Volume 17 of the Encyclopedia of American Law (180-Volume)
VOLUME 17: FEDERAL RULES OF EVIDENCE
What the Jury Hears and What It Does Not
Introduction to Volume 17
The Federal Rules of Evidence govern the admissibility of evidence in federal court. They were adopted in 1975. They apply in civil and criminal cases. They are not a code of perfect justice. They are a set of practical rules designed to ensure that trials are fair, efficient, and reliable.
The Rules have two core principles. First, evidence must be relevant. Irrelevant evidence is not admissible. Second, even relevant evidence may be excluded if its probative value is substantially outweighed by the danger of unfair prejudice, confusion, or waste of time.
The Rules also exclude certain categories of evidence for policy reasons: hearsay, character evidence, evidence of prior crimes, and privileged communications. These exclusions reflect a judgment that the risks of the evidence outweigh its value.
This volume proceeds in the order of the Rules. Part One covers the foundational rules: relevance, character evidence, and the probative value/prejudice balance. Part Two covers hearsay: the definition, the exceptions, and the Confrontation Clause. Part Three covers expert testimony: the Daubert standard, the Frye standard, and the distinction between expert and lay opinion. Part Four covers privileges: attorney‑client, spousal, psychotherapist‑patient, and others. Part Five covers authentication, the best evidence rule, and judicial notice.
The Rules are not a mystery. They are tools. A lawyer who masters the Rules can shape the story that the jury hears.
PART ONE: RELEVANCE
Chapter 1: The Basic Rule – Rule 401 and 402
Rule 401 defines relevance. Evidence is relevant if it has any tendency to make a fact more or less probable than it would be without the evidence, and the fact is of consequence in determining the action.
The standard is low. A brick is not a wall. Relevance is a brick. It does not need to prove the case. It needs only to move the needle.
Rule 402 states the basic principle: relevant evidence is admissible unless the Rules or the Constitution provide otherwise. Irrelevant evidence is not admissible.
The Rules do not require that the evidence be offered by a party. The court may admit evidence on its own motion.
Chapter 2: Unfair Prejudice – Rule 403
Rule 403 is the most important rule of evidence. It provides that the court may exclude relevant evidence if its probative value is substantially outweighed by the danger of unfair prejudice, confusing the issues, misleading the jury, undue delay, wasting time, or needlessly presenting cumulative evidence.
The balance is in favor of admissibility. The court should exclude evidence only when the probative value is substantially outweighed, not merely outweighed. Unfair prejudice means an undue tendency to suggest decision on an improper basis, such as emotion, sympathy, or hatred.
Rule 403 is a rule of judicial discretion. The trial court’s decision is reviewed for abuse of discretion. The appellate court will reverse only if the trial court’s ruling is arbitrary or irrational.
Chapter 3: Character Evidence – Rule 404
Rule 404(a) states the general rule: evidence of a person’s character is not admissible to prove that the person acted in accordance with that character on a particular occasion.
The rule is a rule of policy. Character evidence is excluded because it is overvalued by juries. A jury might convict a person because the person has a bad character, not because the evidence shows that the person committed the crime.
Exceptions in criminal cases: The defendant may offer evidence of the defendant’s own good character for a relevant trait. The prosecution may respond with evidence of the defendant’s bad character for the same trait. The prosecution may also offer evidence of the victim’s character to prove that the victim was the first aggressor. The defendant may respond with evidence of the victim’s good character for peacefulness.
Rule 404(b) permits evidence of other crimes, wrongs, or acts for non‑character purposes: proof of motive, opportunity, intent, preparation, plan, knowledge, identity, absence of mistake, or lack of accident.
The prosecution must give reasonable notice of its intent to use Rule 404(b) evidence. The court must conduct a balancing test under Rule 403. The evidence must be relevant to a non‑character purpose. The probative value must not be substantially outweighed by the danger of unfair prejudice.
Chapter 4: Habit and Routine Practice – Rule 406
Rule 406 permits evidence of a person’s habit or an organization’s routine practice to prove that the person or organization acted in accordance with the habit or routine on a particular occasion.
Habit is more specific than character. Character describes a general disposition. Habit describes a regular response to a specific situation. A person may have the character trait of being careful. A person may have the habit of checking the rearview mirror before changing lanes.
Habit evidence is admissible because it is more probative than character evidence. Habit evidence is also less likely to be overvalued by the jury.
