experience relating concepts to a less knowledgeable or lay audience is more likely to be able to do the same thing when testifying before a jury. No matter what your expert's experience, you should make sure that your expert is able to explain technical issues and industry jargon in a manner that a layperson can understand.

How to Help Your Expert Be More Effective

No matter how experienced an expert may be, there's always room for some polish. But if your expert is less experienced it's important to make sure that you educate your expert on how to give effective testimony, and that you practice with your expert to the point that you're comfortable that his deposition and courtroom performance will be effective.

  1. Presentation and Posture - Although it may seem obvious, an inexperienced expert may need to be cautioned about posture and fidgeting, the importance of sitting up straight and not making distracting movements.

  2. Connecting With the Finder of Fact - A less experienced witness tends to present testimony to the person who is asking questions, usually the attorney who is examining or cross-examining the witness. Make sure that your expert understands when and how to direct testimony to the finder of fact, when to make eye contact with the jury, what facial expressions to display. Even a simple smile and a nod many not show up on the transcript, but can mean a lot in person.

  3. Giving Clear Answers to Questions - Your expert should know the importance of clarity, and also of conciseness. Your expert should answer the question that is asked, then wait for the next question. As a lawyer you know the power of the pause, how you can draw additional testimony from a witness after you get your initial answer by letting the seconds tick by. Your expert should know not to fall for that trick.

  4. No Guessing - Your expert should know that his answers to a question should be based upon his knowledge, not guesswork. If he's asked to hypothesize, it should be clear that he's addressing a hypothetical situation and not the established facts.

  5. A Calm and Cool Demeanor - Your expert needs to know the importance of keeping his cool during testimony. Testimony or facial expressions that show anger or contempt will undermine his credibility.

  6. The Basics of the Opposing Party's Strategy - Make sure that your expert understands the tools and tricks that opposing counsel will use to try to undermine his credibility, and perhaps to antagonize or anger him during cross-examination. Your expert needs to know that it's okay to ask for an unclear question to be clarified, and how to avoid common traps opposing counsel may attempt to lay.

Copyright © 2014 Aaron Larson, All rights reserved. No portion of this article may be reproduced without the express written permission of the copyright holder. If you use a quotation, excerpt or paraphrase of this article, except as otherwise authorized in writing by the author of the article you must cite this article as a source for your work and include a link back to the original article from any online materials that incorporate or are derived from the content of this article.

This article was last reviewed or amended on Dec 16, 2016.