Trial Magazine
Feature Article
Witness Impeachment 101
Exposing inconsistencies in a witness’s testimony during deposition and trial is a seemingly simple but crucial process you must get right.
May 2023The credibility of witnesses’ opinions and statements can be key to proving, or disproving, a party’s case. In some instances, attacking an opposing witness’s credibility through prior inconsistent statements is more than just helpful to your case—it’s part of your duty to advocate vigorously for your client.
In my experience, the most impactful way to discredit witnesses is to impeach them with prior inconsistent testimony in front of the jury.1 This can be done with expert witnesses and lay witnesses alike. When done correctly, the witness’s opinions and testimony will be undermined—they will appear either dishonest or as though they have an incomplete grasp of material case facts and their own opinions.
To set yourself up for success, start preparing at the deposition, know the proper steps for impeaching a witness, and understand the factors to consider when you have the chance to do so, either at deposition or at trial.
Set the Foundation With Detailed Depositions
When a witness is impeached with prior inconsistent testimony, depositions almost always will be the comparative evidence. Therefore, deposition testimony must be extracted carefully. When dealing with an expert witness, for example, there may not be a written report to start from.
Generally, there is a split between states: some follow Federal Rule of Civil Procedure 26(a)(2)(B), requiring written expert reports, while in other states, a written report is optional.2 Because expert reports are signed by the witness, these reports can be used against an expert if there is an inconsistency during deposition or trial testimony related to the report. In states that do not have the requirement, depositions are the first opportunity to gather an expert’s opinions and lay the foundation for future impeachment.
At deposition, question the witness with the foresight of potentially using the answers for impeachment at trial.
At a minimum, ask concise questions during an expert’s deposition. Stay away from long, multi-part questions. This cuts down on the need to dissect long answers and often saves you from objections. Question the witness with the foresight of potentially using the answers for impeachment at trial. And expect any answer to a question related to a central issue in your case to be contradicted at trial.
Consider the transcript excerpts below from a recent birth injury case. In this case, the plaintiff alleged that the defendant doctor pharmacologically prolonged her labor and refused to perform an emergency C-section, resulting in the baby’s shoulder dystocia, hypoxia, and other birth injuries. Here, my co-counsel3 asked the deponent, the defendant doctor, a simple question. His answer would later be used against him at trial.
Q. Would it have been within the standard of care to change [Plaintiff]’s care plan from an anticipated vaginal delivery to a C-section prior to 2:50 p.m.?
A. No, there’s no standard of care.
Q. Do you understand what the standard of care means?
A. With obstetrics there’s no standard of care when it comes to labor and delivery and that. There’s no standard of care saying whether this patient should have been vaginal or C-section, and this labor fulfilled what is an acceptable way of following a labor on a patient toward delivery.
The deponent was asked a concise question related to liability and was pressed on his understanding of the term “standard of care.” My co-counsel was not expecting the deponent to say there is no standard of care for labor and delivery, but she had the foresight to ask focused and concise questions to preserve her ability to impeach him later.
How to Properly Impeach
Successful impeachment relies on following these key steps:
- recognize when a witness makes an inconsistent statement
- lay the foundation for the prior statement
- confront the witness with the prior statement
- use your persuasion skills to highlight the inconsistencies for the jurors.4
Preparation for impeachment opportunities coincides with trial preparation generally. It’s good practice to review all depositions and build charts for each witness to separate out their opinions on relevant issues with citations to the relevant portions of their deposition. Most jurisdictions do not allow impeachment on immaterial or irrelevant issues, so having all of the key, relevant opinions noted in a chart will narrow your focus during direct examination.5
If a witness says something on the stand that you believe is impeachable, first determine whether the statement or opinion truly is inconsistent with prior testimony under the standard in your jurisdiction. The majority view finds an inconsistency to be a “material variance” when the pretrial testimony “bend[s] in a different direction” from the trial testimony.6
Further, courts look to the overall effect the inconsistency has on the witness’s testimony, finding that “inconsistency is not limited to diametrically opposed answers”7 and that it is enough if the “proffered testimony, taken as a whole . . . affords some indication that the fact was different from the testimony of the witness whom it sought to contradict.”8
So when opposing counsel objects to an impeachment attempt, focus on the overall effect of the inconsistency and argue that it has not only bent in a different direction from the pretrial testimony, but it has shifted the impression of the statement.
Returning to the earlier birth injury example, the defendant doctor’s deposition testimony and trial testimony during direct examination had clear inconsistencies:
Q. And you provided reasonable and appropriate care, you believe?
A. Yes.
Q. And met the standard of care?
A. Yes.
This witness’s direct examination testimony is a complete reversal of his pretrial deposition testimony about the standard of care, thus meeting the degree of inconsistency required for impeachment. Further, the testimony is sufficiently material to the case, because this statement is about the standard of care.