Chapter 5: Subsequent Remedial Measures – Rule 407
Rule 407 provides that evidence of subsequent remedial measures is not admissible to prove negligence, culpable conduct, a defect in a product or design, or a need for a warning.
The rule encourages people to take safety measures. If the evidence were admissible, a person might not fix a dangerous condition for fear that the fix would be used against them.
The rule does not bar evidence for other purposes: proving ownership, control, or the feasibility of precautionary measures.
Chapter 6: Compromise Offers – Rule 408
Rule 408 provides that evidence of compromise offers is not admissible to prove liability or the validity of a claim. The rule also bars evidence of conduct or statements made during compromise negotiations.
The rule encourages settlement. If a party knew that offers of compromise could be used against them, the party would be less likely to negotiate.
The rule does not bar evidence for other purposes: proving bias or prejudice of a witness, negating a contention of undue delay, or proving an effort to obstruct a criminal investigation.
Chapter 7: Offers to Pay Medical Expenses – Rule 409
Rule 409 provides that evidence of offers to pay medical expenses is not admissible to prove liability. Unlike Rule 408, Rule 409 does not bar evidence of statements made in connection with the offer. A statement such as “I am sorry I hit you, let me pay your bills” is admissible for the admission, not the offer to pay.
Chapter 8: Plea Bargaining – Rule 410
Rule 410 provides that evidence of the following is not admissible in a criminal case:
- A plea of guilty later withdrawn.
- A plea of nolo contendere.
- A statement made during a plea discussion.
The rule encourages plea bargaining. The government may not use the defendant’s offer to negotiate as evidence of guilt.
The rule does not bar evidence for other purposes: a statement made in a plea discussion that is later offered in a perjury prosecution.
PART TWO: HEARSAY
Chapter 9: The Definition – Rule 801
Hearsay is a statement that:
- The declarant does not make while testifying at the current trial or hearing.
- A party offers in evidence to prove the truth of the matter asserted.
A statement may be oral, written, or nonverbal conduct intended as an assertion.
Not hearsay: a statement offered for a purpose other than the truth of the matter asserted. A statement offered to show that the statement was made (perjury, notice, knowledge) is not hearsay. A statement offered to show the effect on the listener (the listener heard the statement and acted) is not hearsay.
Rule 801(d) provides two categories of statements that are not hearsay even though they are offered for truth:
Prior inconsistent statement of a witness. If the declarant testifies and is subject to cross‑examination, a prior inconsistent statement is not hearsay. The statement must have been made under penalty of perjury at a trial, hearing, or deposition.
Prior consistent statement of a witness. If the declarant testifies and is subject to cross‑examination, a prior consistent statement is not hearsay. The statement is admissible to rebut a charge of recent fabrication or improper influence.
Statement of a party opponent. A statement of a party is not hearsay. The statement need not have been against interest when made. Any statement of a party, including a statement of a predecessor in interest, is admissible.
Chapter 10: Hearsay Exceptions – Availability of Declarant Immaterial
Rule 803 lists exceptions that apply regardless of whether the declarant is available to testify.
Present sense impression (803(1)). A statement describing or explaining an event or condition made while the declarant was perceiving the event or immediately thereafter.
Excited utterance (803(2)). A statement relating to a startling event or condition made while the declarant was under the stress of excitement caused by the event or condition.
Then‑existing mental, emotional, or physical condition (803(3)). A statement of the declarant’s then‑existing state of mind, emotion, sensation, or physical condition. The statement may not be a statement of memory or belief to prove the fact remembered.
Statements for purposes of medical diagnosis or treatment (803(4)). A statement made for and reasonably pertinent to medical diagnosis or treatment. The statement may describe medical history, past symptoms, or the cause of the condition.
Recorded recollection (803(5)). A record that is on a matter the witness once knew but now cannot recall well enough to testify fully. The record must have been made when the matter was fresh in the witness’s memory. The record must be accurate. The record may be read into evidence. It may not be received as an exhibit unless offered by an adverse party.
Business records (803(6)). A record of an act, event, or condition made at or near the time by a person with knowledge, kept in the course of a regularly conducted business activity, and made as a regular practice of that business. The opponent must not show a lack of trustworthiness.
Public records (803(8)). A record of a public office that sets out the office’s activities, a matter observed under a legal duty to report (except in criminal cases for matters observed by law enforcement personnel), or factual findings from a legally authorized investigation.
Ancient documents (803(16)). A document in existence for 20 years or more whose authenticity is established.
