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Scientific Evidence

Relevancy Test

One alternative approach to Frye is to treat scientific evidence in the same way as other evidence, weighing its probative value against countervailing dangers and considerations. Charles McCormick, a noted evidence scholar, advocated this position. In his 1954 text, he wrote that "Any relevant conclusions which are supported by a qualified expert witness should be received unless there are other reasons for exclusion. Particularly, its probative value may be overborne by the familiar dangers of prejudicing or misleading the jury, unfair surprise and undue consumption of time" (pp. 363–364).

In practice, however, the relevancy test affords inadequate assurance of the reliability of scientific evidence; this test often means that qualifying the expert automatically renders testimony about the technique admissible. Even if the expert is qualified, the expert may be relying on a bogus theory or technique. "The major flaw in the relevancy analysis . . . is its failure to recognize the distinctive problems of scientific evidence. . . . [T]he judge frequently is forced to defer to an expert, thereby permitting admissibility based on the views of a single individual in some cases" (Giannelli, 1980, p. 1250).

Barefoot v. Estelle.Barefoot v. Estelle, 463 U.S. 880 (1983), a capital murder case decided by the Supreme Court in 1983, illustrates the weakness of the relevancy approach even though the case was decided on constitutional, rather than evidentiary, grounds. In the penalty phase, the prosecution offered psychiatric testimony concerning Barefoot's future dangerousness, a qualifying factor under the Texas death penalty statute. One psychiatrist, Dr. James Grigson, without ever examining Barefoot, testified that there was a "'one hundred percent and absolute' chance that Barefoot would commit future acts of criminal violence" (463 U.S. at 919). Barefoot challenged the admission of this evidence on constitutional grounds due to its unreliability.

In an amicus ("friend of the court") brief, the American Psychiatric Association (APA) stated that the "large body of research in this area indicates that, even under the best of conditions, psychiatric predictions of long-term future dangerousness are wrong in at least two out of every three cases" (p. 9). In a later passage, the brief noted that the "unreliability of psychiatric predictions of long term future dangerousness is by now an established fact within the profession" (p. 12). A substantial body of research supported the APA position.

Nevertheless, the Court rejected Barefoot's argument. According to the Court, "[n]either petitioner nor the [APA] suggests that psychiatrists are always wrong with respect to future dangerousness, only most of the time" (p. 901). In one passage the Court virtually adopts McCormick's relevancy approach. As a result, the Barefoot Court admitted evidence "at the brink of quackery" (Dix, p. 172). Justice Blackmun, who later authored the Daubert opinion, dissented. He noted that "[i]n the present state of psychiatric knowledge, this is too much for me. One may accept this in a routine lawsuit for money damages, but when a person's life is at stake . . . a requirement of greater reliability should prevail. In a capital case, the specious testimony of a psychiatrist, colored in the eyes of an impressionable jury by the inevitable untouchability of a medical specialist's words, equates with death itself" (p. 916). Even a proponent of capital punishment believed that the execution of Thomas Barefoot on 24 October 1984 was based on "junk science." One could favor the death penalty and "yet still recoil at the thought that a junk science fringe of psychiatry . . . could decide who will be sent to the gallows" (Huber, p. 220).

Additional topics

Law Library - American Law and Legal InformationCrime and Criminal LawScientific Evidence - Contributing Factors, Novel Scientific Evidence, Frye V. United States, Relevancy Test, Reliability Test