The Federal Standard of Expert Testimony Reliability Before Daubert

Federal courts have tried to limit the uncertainty around novel scientific evidence by starting an evidentiary standard of reliability for scientific proof. 13 min read

Evidentiary Standard for Reliability of Novel Expert Proof

Since the early part of this century, the federal courts have attempted to limit the uncertainty surrounding novel scientific evidence by establishing an evidentiary standard of reliability for scientific proof. Frye v. U.S., 293 F. 1013 (D.C.Cir.'23), provided the standard that governed the introduction of expert evidence for more than half a century. The courts have also embraced procedures, including various forms of discovery providing for mandatory disclosure of witnesses "who may be used at trial to present evidence under Rules 702, 703, or 705," and requiring submission of written reports by expert witnesses, which give the parties and the courts greater opportunities to test the reliability of novel expert testimony.

The standard of reliability for expert testimony and the applicable procedures in federal courts in the years proceeding the landmark 1993 Daubert case had undergone significant change.

A. Frye v. U.S.

As Judge Learned Hand in "Historical and Practical Considerations Regarding Expert Testimony", 15 Harv.L.Rev. 40 (1901-02) observed at the beginning of this century, expert evidence must be reliable in order to have some "possible weight" on an issue and be admitted for consideration by a trier of fact. Absent reliability, the evidence would not be relevant to the inquiry. In Frye, the Court of Appeals considered an appeal from a trial court's refusal to admit the results of a test based on systolic blood pressure, offered to prove the truthfulness of a defendant in a murder prosecution. In an oft-quoted passage, the court crafted a standard to determine whether scientific evidence was sufficiently reliable to warrant consideration by a trier of fact:

Just when a scientific principle or discovery crosses the line between the experimental and demonstrable stages is difficult to define. Somewhere in this twilight zone the evidential forces of the principle must be recognized, and while courts will go a long way in admitting expert testimony deduced from a well-recognized scientific principle of discovery, the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs.

Frye contemplated two stages for acceptance of new science.

  • First, the scientific community develops a theory and determines its reliability using scientific method. This stage required experimentation with the new science's methodology and publication of the results for scrutiny and approval by the scientific community.
  • Second, once the new science became "demonstrable," based on acceptance in the scientific community, the court could permit its use as evidence in the courtroom. Without explanation, the court of appeals chose "general acceptance" in the relevant scientific community as the standard for governing the admission of novel scientific evidence.

Under Frye, the party proffering novel scientific evidence must show general acceptance by offering scientific publications, judicial decisions, evidence of practical use, or testimony by scientists on their peers' position regarding the evidence in question. Many courts, faced with determining the admissibility of a wide array of scientific evidence, favored the Frye standard. Often, new scientific evidence failed to survive this demanding standard. For example, McCormick on Evidence reports:

Polygraphy, graphology, hypnotic and drug induced testimony, voice stress analysis, voice spectrograms, ion microprobe mass spectroscopy, infrared sensing of aircraft, retesting of breath samples for alcohol content, psychological profiles of battered women, and child abusers, post traumatic stress disorder as indicating rape, astronomical calculations, and blood group typing, all have fallen prey to [Frye's] influence.