Federal Rules of Evidence
Federal Rules of Evidence (Forensic Science)
The rules of evidence used in U.S. courts have evolved with the jury system. Until 1975, when they were codified under the Federal Rules of Evidence, these rules existed independently in the form of judicial decisions, mandates, and separate statutes. The Federal Rules of Evidence govern procedures in the federal courts, but they are not applicable to state court proceedings. Each U.S. state has its own rules of evidence, although many states have used the federal rules as models or prototypes.
The general purpose of rules of evidence is to regulate the evidence that juries may use to reach their verdicts. The rules address some basic concepts, such as relevance, eliminating unfair surprise, efficiency, reliability, and overall fairness in the adversary process, and they also permit judges broad discretion to admit evidence or exclude evidence within certain parameters, ensuring that juries have a broad spectrum of evidence before them, but not so much that the evidence becomes cumulative, repetitive, inflammatory, or confusing.
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Types of Evidence (Forensic Science)
Two basic types of evidence are recognized: direct and circumstantial. Direct evidence tends to establish the fact in question without additional proof. A fact is established based on the credibility or value of the evidence, without the need for further inference. Circumstantial evidence requires the fact finder (the jury in a jury trial, the judge in a bench trial) to make inferences or draw conclusions. For example, a person wakes up find to snow on the ground in the morning when it was clear and dry the night before; the observer did not personally see the snow falling but can infer that it snowed during the night.
Testimonial evidence is based on the testimony of witnesses; nontestimonial evidence (also called real or tangible evidence) is based on physical objects or items designed to assist the fact finder (called demonstrative evidence) such as maps or diagrams of crime scenes.
The admissibility of evidence at trial depends on the rules. The fact finder is permitted to evaluate only admissible evidence. All relevant evidence is admissible only if it is competent (legally adequate). Relevant evidence tends to prove or disprove a disputed issue. Irrelevant evidence wastes time and is often prejudicial. It may also confuse the jury. Sometimes, however, even relevant evidence can be inadmissible because its probative value is outweighed by the danger of unfair prejudice or confusion. Probative evidence tends to...
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Admissibility of Scientific Evidence (Forensic Science)
The landmark case for the admissibility of scientific procedures and their results is Frye v. United States (1923). The Frye standard requires the trial court to determine whether the scientific theory or scientific method used to generate evidence is generally accepted as reliable in the scientific community. This has become known as the Frye test. After the Federal Rules of Evidence were adopted in 1975, Rule 702 stated that expert witnesses may testify in the form of opinion if their specialized knowledge will help the jury to understand the evidence or determine a disputed fact. Although Rule 702 relaxed the stringent Frye standard, it gave little guidance as to what would be helpful to the fact finder.
In its 1993 decision in the case of Daubert v. Merrell Dow Pharmaceuticals, the U.S. Supreme Court agreed that the trial court has a gatekeeper function: to make sure that admitted scientific evidence and expert testimony are reliable and relevant. Daubert set out a checklist for trial courts to use in assessing the reliability of scientific expert testimony, suggesting factors such as standards and controls, testing, peer review, error rate, and acceptability that could be helpful in determining the reliability of a scientific theory or technique. During the early twenty-first century, more state courts use the Daubert test for...
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Character Evidence (Forensic Science)
Character is a collection of traits and features that make up a person’s disposition or nature, evidenced by a consistent pattern of behavior. Character traits include honesty, courage, and integrity as well as such negative traits as dishonesty, violence, and recklessness. In criminal cases, character evidence is generally inadmissible to prove conduct to show that a person acted in conformity with a particular character trait on a particular occasion. The prosecution is not permitted to introduce evidence of the defendant’s bad character, such as violent tendencies, but the defense has the option to introduce evidence of good character, such as honesty.
If the defense elects to introduce a character witness to testify about the defendant’s good character, this is said to “open the door” for the prosecution to provide rebuttal evidence. If the defense does not choose to introduce a character witness, the prosecution may not comment on that fact to the jury.
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Hearsay Evidence (Forensic Science)
Hearsay is defined in rule 801(c) of the Federal Rules of Evidence as “a statement, other than one made by the declarant while testifying at the trial or hearing, offered in evidence to prove the truth of the matter asserted.” It is excluded because the witness is not testifying from personal knowledge but from repetition of what was said or written outside court by another person who is not present, offered for the purpose of establishing the truth. The out-of-court declarant may have been lying, joking, or speaking carelessly, and the opposing side has no opportunity to cross-examine the declarant to impeach or test that person’s credibility. Additionally, given that the statement was made out of court, the demeanor of the declarant could not be observed by the fact finder. Alternatively, the testifying witness may have a faulty memory, poor hearing, or another infirmity. The exclusion of hearsay testimony prevents unreliable evidence from being considered. It should be noted that statements that otherwise would qualify as hearsay are admissible if they are introduced not to prove the truth of the matter asserted but merely to show that a statement was made.
Numerous exceptions to the hearsay rule exist, making otherwise inadmissible hearsay evidence reliable and admissible. These exceptions often involve surrounding circumstances that ensure the reliability of the evidence.
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Further Reading (Forensic Science)
Broun, Kenneth S., ed. McCormick on Evidence. 6th ed. St. Paul, Minn.: Thomson/West, 2006. Considered to be the bible of the law of evidence. Contains detailed explanations and case references.
Graham, Michael H. Federal Rules of Evidence in a Nutshell. 7th ed. St. Paul, Minn.: West, 2007. Provides a concise summary of the Federal Rules of Evidence; useful as a reference tool.
