Relevance and its limits, the hearsay rule and the exceptions that swallow much of it, authentication of records and electronic material, expert testimony and its gatekeeping, privileges and their waiver, judicial notice, and burdens and presumptions.
Federal Rule of Evidence 701 permits a witness not testifying as an expert to give an opinion that is rationally based on the witness's own perception, helpful to clearly understanding the testimony or determining a fact in issue, and not based on scientific, technical or other specialized knowledge within the scope of Rule 702. Rule 602 separately requires personal knowledge, and the two provisions together mark the boundary against expert opinion in ordinary clothing.
Federal Rule of Evidence 804 makes certain hearsay admissible only once the declarant is shown to be unavailable. Rule 804(a) defines unavailability through five grounds: privilege, refusal despite an order, lack of memory, death or infirmity, and absence the proponent could not overcome. Rule 804(b) then admits former testimony, statements made under a belief of imminent death, statements against interest, statements of family history, and statements against a party that caused the absence.
Federal Rule of Evidence 404(a) prohibits evidence of a person's character or character trait offered to prove that the person acted in accordance with it on a particular occasion. Rule 404(b) permits evidence of other crimes, wrongs or acts when offered for a purpose other than propensity, such as motive, intent, knowledge, identity or absence of mistake. Rule 405 controls the permitted methods of proof, and Rule 406 treats habit and routine practice as outside the prohibition entirely.
Federal Rule of Evidence 201 permits judicial notice of an adjudicative fact not subject to reasonable dispute because it is generally known in the trial court's territory or can be accurately and readily determined from unquestionable sources. In a civil case the jury must accept a noticed fact; in a criminal case it may but need not. Rule 301 provides that a presumption in a civil case shifts the burden of producing evidence to rebut it but does not shift the burden of persuasion.
Federal Rule of Evidence 803 lists hearsay exceptions that apply regardless of whether the declarant is available as a witness. They include the present sense impression, the excited utterance, a then-existing mental or physical condition, statements made for medical diagnosis or treatment, recorded recollection, records of a regularly conducted activity, the absence of such a record, public records, and several categories of reputation and judgment evidence. Each carries its own foundation.
Federal Rule of Evidence 901(a) requires the proponent of an item to produce evidence sufficient to support a finding that the item is what the proponent claims. Rule 901(b) lists non-exclusive illustrations, among them a witness with knowledge, distinctive characteristics, voice identification, and proof about a process or system. Rule 902 then makes whole categories self-authenticating, including sealed public documents, certified public records, and certified business and machine records.
Federal Rule of Evidence 801 defines hearsay as a statement the declarant did not make while testifying at the current trial or hearing, offered to prove the truth of the matter asserted. Rule 802 makes hearsay inadmissible unless a federal statute, the rules, or a Supreme Court rule provides otherwise. Rule 801(d) removes two categories from the definition altogether: certain prior statements by a testifying witness, and statements offered against an opposing party.
Federal Rule of Evidence 501 provides that the common law, as interpreted by federal courts in the light of reason and experience, governs privilege, unless the Constitution, a federal statute or a Supreme Court rule provides otherwise. In a civil case where state law supplies the rule of decision, state law governs privilege on that element. Rule 502 then limits the consequences of disclosure, controlling subject matter waiver, inadvertent production and court orders.
Federal Rule of Evidence 702 admits expert opinion where the witness is qualified by knowledge, skill, experience, training or education, and where the proponent shows that the testimony rests on sufficient facts or data, is the product of reliable principles and methods, and reflects a reliable application of those principles to the facts. Daubert assigns the trial court a gatekeeping role, and Kumho Tire extends it to technical and experience-based expertise as well as scientific testimony.
Federal Rule of Evidence 401 makes evidence relevant if it has any tendency to make a fact of consequence more or less probable. Rule 402 admits relevant evidence unless another rule excludes it and bars irrelevant evidence outright. Rule 403 then allows a trial judge to exclude relevant evidence when its probative value is substantially outweighed by unfair prejudice, confusion, misleading the jury, delay, or needless repetition.
Federal Rule of Evidence 1002 requires an original writing, recording or photograph to prove its content, unless the rules or a federal statute provide otherwise. Rule 1001 defines original broadly enough to include any printout of electronically stored information that accurately reflects the data. Rule 1003 admits duplicates on the same footing absent a genuine question of authenticity, and Rule 1004 permits other evidence of content when the original is lost, destroyed or beyond reach.
