An expert needs to have:

  1. Proper Qualifications
  2. Proper Tocis
  3. Sufficient Basis of facts of the opinion
  4. Reliable Methods
  5. Survive 403 challenges

Who Qualifies—702

United States v. Johnson

575 F.2d 1347 (5th Cir. 1978).

The government attempted to have a witness testify that the source of the drugs were from another country (the drugs were not attainable). In an objection, the court considered whether the witness was qualified to testify about the source of the drugs. During this questioning, the witness said he had smoked the drug one 1000 times, dealt in it over 20 times, and asked to identify it over 100 times (without ever making an error). With this, the court determined he was qualified and allowed the testimony. Qualifications can come from experience or education. Here, it is within the court’s discretion to determine whether those conditions are satisfied, and the defense is still permitted to present opposite experts.

Jinro America, Inc. v. Secure Investments, Inc.

266 F.3d 993 (9th Cir. 2001).

Jinro (a Korean business) sued Secure over a business deal gone bad. Secure stated the deal was a sham and submitted an expert to testify about the poor dealings of Korean businesses. When asked about the basis of the opinion, he listed his “hobby,” office staff, and negative experiences based on the nature of his work (security). Although admitted at trial, this is not enough to establish the qualifications of an expert.

United States v. Plunk, 153 F.3d 1011 (9th Cir. 1998). An officer had been undercover for several years working on large-scale drug trafficking organizations. He was called to testify as to the lingo code to interpret some of the meanings. Is his testimony admissible? Experience is probably better than education in this sort of field, admitted.

Proper and Improper Topics of Expert Testimony—702(a) & 704

Common Knowledge

Chesebrough-Pond’s, Inc. v. Faberge, Inc., 666 F.2d 393 (9th Cir. 1982). In a trademark dispute, is it common knowledge that the words “macho” and “match” are confusingly similar? Should an expert in language be called to tell apart the differences? Not likely, the testimony is unhelpful.

Tyus v. Urban Search Management, 102 F.3d 256 (7th Cir. 1996). Housing ads used only white-models. Can an expert be called to testify on the effect this might have on African-American viewers? Trial court said no, but the 7th Circuit disagreed saying this goes towards social studies.

Rosenfeld v. Oceania Cruises, Inc. 654 F.3d 1190 (11th Cir. 2011). Rosenfeld slipped and fell on a cruise. She wanted to present an expert to testify that the tiles used by the cruise are naturally slippery based on a coefficient of friction. Can she do so? Likely.

Opinions on Law and Ultimate Issues

State v. Montgomery, 183 P.3d 267 (Wash. 2008). Montgomery had purchased supplies that are consistent with the manufacture of an illegal drug. Combined with the co-defendant’s purchases, this would be sufficient to establish the makings of the drug, but alone the purchases were not enough. Montgomery offered that his purchases were for innocent reasons. An expert testified against him and said that the material was indeed known and established to be ingredients for the drug. This testimony is not admissible because the expert is testifying as to an element of the crime.

Hygh, v. Jacobs

961 F.2d 359 (2d Cir. 1992).

Hygh accused Jacobs of excessive force in effectuating an arrest. He called an expert to the stand that provided a definition of deadly force different from the statute and said that Jacob’s actions were “totally improper.” Essentially, these statements overburdened the jury, telling them what result to reach. However, there was not reversible error because everything else said was admissible.

Opinions on Witness Credibility

Nimely v. City of New York, 414 F.3d 381 (2d Cir. 2005). In a dispute about whether the victim was shot in the back or front, the defense called a forensic witness to testify that the victim had been shot from the front. In part of his analysis, he concluded that the officer’s truthfulness was fine because otherwise it would have been such an easy lie to disprove. Was this testimony admissible? No.

United States v. Herron, 2014 WL 1871909 (E.D.N.Y.). The defense wished to call a witness to testify that rap lyrics are not designed to be expressions of truth by the artist. Is this testimony on witness credibility?

State v. Batangan

71 Haw. 552 (1990).

Bantangan was accused of raping his daughter. An expert was called to testify as to the behavior of children who suffer this form of abuse. He testified that the child was believable that the defendant had committed the crime. To this the defense objected. The material should not have been admissible because his testimony did nothing more to help the jury than they could have deduced by themselves. The expert could testify to the behavior, but not to the credibility of the accusation.

