Direct Examination of Expert Witnesses: A 7-Step Guide

While the same basic principles of direct examination apply to all witnesses, direct examination of an expert poses additional challenges – namely, the need for the jury to understand the scientific facts behind the expert’s reasoning and to take your expert more seriously than they take the other expert. Here’s how to introduce your expert,

Cross Examining Expert Witnesses

ByAnjelica Cappellino, J.D.

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Published on December 21, 2017

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Updated onJune 23, 2020

Cross Examining Expert Witnesses

While the same basic principles of direct examination apply to all witnesses, direct examination of an expert poses additional challenges – namely, the need for the jury to understand the scientific facts behind the expert’s reasoning and to take your expert more seriously than they take the other expert.

Here’s how to introduce your expert, put their qualifications and testimony in context for the jury, and present them as the expert to take seriously.

Step 1: Choose your expert carefully.

A well-chosen expert witness makes direct examination easier. It’s best to start the expert selection process as soon as you realize the case may demand an expert’s testimony. Never skimp on preparing an expert witness: No matter how many cases your expert has testified in before, only thorough preparation will make them ready to testify in your current case.

Step 2: Plan to teach.

Most attorneys are comfortable as advocates; fewer have teaching experience. To ensure the jury understands your expert’s approach, reasoning, and conclusions, however, you and the expert will need to team up to teach the jury some essential facts. Identify points at which “teaching tools” like visual aids will help the jury understand key points, and use these tools.

Step 3: Get an introduction.

The first thing to ask your expert witness is for the witness to introduce himself or herself to the jury. Since you’ve prepared your expert for this moment, he or she will be ready to provide a strong foundation on which you can establish their qualifications.

Step 4: Tell ‘em what you’re about to tell ‘em.

All good trial advocates regularly use the well-worn essay format: “Tell ‘em what you’re about to tell ‘em, then tell ‘em, then tell ‘em what you just told ‘em.” During direct examination of an expert, do this by asking, after the introduction, “Doctor [Professsor], are you here today to testify that….” When your expert says “yes,” follow up with, “Thank you, Doctor, but before we get to that I’d like to ask you about your qualifications….”

Step 5: Get your expert’s qualifications.

This portion of cross-examination should do double duty: You’ll need to show the judge that the witness has the necessary qualifications to be certified as an expert, and you’ll also need to provide a foundation for the jury to connect the expert’s areas of expertise to the facts of the case.

Start by focusing on the expert’s most relevant education, work background, training, or other credentials. Then, use supporting qualifications to round out the picture. In some cases, asking a conversational question that leads to a short anecdote or a mention of the expert’s hobbies can help the jury find your expert more relatable: The expert looks more like a trustworthy person and less like a walking textbook.

If your expert has any potential credibility weaknesses, address them here. Doing so makes you both read as more honest and relatable to the jury, and it makes opposing counsel’s raising of these weaknesses on cross-examination less impressive.

For instance, to forestall questions about “fees bias” on cross-examination, ask your expert a brief question about the time and effort they spent preparing on the case. When opposing counsel brings up fees on cross, those fees will look reasonable, as the jury already knows the witness has done some hard work to earn them.

Establish the scope of your expert’s qualifications to thoroughly cover the issues you want the expert to address, but stay within this scope throughout direct examination. Doing so not only reduces the risk of a challenge based on the rules of evidence, it also helps convince the jury that your expert absolutely knows what he or she is talking about.

Step 6: Plan the rest of your direct examination.

Once you get into the “meat” of direct examination, you’ll be covering points like the expert’s opinion, the basis for that opinion, the sources of information the expert used, and where and why the expert differs from the other side on the facts and their opinion. Depending on the particular strengths or weaknesses of your case, you may need to rearrange these topics.

Throughout direct examination, preface each change in topic with a clear verbal “guidepost”: “Let’s talk about the sources you consulted….” These guideposts help orient the jury and judge. Stick to clear, plain language whenever you can to help avoid confusing jurors and ensure that technical terms stay clear and organized.

Finally, during direct examination, always address your expert by his or her title: “Doctor, would you tell us….” “Professor, would you explain….” Position yourself as a student who respects your witness’s expertise and is present to learn, and the jury will do so as well.

Step 7: Tell ‘em again.

End direct examination of an expert witness by positioning your expert witness to summarize their conclusions – and to do so in a way that mirrors the theory of the case you’ve already presented to the jury in your opening statement. By doing so, you give the jury a “takeaway” that reinforces your expert’s credibility, ties their opinions in with your theory of the case, and helps the jury connect the facts to that theory.

About the author

Anjelica Cappellino, J.D.

Anjelica Cappellino, J.D.

Anjelica Cappellino, Esq., a New York Law School alumna and psychology graduate from St. John’s University, is an accomplished attorney at Meringolo & Associates, P.C. She specializes in federal criminal defense and civil litigation, with significant experience in high-profile cases across New York’s Southern and Eastern Districts. Her notable work includes involvement in complex cases such as United States v. Joseph Merlino, related to racketeering, and U.S. v. Jimmy Cournoyer, concerning drug trafficking and criminal enterprise.

Ms. Cappellino has effectively represented clients in sentencing preparations, often achieving reduced sentences. She has also actively participated in federal civil litigation, showcasing her diverse legal skill set. Her co-authored article in the Albany Law Review on the Federal Sentencing Guidelines underscores her deep understanding of federal sentencing and its legal nuances. Cappellino's expertise in both trial and litigation marks her as a proficient attorney in federal criminal and civil law.

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