The Frye Rule
The traditional standard for the admission of medical testimony was established in the Frye case, which involved the appeal of a criminal defendant who was convicted based on a precursor to the lie detector. This machine measured changes in the systolic blood pressure and the operator of the machine would then correlate these changes with the defendant’s truthfulness. The defendant argued that this was an unfounded technique that was not recognized by scientists in the field. The Court agreed, and established this standard:
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 force 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 or 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 v. United States, 293 F. 1013, 1014 (App. D.C. Dec. 03, 1923).]
The Frye rule became the standard for federal and state courts evaluating expert testimony. Before an expert witness could testify, the judge would have to determine if the testimony met the Frye test and, if it did, if the witness was properly qualified to be an expert. For example, in a medical malpractice case against a surgeon for negligence in the performance of a surgical procedure, the plaintiff would have to have an expert who was well versed in surgery and knowledgeable in the procedures at issue. If the plaintiff tried to use a pharmacist to testify, the judge would exclude the testimony because a pharmacist does not have the training and expertise of a surgeon. If the plaintiff had a surgeon as an expert, but the surgeon wants to testify that the defendant should have used a surgical procedure that no one but the plaintiff’s expert uses, the judge would exclude the testimony because it was not generally accepted.
The Frye rule has several shortcomings. General acceptability excludes many new discoveries that have not had time to become generally accepted. General acceptability is hard to establish for narrow areas of inquiry where there may only be a few experts. It is also problematic if the plaintiff is arguing that what is generally accepted is not true. In contest to Frye, the tort law recognizes that there are situations where what is generally accepted is not proper behavior. [The T.J. Hooper, 60 F.2d 737 (C.C.A.2 1932).] Finally, the Frye rule proved difficult to administer, encouraging judges to allow broad latitude for the admission of questionable evidence.