James, Stuart H., and Jon J. Nordby, eds. Forensic Science: An Introduction to Scientific and Investigative Techniques. 2d ed. Boca Raton, Fla.: CRC Press, 2005. Illustrated introductory text presents a clear overview of the subject. Includes several chapters devoted to legal issues in forensic science.
Pellicciotti, Joseph M. Handbook of Basic Trial Evidence: A College Introduction. Bristol, Ind.: Wyndham Hall Press, 1992. Comprehensive yet concise text outlines the rules of evidence and provides examples.
Stopp, Margaret T. Evidence Law in the Trial Process. Albany, N.Y.: West/Delmar, 1999. Discusses the rules of evidence and clarifies them with examples, explanations, and case excerpts.
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Federal Rules of Evidence (West's Encyclopedia of American Law)
The Federal Rules of Evidence generally govern civil and criminal proceedings in the courts of the United States and proceedings before U.S. BANKRUPTCY judges and U.S. magistrates, to the extent and with the exceptions stated in the rules. Promulgated by the U.S. Supreme Court and amended by Congress from time to time, the Federal Rules of Evidence are considered legislative enactments that have the force of statute, and courts interpret them as they would any other statute, employing traditional tools of statutory construction in applying their provisions.
The rules are designed to secure fairness in JUDICIAL ADMINISTRATION, to eliminate unjustifiable expense and delay, and to promote the growth and development of the law of evidence so that truth may be ascertained and proceedings justly resolved. Huff v. White Motor Corporation, 609 F.2d 286 (7th Cir. Ind. 1979). But the rules are not intended to result in an exhaustive search for a total and complete understanding of every civil and criminal case that comes before a federal court. Rather, the rules are meant to assist lawyer-adversaries and common sense triers-of-fact in resolving particularized legal disputes. Accordingly, the rules give courts authority to adapt the laws of evidence to circumstances as they arise.
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Federal Rules of Evidence (World of Forensic Science)
The Federal Rules of Evidence are broad principles promulgated by the United States Supreme Court governing the admissibility of any evidence in a criminal or civil trial. As such, they are applicable in trials in federal courts, although most state courts have adopted them as well. From the standpoint of forensic evidence, which is gathered, examined, and interpreted by specialists who are often called on to testify as expert witnesses, the key rule is Rule 702, Testimony by Experts: "If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise, if (1) the testimony is based upon sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case." A considerable body of case law applies this general principle to the facts of particular cases and defines standards for the admissibility of forensics evidence as interpreted by expert witnesses.
Historically, the courts relied on the Frye test, formulated by the Court in Frye v. United States in 1923. The case involved the admissibility of lie detector tests, at that time called "systolic blood pressure deception tests." This form of scientific evidence was then in its infancy and, at least according to the defendant, lacked what the Supreme Court would later call "sufficient facts or data" and "reliable principles and methods." The judge based his decision to admit the evidence on its "general acceptance in the particular field" (Frye, 293 F. at 1014). This was a key development, for it shifted the focus from the conclusions, even hunches, of a particular expert to an expertise recognized by other practitioners and gained from shared specialized training and experience. The Frye standard, however, had two principal problems: It failed to distinguish science from a pseudoscience such as astrology or, in the view of some legal experts, forensic science, and it rendered the court a passive observer, bound to accept expert testimony if it reflected "general acceptance in the particular field."
Accordingly, a new, more rigorous standard for the application of Rule 702 evolved from a 1993 case, Daubert v. Merrell Dow Pharmaceuticals, Inc. Under the Daubert standard, a trial judge can no longer defer to "general acceptance in the particular field" but must serve as a kind of gatekeeper by holding what are commonly called Daubert hearings, or pretrial hearings on the validity of the science in question using a five-pronged test: (1) whether the theory or technique can be and has been tested, (2) whether the theory or technique has been subjected to peer review and publication, (3) the known or potential rate of error, (4) the existence and maintenance of standards controlling the technique's operation, and (5) whether the theory or technique enjoys general acceptance within a relevant scientific community.
The relatively recent Daubert standard raised complex legal issues. Technically, it requires the courts to reexamine the validity and reliability of such forensics tools as polygraph testing, DNA testing, fingerprinting, handwriting analysis, fiber comparison, and the identification of firearms, bite marks, tire marks, and blood spatter patterns. Many of these are staples of forensic testimony, and some, such as fingerprint comparison, have a venerable century-old history, so the courts are reluctant to exclude them. Yet many observers, especially defense attorneys, contend that the research base that supports them is often inadequate, and they are increasingly launching attacks. In United States v. Havvard (2000), for example, the defense filed a motion to exclude the government's expert fingerprint witness, arguing that "there is no reliable statistical foundation for fingerprint comparisons and no reliable measure of error rates in latent print identification, especially in the absence of a specific standard about the number of points of identity needed to support an opinion as to identification" (Havvard, 117 F. Supp. 2d at 8501).
While the Court denied the defendant's motion, this type of challenge became more frequent after 1993 as defense attorneys become more sophisticated in their ability to assess and challenge scientific evidence. In the case of fingerprinting, for example, they are challenging the belief that a print match proves that the prints came from the same person. Defense attorneys note that fingerprint experts do not compare latent prints directly to known prints, but rather take points of comparison and then estimate the likelihood that the two came from the same person. More practically, defense attorneys challenge the reliability of forensics evidence (error rates), noting the many opportunities for error as evidence is found, bagged, labeled, transported, removed from storage, handled, examined, and re-stored.
SEE ALSO Evidence; Expert witnesses; Federal rules of evidence; Frye standard; U.S. Supreme Court (rulings on forensic evidence).