Learned treatises (803(18)). A statement contained in a treatise, periodical, or pamphlet if the statement is called to the attention of an expert witness on cross‑examination or relied on by the expert on direct examination. The statement may be read into evidence. It may not be received as an exhibit.
Judgment of previous conviction (803(22)). A judgment of a felony conviction offered for any purpose. Not admissible when offered by the defendant in a criminal case to prove the conduct of a non‑party.
Chapter 11: Hearsay Exceptions – Declarant Unavailable
Rule 804 applies when the declarant is unavailable. Unavailability includes:
- Exemption by privilege.
- Refusal to testify despite court order.
- Lack of memory.
- Death or physical or mental illness.
- Absence from the hearing and the proponent’s inability to procure attendance by subpoena.
Former testimony (804(b)(1)). Testimony given at a previous trial, hearing, or deposition. Offered against a party who had an opportunity and similar motive to develop the testimony.
Statement under belief of imminent death (dying declaration) (804(b)(2)). A statement made by a declarant who believed that death was imminent. Admissible only in a homicide case or a civil case.
Statement against interest (804(b)(3)). A statement that a reasonable person in the declarant’s position would have made only if it were true because it was so contrary to the declarant’s interest. The declarant must be unavailable.
Statement of personal or family history (804(b)(4)). A statement about the declarant’s own birth, adoption, marriage, divorce, or other similar fact.
Forfeiture by wrongdoing (804(b)(6)). A statement offered against a party who wrongfully caused the declarant’s unavailability.
Chapter 12: Residual Exception – Rule 807
Rule 807 is a catchall exception. A hearsay statement not covered by a specific exception is admissible if:
- The statement has equivalent circumstantial guarantees of trustworthiness.
- The statement is offered as evidence of a material fact.
- The statement is more probative on the point than any other evidence that the proponent can obtain through reasonable efforts.
- Admitting the statement will best serve the purposes of the Rules and the interests of justice.
- The proponent gives reasonable notice to the adverse party.
The residual exception is used sparingly. The specific exceptions take priority.
Chapter 13: The Confrontation Clause
The Sixth Amendment gives a criminal defendant the right to confront witnesses. The Confrontation Clause limits the admissibility of hearsay in criminal cases.
Crawford v. Washington (2004) held that testimonial hearsay is inadmissible unless the declarant is unavailable and the defendant had a prior opportunity to cross‑examine. The Roberts reliability test was abandoned.
Testimonial statements include:
- Statements made to law enforcement for the purpose of gathering evidence.
- Depositions.
- Grand jury testimony.
- Affidavits.
Non‑testimonial statements include:
- Statements made to police in an emergency.
- Business records.
- Co‑conspirator statements.
The Confrontation Clause applies only in criminal cases. It does not apply in civil cases.
PART THREE: OPINIONS AND EXPERT TESTIMONY
Chapter 14: Lay Opinion – Rule 701
A lay witness may testify in the form of an opinion if:
- The opinion is rationally based on the witness’s perception.
- The opinion is helpful to a clear understanding of the witness’s testimony or the determination of a fact in issue.
- The opinion is not based on scientific, technical, or other specialized knowledge.
Examples of permissible lay opinion: a witness may state that the car was speeding, that the person appeared intoxicated, that the handwriting looked authentic.
Chapter 15: Expert Testimony – Rule 702
Rule 702 governs expert testimony. A witness qualified as an expert by knowledge, skill, experience, training, or education may testify if:
- The expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue.
- The testimony is based on sufficient facts or data.
- The testimony is the product of reliable principles and methods.
- The expert has reliably applied the principles and methods to the facts of the case.
The rule incorporates the Daubert standard.
Chapter 16: Daubert and Frye
Daubert v. Merrell Dow Pharmaceuticals, Inc. (1993) established the standard for expert testimony in federal court. The trial court acts as a gatekeeper. The court must ensure that the expert testimony is both relevant and reliable.
The Court listed factors that the trial court may consider:
- Whether the theory or technique can be or has been tested.
- Whether the theory or technique has been subjected to peer review and publication.
- The known or potential rate of error.
- The existence and maintenance of standards controlling the technique’s operation.
- General acceptance in the relevant scientific community.
The “general acceptance” test came from Frye v. United States (1923) . Frye was the old standard. Daubert replaced it in federal court. Some states still follow Frye.
In Kumho Tire Co. v. Carmichael (1999) , the Court held that Daubert applies to all expert testimony, not just scientific testimony. The trial court’s gatekeeping function extends to technical and other specialized knowledge.