Basis of Expert Opinion Testimony—702(b), 703, & 705

In re Melton

597 A.2d 892 (D.C. 1991).

Melton was considered to likely injury himself or others by expert testimony. Could these experts rely on the mother’s account that Melton had hit her? Yes, to an extent.

United States v. Kantengwa, 781 F.3d 545 (1st Cir. 2015). Kantengua was convicted for perjury and obstruction of justice related to a Rwandan genocide. She testified that there was no roadblock outside the hotel where she was staying. A political science testified that there was a roadblock, based on information obtained form 25 interviews, letters, and minutes of the government, etc. Is this a proper basis for the testimony? The court needs to conduct a 104(a) hearing to assess reliability, but ultimately the answer is yes.

Ricciardi v. Children’s Hospital Medical Center, 811 F.2d 18 (1st Cir. 1987). Should a doctor’s testimony be admitted based on the testimony of another doctor and his note (doctor’s identity is unknown). The testimony is only admissible if experts in the field generally rely on notes of this kind.

Assessing Reliability of Scientific Testimony

Frye v. United States

293 Fed. 1013 (D.C. App. 1923).

Frye was subject to a blood pressure deception test, new scientific test that was transforming from experimental to recognized scientific principles. Was the use of the machine and the testimony associated with it, admissible against the defendant? It was admissible if there was a “general acceptance” within the field.

Daubert v. Merrill Dow Pharmaceuticals, Inc.

509 U.S. 579 (1993).

Experts were called to question whether Bendectin could cause birth defects in humans. The defendants showed that the drug could not while the plaintiffs presented new studies that had not been peer reviewed to say that they could. At trial, this was not allowed. Even so, this is a presentation of “scientific” evidence that was not scientific because it still lacked a scientific founding. Based on a 104(a) hearing determining admissibility, the court should determine whether the evidence is scientific or not. Reversed and remanded.

Assessing Reliability of Non-Scientific Testimony

Kumho Tire Company v. Carmichael

526 U.S. 137 (1999).

An expert testified how a tire had exploded. Although his analysis was not scientific, it was technical. Does the court need to apply a Daubert analysis for technical testimony to test reliability. Yes. So, the court should ask if there are standard practices to test the theory, whether there was peer review of those practices, etc. but it still has the flexibility to determine what method makes material more reliable.

Ayers v. Robinson, 887 F. Supp. 1049 (N.D. Ill. 1995). An economist had developed a method on how to value human life in dollar amounts by lost earning capacity. Can Ayers admit this testimony to inform the jury how a calculation could be done and award her $2 million dollars for the life of her son? Maybe. Ultimately this is likely to be inadmissible based on a 403 analysis.

Tardif v. City of New York

344 F. Supp. 3d 579 (S.D.N.Y. 2018).

When evaluating expert witnesses, the court considers the qualifications, reliability, and helpfulness of the witness.

Tardif was involved in protests within New York on several occasions. She is suing the city and officers for injuries she sustained and specifically for PTSD related to the protests. She presented an expert to testify that she has PTSD, and it was caused by the officer’s actions at the protests. Although the expert can testify as to PTSD, he is not permitted to discuss causation. The state also produced an expert on PTSD. This expert is considered reliable and helpful and so could testify that Tardif did not suffer from PTSD.

How could the court determine that both the experts were reliable beyond a preponderance of the evidence, when the obtained opposite results?

Ryan v. State, 988 P.2d 46 (Wyo. 1999). Keri Ryan was found shot to death in her home. Evidence showed that she suffered from battered wife syndrome, abused by her husband Ryan. Eventually, she left Ryan and started dating another man. At trial, the state wished to offer evidence that this period of time is called “separation violence” a phase where the victim is in the most danger because the abusing spouse can’t handle the idea of the separation. Could this testimony be offered as the logical extension of battered wife syndrome?


The content contained in this article may contain inaccuracies and is not intended to reflect the opinions, views, beliefs, or practices of any academic professor or publication. Instead, this content is a reflection on the author’s understanding of the law and legal practices.