Federal Rule of Evidence 401
Admissibility of evidence, and the weight of that evidence, are two different things. Evidence is either relevant, or it is irrelevant. Relevant evidence may be admissible. Irrelevant evidence is never admissible. Thus, every piece of evidence an advocate seeks to introduce must be relevant.
The Federal Rules of Evidence (FRE) have codified this doctrine within Article IV. FRE 401 gives the definition relevance and FRE 403 provides a framework for when relevant evidence may be excluded. The rest of the 400s put limits in very specific circumstances as to when relevant evidence is automatically excluded (or included).
FRE 401 states “[e]vidence is relevant if: (a) it has any tendency to make a fact more or less probable than it would be without the evidence; and (b) the fact is of consequence in determining the action.” Pay close attention to the language of this rule: “any tendency.” This is an extremely low bar to meet. What you do not want to do is waste your time, or the court’s time, making frivolous relevance objections just for the sake of objecting.
Further, keep in mind that FRE 401 interplays with almost every other FRE rule. You have a hearsay exception? Great, but does it pass FRE 401? You found a non-propensity purpose for trying to bring in character evidence under FRE 404(b)? Excellent, but is that purpose relevant to the case? Irrelevant evidence wastes the court’s time, distracts from the real issues at hand, and is inadmissible.
Federal Rule of Evidence 403
All relevant is not admissible. FRE 403 exists as the most general rule to exclude relevant evidence. It states that “[t]he court may exclude relevant evidence if its probative value is substantially outweighed by a danger of one or more of the following: unfair prejudice, confusing the issues, misleading the jury, undue delay, wasting time, or needlessly presenting cumulative evidence.” Unlike FRE 401, FRE 403 is NOT a low bar. The advisory committee states that “[i]n reaching a decision whether to exclude on grounds of unfair prejudice, consideration should be given to the probable effectiveness or lack of effectiveness of a limiting instruction.” A limiting instruction is when the judge allows evidence in only for a specific purpose.
Most evidence you want to admit against a witness, or the other side, is prejudicial. The question is whether it is UNFAIRLY prejudicial. You may be wondering, what probative value means? Black’s Law Dictionary states the definition of probative as “[t]ending to prove or disprove.” You can think of probative value almost like the level of importance to the case.
Federal Rules of Evidence 407 – 411
FRE 407, 408, 409, 410, and 411 are rules which cover very specific situations in which relevant evidence is automatically excluded except under particular circumstances. The reasoning behind most of these rules lies in public policy. For example, FRE 407 covers subsequent remedial measures. The rule states:
When measure are taken that would have made an earlier injury or harm less likely to occur, evidence of the subsequent measures is not admissible to prove:
- culpable conduct;
- a defect in a product or its design; or
- a need for a warning or instruction.
But the court may admit this evidence for another purpose, such as impeachment or – if disputed – proving ownership, control, or the feasibility of precautionary measures.
Take yourself out of the context of a trial, or anything to do with the legal field and ask yourself the following question: do we want to encourage one to fix their mistakes? Of course we do! Let’s say a train station had a broken railing. Someone fell as a result and sued them for negligence. A week after the person fell, the railing was fixed. If the attorney was allowed to introduce evidence of the fixed railing for the purpose of demonstrating a breach of negligence, the rail company would likely be deterred from fixing the rail, wouldn’t they?
FRE 408, 409, 410 and 411 are all very similar to FRE 407 in that their purposes are to encourage engaging in settlement discussions, to encourage medical attention, to encourage plea deals, and to encourage having liability insurance. Evidence or testimony that falls under sections 407-411 of the FRE have their exceptions.
This is the reason why you always have to ask yourself what the purpose is in offering certain evidence or eliciting certain testimony. If you are drafting a direct or cross examination, it is always good practice to go through, question by question, and ask yourself what the purpose is.
 FRE 401 (emphasis added)
 FRE 401
 Deborah Jones Merritt & Ric Simmons, Learning Evidence: From the Federal Rules to the Courtroom, 55 (5th ed. 2022)
 FRE 403 (emphasis added)
 FRE 403 Advisory Committee’s Note
 FRE 105
 Probative, Black’s Law Dictionary (11th ed. 2019)
 FRE 407
 Deborah Jones Merritt & Ric Simmons, Learning Evidence: From the Federal Rules to the Courtroom, 90 (5th ed. 2022)