Chapter 17: Bases of Expert Testimony – Rule 703
An expert may base an opinion on facts or data that the expert has been made aware of or personally observed. The expert may rely on inadmissible evidence if experts in the field reasonably rely on that kind of evidence.
The underlying facts or data need not be admitted. The expert may disclose them to the jury only if their probative value substantially outweighs the danger of unfair prejudice.
Chapter 18: Opinion on Ultimate Issue – Rule 704
An expert may state an opinion on the ultimate issue in the case. The rule abolished the old prohibition.
In a criminal case, however, an expert may not state an opinion about whether the defendant had the mental state required for the offense. That is a matter for the jury alone.
PART FOUR: PRIVILEGES
Chapter 19: Attorney‑Client Privilege
The attorney‑client privilege is the oldest privilege recognized at common law. It protects communications between a lawyer and a client made for the purpose of seeking legal advice.
The privilege belongs to the client. Only the client may waive it. The lawyer must assert it on the client’s behalf.
The privilege does not protect:
- The fact of representation.
- The fee arrangement.
- Communications made to further a crime or fraud (crime‑fraud exception).
- Communications between a lawyer and a client when the lawyer is not acting as a lawyer.
Chapter 20: Work Product Doctrine
Rule 26(b)(3) of the Federal Rules of Civil Procedure codifies the work product doctrine. Documents and tangible things prepared in anticipation of litigation are protected.
Ordinary work product may be discovered on a showing of substantial need and inability to obtain the substantial equivalent without undue hardship. Opinion work product (the lawyer’s mental impressions) is not discoverable.
Chapter 21: Spousal Privileges
Two spousal privileges exist.
Spousal immunity prevents the government from compelling a witness to testify against the spouse in a criminal case. The privilege belongs to the witness‑spouse. The witness may choose to testify. The privilege applies only while the marriage is valid. It does not apply after divorce.
Marital communications privilege protects confidential communications made during marriage. Either spouse may assert it. The privilege survives divorce. It does not apply to communications made to further a crime or fraud.
Chapter 22: Psychotherapist‑Patient Privilege
Jaffee v. Redmond (1996) recognized a psychotherapist‑patient privilege. The privilege protects confidential communications between a licensed psychotherapist and a patient. The purpose is to encourage patients to seek treatment without fear of disclosure.
The privilege does not apply when the patient puts the mental condition in issue (the patient sues for emotional distress). It does not apply in criminal cases when the defendant raises a defense of insanity.
Chapter 23: Other Privileges
The Federal Rules of Evidence do not attempt to list all privileges. Rule 501 provides that privileges are governed by the common law, as interpreted by the courts, in light of reason and experience.
Other recognized privileges include:
- Clergy‑communicant privilege. Protects confidential communications made to a clergy member for spiritual guidance.
- Physician‑patient privilege. Recognized in most states but not uniformly in federal court. The federal courts have recognized a limited privilege.
- Parent‑child privilege. Not widely recognized.
- Accountant‑client privilege. Not recognized at common law. Some statutes create a limited privilege.
PART FIVE: AUTHENTICATION, BEST EVIDENCE, AND JUDICIAL NOTICE
Chapter 24: Authentication – Rule 901
Rule 901 requires the proponent of evidence to produce evidence sufficient to support a finding that the item is what the proponent claims it is. The standard is low. The proponent need not prove authenticity beyond a reasonable doubt. The proponent need only produce enough evidence that a reasonable jury could find the item authentic.
Examples of authentication:
- Testimony of a witness with knowledge.
- Comparison by an expert witness or the trier of fact.
- Distinctive characteristics (appearance, contents, substance, internal patterns).
- Voice identification by opinion.
- Telephone conversations (self‑identification).
- Public records (certified copy).
- Ancient documents (20 years old, in a condition unlikely to create suspicion).
- Self‑authenticating documents: certified copies of public records, newspapers, trade inscriptions, acknowledged documents, commercial paper.
Chapter 25: Best Evidence Rule – Rule 1001‑1008
The best evidence rule applies only to writings, recordings, and photographs. The rule requires the original to prove the content of a writing. A duplicate is admissible to the same extent as the original unless there is a genuine question about authenticity or it would be unfair to admit the duplicate.
The original is not required when:
- The originals are lost or destroyed (unless the proponent destroyed them in bad faith).
- The original is not obtainable by judicial process.
- The original is in the possession of the opponent and the opponent does not produce it.
- The writing is not closely related to a controlling issue.
