By James J. Mangraviti, Jr., Esq.
A common way to challenge the credibility of an expert witness in through impeachment with the expert’s prior inconsistent statements. Common sources to impeach an expert witness are the expert’s publications, their prior testimony, and their prior expert witness reports. Below are sample expert witness deposition impeachment questions, where the prior statement was from a prior report.
Example: Expert Witness Deposition Impeachment Questions
Q: Can you identify what Exhibit 73 is for me?
A: Yes. That’s a report I wrote October 24, 2005, in the Lantz, L-a-n-t-z, versus Smith and Collins case to Mr. Leonard Welles in Bellefonte, Pennsylvania.
Q: And is that a case that Mr. Chester is involved in?
A: Yes. He deposed me in that case.
Q: Right. And can you just briefly tell me what the facts of the case were?
A: In that particular case, Laurel Lantz, on page 3, is actually what I talk about here, suffered a torn anterior cruciate ligament in her right knee and other tears when she fell through the springs on a trampoline, a backyard trampoline in the Smith home in May of 2002.
She was on the trampoline with other people. She jumped a few times. She decided to get off, was making her way across the trampoline, away from the center. She was planning on sitting down. She asked the other kids to stop but they didn’t stop bouncing. She felt herself go off balance. She tried to get off the trampoline. One leg fell through the springs, the other leg on the mat, and then when she tried to get her leg out over the rail, that’s when she fell and got seriously injured.
Q: Okay. Now, in that particular case and in this report, Exhibit 73, did you make a recommendation as to whether or not this particular trampoline should have had an enclosure?
A: I think I did.
Q: Okay. And do you recall that without reading the report?
A: I think if there was an enclosure there set up, she wouldn’t have fell through the springs at the time because that’s the purpose of the enclosure, to keep you on the trampoline.
Q: Well, do you recall in the report referring to the enclosure that you were recommending as a safety enclosure?
A: Don’t know. I might have.
Q: Okay. Let’s take a look at page 7.
A: Sure.
Q: At the very bottom. The trampoline—I’ll read this. “The trampoline was further defective and negligently designed in that it was not sold as a single unit with safety enclosures that would prevent jumpers from being thrown off of the jumping surface either onto the ground or through the springs.”
A: That’s correct. I used the words “safety enclosures.” I probably shouldn’t have. That’s correct.
Q: Going on to page 8, the next sentence following the one I just read in the record. You go on to say, “These safety cages have been manufactured and sold as separate units since at least the mid-1990s and could readily be utilized with the trampoline so that the likelihood of injury on these devices could at least be reduced.” Did you write that?
A: Yes, that’s correct.
Q: And you used the term “safety cages”?
A: Right. I didn’t call the product a safety cage. I used a term.
Q: Safety cage?
A: Right.
Q: Is that a term that you use frequently?
A: I don’t usually do that. I think when I was—and again, I can’t remember when I wrote this report. I wasn’t calling it—titling it a safety cage. I called them enclosures. In this particular case, what I was trying to say is that had she—had this enclosure been there, this kind of accident, would have saved it. It would have been safer for her to get out of the trampoline. And I think that’s why I used “safety cages.” Not as a title of the cage, because I used the word “cage” also here rather than “enclosure.” It was just a term I used in the report.
Q: So it’s quite possible that someone even as experienced as you might refer—
A: I used it again, by the way, on the bottom too.
Q: —might refer to an enclosure as a safety enclosure, okay, inadvertently even though the product may not be called a safety enclosure in terms of its formal name. Is that a fair statement?
A: Probably some people can call it a safety enclosure, sure.
Q: Now, if somebody informally referred to this on a regular basis as a safety enclosure, would the use of that term by that individual lead them to believe that the warnings on the trampoline bed were voided?
Mr. Lester: Objection to foundation.
A: I don’t know.
Mr. Fiore: Well, do you have an opinion on that?
A: No. I’ve never been asked that question. I don’t know if somebody inadvertently used any term, what that would mean in relationship to the warnings. I don’t know how to answer that.
Q: Okay, so in terms of your opinion in this case, it is highly significant that the term “safety enclosure” is the name of the product as opposed to a term with which the user refers to the enclosure?
A: Right, that’s my opinion. There’s a big difference.
If counsel can establish that an expert tailors his/her opinions depending on who retains them, that will severely undercut the expert’s credibility. An effective way to do so is to impeach the expert with prior inconsistent statements from past cases – as was attempted above.
James J. Mangraviti, Jr., Esq., has trained thousands of expert witnesses through seminars, conferences, corporate training, training for professional societies, and training for governmental agencies including the FBI, IRS, SEC, NYPD, Secret Service, and Department of Defense. He is also frequently called by experts, their employers, and retaining counsel to train and prepare individual expert witnesses for upcoming testimony. Mr. Mangraviti assists expert witnesses one-on-one with report writing, mentoring, and practice development. He is a former litigator who currently serves as Principal of the expert witness training company SEAK, Inc. (www.testifyingtraining.com). Mr. Mangraviti received his BA degree in mathematics summa cum laude from Boston College and his JD degree cum laude from Boston College Law School. Mr. Mangraviti has designed dozens of expert witness training programs and has personally taught experts in a group setting over 250 times since 1997. He is the co-author of thirty books.
