A witness who possesses specialized knowledge, skill, experience, training, or education that qualifies the witness to offer opinion testimony on matters beyond the understanding of ordinary jurors. The testimony must rest on sufficient facts or data, employ reliable principles and methods, and reflect a reliable application of those principles and methods to the facts of the case.
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How its tested
Common Examples
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Criminal Mental State Bar
In a federal prosecution for wire fraud, the government calls a forensic accountant to analyze ledgers showing fund transfers. The accountant describes the timing and amounts of the transfers but stops short of stating whether the defendant possessed the intent to defraud. The court admits the factual analysis while excluding any opinion on the defendant's mental state.
DNA Profile Basis Testimony
A state forensic analyst testifies that a DNA profile generated by an outside laboratory matches a profile produced from the defendant's blood sample. The analyst explains that the outside report served only as the foundation for her independent comparison and was not offered to prove the truth of its contents. The court permits the testimony over a confrontation objection.
During cross-examination of a retained toxicologist, defense counsel directs the witness to a passage in a peer-reviewed journal article on chemical exposure thresholds. The toxicologist acknowledges the article as a reliable authority and confirms that the passage contradicts part of her direct testimony. The court allows the passage to be read into the record.
General Acceptance Standard
A criminal defendant offers a psychologist to testify that a novel lie-detection technique establishes the defendant's truthfulness. The prosecution objects that the technique has not gained general acceptance in the scientific community. The court excludes the testimony after finding the method lacks the requisite acceptance among experts in the field.
Frye v. United States293 F. 1013, 1014 (D.C.Cir.1923)
Appellant, defendant below, was convicted of the crime of murder in the second degree, and from the judgment prosecutes this appeal. The case was submitted on November 7, 1923, and decided on December 3, 1923, by the Court of Appeals of the District of Columbia with Associate Justice Van Orsdel writing the opinion.
In the course of the trial counsel for defendant offered an expert witness to testify to the result of a deception test made upon defendant. The test is described as the systolic blood pressure deception test, and it is asserted that blood pressure is influenced by changes in the emotions of the witness, the systolic blood pressure rises being brought about by nervous impulses sent to the sympathetic branch of the autonomic nervous system.
Scientific experiments, it is claimed, have demonstrated that fear, rage, and pain produce a rise of systolic blood pressure, and that conscious deception or falsehood, concealment of facts, or guilt of crime, when accompanied by fear of detection while the person is under examination, raises the systolic blood pressure in a curve which corresponds to the struggle going on in the subject's mind between fear and attempted control of that fear as the examination touches the vital points in respect of which he is attempting to deceive the examiner.
Prior to the trial defendant was subjected to this deception test, and counsel offered the scientist who conducted the test as an expert to testify to the results obtained. The offer was objected to by counsel for the government, and the court sustained the objection. Counsel for defendant then offered to have the proffered witness conduct a test in the presence of the jury, and this also was denied.
Property owners retain an economist to calculate the economic impact of a rent-control ordinance on their apartment buildings. The economist compares pre- and post-ordinance cash flows and concludes that the regulation eliminates all reasonable investment-backed expectations. The court admits the calculations as evidence bearing on the takings claim.
Lingle, et al. v. Chevron U.S.A. Inc.544 U.S. 528, 537 (2005)
In 1997, the State of Hawaii had a highly concentrated wholesale oil market due to its small size and isolation over 1,600 miles from the mainland, with only two refineries and six gasoline wholesalers operating in the state. Chevron U.S.A. Inc. was the largest refiner and marketer, controlling 60 percent of the in-state gasoline market and 30 percent of the wholesale market on Oahu. Gasoline was sold at retail through approximately 300 service stations, about half leased by oil companies to independent lessee-dealers.
Chevron operated 64 such lessee-dealer stations under arrangements where it leased land, constructed stations, and leased them to dealers while setting wholesale prices and requiring supply contracts. In June 1997, the Hawaii Legislature enacted Act 257, which capped the rent oil companies could charge lessee-dealers at 15 percent of gross profits from gasoline sales plus 15 percent of other product sales, and imposed other restrictions on station ownership.
Thirty days after enactment, Chevron filed suit in the United States District Court for the District of Hawaii against the Governor and Attorney General, challenging the rent cap. The parties stipulated that the cap would reduce aggregate rent on 11 of Chevron's stations by about $207,000 per year but allow increases on the remaining 53, potentially raising overall rental income by nearly $1.1 million annually, and that Chevron had not recovered station maintenance costs through rent alone over the past 20 years.