- The evidence is a summary of voluminous writings.
Chapter 26: Judicial Notice – Rule 201
Rule 201 permits the court to take judicial notice of adjudicative facts. A judicially noticed fact must be one that is not subject to reasonable dispute because it is generally known within the court’s territorial jurisdiction or can be accurately and readily determined from sources whose accuracy cannot reasonably be questioned.
The court may take judicial notice on its own motion or on a party’s request. The court must instruct the jury to accept the fact as conclusive. In a criminal case, the court may not take judicial notice of an element of the offense.
APPENDIX 1: GLOSSARY
Authentication – The process of proving that evidence is what the proponent claims it is.
Best evidence rule – A rule requiring the original writing, recording, or photograph to prove the content of the document.
Character evidence – Evidence of a person’s general disposition. Generally not admissible to prove conduct on a particular occasion.
Confrontation Clause – The Sixth Amendment provision that gives criminal defendants the right to confront witnesses. Limits the admissibility of testimonial hearsay.
Daubert standard – The standard for admissibility of expert testimony. The trial court acts as gatekeeper and must ensure that the testimony is relevant and reliable.
Dying declaration – A statement made under a belief of imminent death. Admissible in homicide cases and civil cases.
Excited utterance – A statement relating to a startling event made while the declarant was under the stress of the event. Hearsay exception.
Habit – A person’s regular response to a specific situation. Admissible to prove conduct on a particular occasion.
Hearsay – A statement made out of court offered to prove the truth of the matter asserted. Generally not admissible unless an exception applies.
Judicial notice – The court’s acceptance of a fact that is not reasonably in dispute.
Lay opinion – Opinion testimony by a witness who is not an expert.
Present sense impression – A statement describing an event made while the declarant was perceiving the event. Hearsay exception.
Relevance – The tendency of evidence to make a fact more or less probable than it would be without the evidence.
Residual exception – A catchall hearsay exception for statements with equivalent guarantees of trustworthiness.
Statement against interest – A statement that a reasonable person would have made only if it were true because it was contrary to the declarant’s interest. Hearsay exception.
Unfair prejudice – The undue tendency of evidence to suggest a decision on an improper basis. Evidence may be excluded under Rule 403 if its probative value is substantially outweighed by the danger of unfair prejudice.
Work product – Documents and tangible things prepared in anticipation of litigation. Protected from discovery.
APPENDIX 2: SELECT BIBLIOGRAPHY
Broun, Kenneth S. McCormick on Evidence. 8th ed. West Academic, 2020.
Carlson, Ronald L., Edward J. Imwinkelried, and Edward J. Kionka. Evidence: Teaching Materials for an Integrated Approach. 6th ed. West Academic, 2019.
Cleary, Edward W. “The Federal Rules of Evidence: A New Approach to the Admissibility of Evidence.” American Bar Association Journal 61 (1975): 53.
Faigman, David L., David H. Kaye, and Michael J. Saks. Modern Scientific Evidence: The Law and Science of Expert Testimony. 4th ed. West Academic, 2020.
Fisher, George. Evidence. 4th ed. Foundation Press, 2021.
Friedman, Richard D. “The Confrontation Clause and the Federal Rules of Evidence.” Minnesota Law Review 98 (2014): 1331.
Imwinkelried, Edward J. The New Wigmore: A Treatise on Evidence. 3d ed. Wolters Kluwer, 2020.
Lilly, Graham C., Daniel J. Capra, and Stephen A. Saltzburg. Principles of Evidence. 8th ed. West Academic, 2019.
Mueller, Christopher B., and Laird C. Kirkpatrick. Evidence. 6th ed. Wolters Kluwer, 2018.
Park, Roger C., and David P. Leonard. Evidence: A Problems Approach. 3d ed. West Academic, 2018.
Saltzburg, Stephen A., and Daniel J. Capra. Federal Rules of Evidence Manual. 12th ed. LexisNexis, 2020.
Slobogin, Christopher. Proving the Unprovable: The Role of Law, Science, and Speculation in Adjudicating Culpability and Dangerousness. Oxford University Press, 2007.
Strong, John W., and Kenneth S. Broun. McCormick on Evidence. 8th ed. West Academic, 2020.
Tillers, Peter. “The Federal Rules of Evidence and the Problem of Hearsay.” Cardozo Law Review 33 (2012): 1591.
Weissenberger, Glen. Federal Rules of Evidence: Rules, Legislative History, Commentary, and Authority. 8th ed. LexisNexis, 2020.
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