Requirements for Witness Testimony in Federal Court

picture of the outside of a federal courthouse

What does it take to be a witness in a lawsuit in federal court? Mostly, it takes being in the right place at the right time (or the wrong place at the wrong time, depending on your perspective). Article VI of the Federal Rules of Evidence contains formal requirements for witness testimony in federal court, though some rules from other parts of the FRE also apply. Below are five of those rules.

1. Competency – Rule 601
This is a blanket rule that everyone is competent to be a witness, unless the rules elsewhere say differently. In certain circumstances, a party to a lawsuit can ask the court to determine whether someone is in fact competent to testify. For example, a child might be too young to tell the difference between what is true and what is false. The court can hold a hearing to determine whether the witness is competent.

2. Oath or Affirmation – Rule 603
Before a witness can testify in court, the witness must give an oath (“I swear”) or affirmation (“I affirm”) that he or she will testify truthfully. No particular form is required. For instance, it’s no longer necessary that a witness swear on a Bible. Instead, the oath or affirmation suffices so long as it “impresses” the duty to testify truthfully “on the witness’s conscience.”

3. Relevance of Testimony – Rule 402
For all evidence, including witness testimony, This rule requires that the evidence be relevant to the case. Rule 401 says that evidence is relevant if it “has any tendency” to prove or disprove a fact that is “of consequence in determining the action.” As an example of irrelevant evidence, what kind of coffee the witness drank on the day of trial is not relevant. It does have a tendency to prove a fact—what coffee the witness drank—but that fact is not “of consequence” in the lawsuit. It makes no difference to the outcome of the lawsuit what the witness did or did not drink that morning.

4. Personal Knowledge – Rule 602
In general, a witness can only testify to facts about which the witness has personal knowledge. Roughly, personal knowledge means something that the witness him- or herself perceived, not something he or she heard from somebody else. In fact, before the witness can even testify, there must be evidence showing that the witness has personal knowledge of the facts about which he or she will testify. A witness first must show how he or she knows something before being allowed to show what he or she knows. This can be done through preliminary questioning of the witness. For example, an attorney might ask, “Did you hear what Mr. Defendant said to Mr. Plaintiff?” If the witness answers in the affirmative, then the lawyer can ask what it was the defendant said to the plaintiff.

5. No Opinions – Rule 701
Normally, witnesses are called to testify about facts. The goal is to help the jury understand the facts involved in the case, not to help the jury understand how witnesses feel about the case. But there are some exceptions that allow for opinion testimony. First, a lay witness (i.e., not an expert witness) can give an opinion if the opinion is based on the witness’s perception, helpful to determine a controverted fact in the case, and not based on specialized knowledge (like scientific or technical expertise). Second, witnesses who qualify as experts can provide opinion testimony. For instance, an accident-reconstruction expert might provide his opinion for how fast two cars were traveling when they collided. In that case, the expert is offering an opinion based on his or her expertise.

In conclusion, whether you think you were in the right place at the right time or the wrong place at the wrong time, you’re only allowed to testify in a federal lawsuit if you meet the above requirements. Luckily, you won’t have to remember these on your own. If a lawyer wants to call you as a witness, he or she will be sure you’re prepared to take the stand.

What do you think about all of this? Here at The Bail Pros, we do what we can to educate people on every aspect of the legal system. We want to make sure that everyone is informed in case one of these difficult situations ever arises. If you have any questions or comments, or would like some more information, you can email us anytime at

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