§ 9.01 Overview of Relevancy Rules

• Jurisdiction: United States

§ 9.01 Overview of Relevancy Rules

Relevancy is the most pervasive concept in evidence law and the threshold issue for all evidence. If evidence is not relevant, it should be excluded.¹ Period. If the evidence is relevant, then the next step focuses on whether some other evidentiary rule requires exclusion. For example, relevant evidence may be excluded because it contravenes the hearsay rule or the best evidence rule. Thus, relevancy is a necessary but (sometimes) not a sufficient condition of admissibility.

Basic relevance rules. Federal Rule 401 defines relevant evidence (probative value). Rule 402 makes relevant evidence admissible in the absence of a rule of exclusion. Rule 403 specifies the circumstances under which a trial court is permitted to exclude relevant evidence. These three rules set forth the general provisions governing relevancy.

There are an almost infinite variety of relevancy problems. Often precedent is of little help because the issues arise in slightly different circumstances. There are, however, some situations that are "repeat players." Some of these, such as "similar happenings," "adverse inferences," and "out-of-court experiments," are discussed later in this chapter.

Special relevance rules. In some situations, an issue recurs so frequently that the courts develop categorical rules. For instance, character evidence is generally prohibited, although there are exceptions. Rules 404, 405, and 412-15 deal explicitly with character.² Rule 406 governs habit evidence.³ Similarly, evidence of liability insurance is generally inadmissible (Rule 411).⁴

Ancillary rules based on policy. Rules 407-410 are relevance rules of a different kind. They all involve the exclusion of relevant evidence based on policy reasons external to the truth-seeking function of the trial. For example, subsequent remedial measures (Rule 407) are excluded in order to encourage people to make repairs after accidents. Offers to compromise are excluded under Rule 408 (civil cases) and Rule 410 (criminal cases) in order to encourage parties to settle cases.⁵ Evidence of the payment of medical expenses is excluded under Rule 409 in order to encourage people to pay such expenses after accidents...