Next, properly impeach the witness. All states require a similar process wherein a foundation is laid and the witness is confronted. State rules vary, with some requiring witnesses or their counsel be given a copy of their testimony or that the witness be afforded an opportunity to explain the inconsistency—or both.9 Regardless of your state’s rule, provide the witness with a copy of their testimony. You do not want to look as though the words you are reciting are from anyone other than the witness on the stand. I also like to project the testimony on the wall or screen so the jurors can read along.
Consider whether to allow the witness to explain their answer on a case-by-case basis, taking into account that person’s skill at testifying. Be careful not to give away any of the ground you just gained by letting the witness “explain away” the inconsistency.
When conducting cross-examination, in addition to walking a copy of the transcript up to the witness, have copies of the deposition to give to the judge and opposing counsel. Confirm that what was said on direct examination contradicts the testimony given in pretrial proceedings. For example:
Q. The last thing you said is that you did not violate the standard of care, correct?
A. Correct.
Q. Is there a standard of care, Doctor, when it comes to labor and delivery?
A. Yes.
Once the witness has committed themself to this testimony twice before the jury—depending on the jurisdiction—show the witness a physical version of their deposition or other testimony that contains the inconsistency. Next, walk the witness through the testimony to confirm whether they agree or disagree with having made that statement. If the witness agrees, you may examine further and, depending on the jurisdiction, provide the witness with an opportunity to explain the inconsistency.
If the witness disagrees, introduce extrinsic evidence, which is evidence from an outside source—such as another witness who heard the inconsistent comment, a transcript of prior proceedings, or an audio tape of the comment—to support the impeachment attempt.10
The following example shows that the witness was provided a copy of his deposition, allowed to confirm whether he stated what is written, and given an opportunity to explain the inconsistency to the jury:
Q. Doctor, I’m going to hand you a copy of your deposition. If you could please turn to page 128 of that deposition. Let me know when you are there.
A. Yes, ma’am.
Q. Doctor, the question that I just asked you, would it have been within the standard of care to change [Plaintiff]’s care plan from an anticipated vaginal delivery to a C-section prior to 2:50 p.m. Did you review your answer in your deposition?
A. Yes, ma’am.
Q. Your answer was no. There’s no standard of care. And I asked if you understood what the standard of care is. Do you understand what the standard of care is, Doctor?
A. Yes.
Q. Okay. And what is that?
A. It’s what a reasonable physician would do in an instance.
Q. Doctor, I asked, do you understand what the standard of care is? And you stated, with obstetrics there is no standard of care when it comes to labor and delivery in that there is no standard of care saying whether this patient should have been vaginal or C-section, and this labor fulfilled what is acceptable. At that time, you told me that there is no standard of care for labor and delivery, did you not?
A. The words were what you said.
Q. Can I trust your testimony that what you said to me under oath in your deposition is what you believed when you were taking care of [Plaintiff]?
A. I was thinking there was no single standard of care, and there are several standards of care.
Once the impeachment process is complete through these steps, use your persuasion skills during examination and closing argument to further erode the witness’s credibility. This is a situational exercise, so be wary of pushing a witness too far—the goal is to discredit the witness in front of the jury, not be a bully. The impeachment of the witness in the birth injury case concluded as follows:
Q. Doctor, if there’s no standard of care, you can’t be held accountable for the decisions that you’ve made in managing [Plaintiff]’s labor, correct?
A. Correct.
Q. And if there’s no standard of care, you can’t be negligent in how you manage a patient through labor and delivery. Do you understand that?
A. Yes, ma’am.
In closing argument, a discrepancy in the witness’s testimony like this could be highlighted for the jurors to show how incongruent—and unbelievable—it is for a doctor to state that they could not be accountable for actions that harmed a patient in their care.
When to Impeach—Depo or Trial?
There is no guarantee that witnesses will contradict themselves in a future deposition or at trial. However, it is possible for this to occur with the same witness in a different case. For example, if the same deponent above was called for a deposition in a different matter, even outside of our office, and stated that there is a strict standard of care for labor and delivery, the testimony above could be used for impeachment—but only if the attorney deposing the witness holds the transcript. This is why information sharing among plaintiff attorneys about expert witnesses can help keep deponents honest and their opinions standardized.
It is possible that your witness has been deposed previously in a similar case and their deposition could be available to you. If you find yourself in this position, when is the right time to impeach the witness? A prime scenario would be when the witness previously testified about specific causation in a different case that is substantially similar to yours. You have the transcript, and during the deposition, the witness gives an opinion inconsistent with the opinion provided in the previous deposition. Whether to discredit the witness on cross or hold this information for trial requires a strategic decision about when you can make the largest impact by exposing the inconsistency.