The District Court granted summary judgment to Chevron. On appeal, the Ninth Circuit vacated the judgment and remanded the case. After a one-day bench trial featuring competing expert economists, the District Court entered judgment for Chevron. The Ninth Circuit affirmed, and the Supreme Court granted certiorari in 2004.
An indigent defendant charged with capital murder requests funds to retain a psychiatrist to evaluate his mental condition at the time of the offense. The trial court denies the request. On appeal the Supreme Court holds that the denial violated due process because the expert assistance was necessary to prepare an effective defense.
Ake v. Oklahoma470 U.S. 68 (1985)
Late in 1979, Glen Burton Ake was arrested and charged with murdering a couple and wounding their two children. He was arraigned in the District Court for Canadian County, Oklahoma, in February 1980. His behavior at arraignment and in other prearraignment incidents at the jail was so bizarre that the trial judge, sua sponte, ordered him to be examined by a psychiatrist for the purpose of advising with the Court as to his impressions of whether the Defendant may need an extended period of mental observation.
The examining psychiatrist reported that at times Ake appeared to be frankly delusional and claimed to be the sword of vengeance of the Lord. He diagnosed Ake as a probable paranoid schizophrenic and recommended a prolonged psychiatric evaluation to determine whether Ake was competent to stand trial. In March 1980, Ake was committed to a state hospital to be examined with respect to his present sanity. On April 10, the chief forensic psychiatrist informed the court that Ake was not competent to stand trial. The court held a competency hearing at which a psychiatrist testified that Ake was a psychotic with a diagnosis of paranoid schizophrenia chronic with exacerbation, that he was dangerous, and that he required a maximum security facility. The court found Ake to be a mentally ill person in need of care and treatment and incompetent to stand trial, and ordered him committed to the state mental hospital.
Six weeks later, the chief forensic psychiatrist informed the court that Ake had become competent to stand trial while receiving 200 milligrams of Thorazine three times daily. At a pretrial conference in June, Ake's attorney informed the court that his client would raise an insanity defense. Counsel requested that a psychiatrist examine Ake with respect to his mental condition at the time of the offense or that the court provide funds for such an examination. The trial judge denied the motion. Ake was tried for two counts of murder in the first degree and two counts of shooting with intent to kill. At the guilt phase, defense counsel called the psychiatrists who had examined Ake at the state hospital, but none testified about his mental state at the time of the offense. The jury rejected the insanity defense and returned a verdict of guilty on all counts.
At the sentencing proceeding, the prosecutor relied on the testimony of the state psychiatrists that Ake was dangerous to society. Ake had no expert witness to rebut this testimony or to introduce evidence in mitigation. The jury sentenced Ake to death on each of the two murder counts and to 500 years' imprisonment on each of the two counts of shooting with intent to kill. On appeal, the Oklahoma Court of Criminal Appeals affirmed the convictions and sentences. The Supreme Court granted certiorari.
What qualifications must a skilled witness satisfy before offering opinion testimony?
The witness must demonstrate knowledge, skill, experience, training, or education that will help the trier of fact understand the evidence or determine a fact in issue. The proponent must also show that the testimony rests on sufficient facts or data, employs reliable principles and methods, and reflects a reliable application of those methods to the case facts.
Supporting sources
May a skilled witness testify about a defendant's mental state in a criminal case?
No. In a criminal prosecution an expert may not state an opinion on whether the defendant possessed a mental state or condition that constitutes an element of the crime or a defense. Such determinations remain exclusively for the jury.
Supporting sources
When may a court appoint its own skilled witness?
On a party's motion or on its own initiative, a court may order the parties to show cause why a neutral expert should not be appointed. The court may select any expert who consents to serve and who the parties agree upon or whom the court chooses.
Supporting sources
Does reliance on data generated by a non-testifying laboratory violate the Confrontation Clause?
Not necessarily. An expert may rely on a DNA profile produced by an outside laboratory when the profile is used only to explain the basis of the expert's independent opinion and is not offered for its truth, provided the report was not prepared primarily to accuse a targeted individual.
Supporting sources
32 N.J. 358, 161 A.2d 69 (1960)
…for their own consumption or use. Makers and manufacturers know this and advertise and market their products on that assumption; witness, the “family” car, the baby foods, etc. The limitations of privity in contracts for the sale of goods developed their place in the law when marketing conditions were simple, when maker…