If you know a witness giving impeachable testimony will not appear at trial, or if it is unknown whether that witness will appear, impeaching during the deposition may send a direct message of strength to the other side—and also be read to or played for jurors if the case proceeds to trial. If their witness will not hold up well at trial, it could influence settlement negotiations in favor of your client. Alternatively, saving impeachment for trial can also tilt the jury in your favor and tarnish the witness’s credibility without providing opposing counsel sufficient time for damage control.
Each part of the impeachment process requires critical thinking and consideration of your client’s best interests. Initially asking concise, focused questions in the deposition sets you up with a usable record to present to the witness at trial. At trial, pay careful attention to the witness’s direct examination—with the help of your testimony chart, you will easily spot inconsistencies that are ripe for impeachment and undermine the witness’s credibility in front of jurors.
Amy Collignon Gunn is an attorney at The Simon Law Firm in St. Louis, Mo., and can be reached at agunn@simonlawpc.com. The author thanks Tyler H. Shah, her law clerk, for his contributions to this article.
Notes
- See Fed. R. Evid. 613. Witnesses also can be impeached through other methods, such as to reveal bias. For more on impeaching witnesses, see Fed. R. Evid. 607–610.
- See, e.g., Mo. Sup. Ct. R. 56.01(b)(6)(B); N.C. Gen. Stat. §1A-1, R. 26(b)(4)(a)(2); Pa. R. Civ. P. 4003.5(a)(1); Tenn. R. Civ. P. 26.02(4) (written expert reports not expressly required); but see Ohio R. Civ. P. 26(B)(7)(b)-(c); Utah R. Civ. P. 26(a)(4)(A)-(B); Wyo. R. Civ. P. 26(2)(A)-(B) (written expert reports required).
- The transcript excerpts used throughout this article are from a birth injury case I tried with my colleague Erica B. Slater.
- See, e.g., Douglas J. Stamm, Back to Basics: Impeachment by Prior Inconsistent Statement, 36 Or. State Bar Litig. J. 1 (Spring 2017), https://jhoffman.com/wp-content/uploads/2017/08/Back-to-Basics-Impeachment-by-Prior-Inconsistent-Statements-Spring-2017.pdf.
- See State v. Frommelt, 159 N.W.2d 532, 535 (Iowa 1968) (“It is generally held a witness may be impeached by showing his testimony upon a material matter is inconsistent with a prior statement made by him.”); Racky v. Belfor USA Grp., Inc., 83 N.E.3d 440, 463 (Ill. App. Ct. 2017) (citing Goldstein v. Hertz Corp., 305 N.E.2d 617 (Ill. App. Ct. 1973)); Aliff v. Cody, 26 S.W.3d 309, 318 (Mo. Ct. App. 2000) (citing Lineberry v. Shull, 695 S.W.2d 132, 136 (Mo. Ct. App. 1985)).
- See 1 Robert P. Mosteller et al., McCormick On Evidence §34 (8th ed., West 2022); see also United States v. Stewart, 907 F.3d 677, 687 (2d Cir. 2018).
- United States v. Matlock, 109 F.3d 1313, 1319 (8th Cir. 1997) (citing United States v. Russell, 712 F.2d 1256, 1258 (8th Cir. 1983) (per curiam)).
- United States v. Gravely, 840 F.2d 1156, 1163 (4th Cir. 1988) (quoting United States v. Barrett, 539 F.2d 244, 254 (1st Cir. 1976)).
- See, e.g., Cal. Evid. Code §770 (West 2022) (“extrinsic evidence of a statement made by a witness that is inconsistent with any part of his testimony witness . . . shall be excluded unless” the witness was given “an opportunity to explain or to deny the statement”); Colo. Rev. Stat. Ann. R. 613 (West 2023) (“Before a witness may be examined for impeachment by prior inconsistent statement the examiner must call the attention of the witness to the particular time and occasion when, the place where, and the person to whom he made the statement. . . . The exact language of the prior statement may be given.”); Ind. R. Evid. 613 (West 2023) (“When examining a witness about the witness’s prior statement, a party need not show it or disclose its content to the witness. But the party must, on request, show it or disclose its contents to an adverse party’s attorney.”).
- See People v. Jenkins, 537 N.W.2d 828, 832 (Mich. 1995) (“The purpose of extrinsic impeachment evidence is to prove that a witness made a prior inconsistent statement—not to prove the contents of the statement.”); Litton v. Kornbrust, 85 S.W.3d 110, 114 (Mo. Ct. App. 2002) (“In the context of impeaching a witness with extrinsic evidence of a prior inconsistent statement, ‘extrinsic evidence’ means evidence of the prior inconsistent statement ‘offered other than through the witness himself’ (i.e. another witness that heard the inconsistent comment, a transcript of prior proceedings, an audio tape of the comment, etc.)” (citing State v. Foster, 854 S.W.2d 1, 8 (Mo. Ct. App. 1993)).
