An appropriate evaluation of facts is often impossible without the intelligent application of technical, specialized or scientific knowledge and experience. The most widely used source of such knowledge is the expert witness. Testimony should state the facts deduced from witness’s use of his/her senses. Thus, an expert witness is believed to have specialized knowledge and expertise in a particular subject, enough that others can legally and officially rely on his/her specialized opinion about a fact or evidence.
The qualifications of expert witnesses are carefully scrutinized by courts. Besides, the experts have high responsibilities, especially in capital trials, so perjury by an expert witness becomes a severely punished crime. In the United States, the experts must satisfy the Federal Rule of Evidence 702 (FRE), according to which: “A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if: (a) the expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue; (b) the testimony is based on sufficient facts or data; (c) the testimony is the product of reliable principles and methods; and (d) the expert has reliably applied the principles and methods to the facts of the case.” Therefore, the expert witnesses are viewed in a wide sense, not only as physicists, architects, physicians, and chemists, but also as the large group called “skilled” witnesses, for instance, landowners testifying to land values or bankers.
Generally, expert testimony plays a regulatory role in complex product liability cases and mass tort. Thereby, the Frye and Daubert standards of admissibility became the subject of numerous commentaries, articles and critics, with some debating relative advantages and disadvantages. In spite of the fact that each represents a certain standard of admissibility, there are two main distinctions between the competences which are applied by both of these standards. The first concerns what body makes the call on the science. The second deals with the evidence to which these standards apply. As far as the Frye test is concerned, the trial judges are charged with assessing if such testimony is “generally accepted” in the appropriate scientific community. In the Daubert standard, judges performing their “gate-keeping” role are assessing the reliability of any expert testimony. Consequently, the Daubert test extends to all types of expert evidence, whereas in most Frye jurisdictions, types of expert testimony are limited to scientific one only. Emily C. Baker and Mary E. Desmond (2012) have noted: “The distinctions between Daubert and Frye logically suggest that the adoption of one or the other should make some difference in practice.” However, regardless of jurisdiction, both Daubert and Frye tests, if scrupulously applied, have the ability to be powerful tools in eliminating or limiting an opponent’s expert.
Those who prefer more tolerant standards of admissibility for expert evidence usually criticize the Daubert test stating that judges are not sufficiently competent to conduct rigorous evaluations of complex technical and scientific evidence. Nevertheless, Martin C. Calhoun (2008) has observed: “The track record of federal judges applying the Daubert standard over the last fifteen years shows that they can usually learn enough about the science to reach an informed decision about whether an expert’s testimony is based on reliable scientific methods and has a valid scientific connection to the inquiry at issue.” In fact, the communities of judges and scientists have a common interest nowadays: the search for truth. Thus, we are experiencing the so called twin revolution – in technology and science and in social expectations. A lot of present regulations and lawmaking derive from progress in science and technology. The courts, reflecting society, are confronting the influence of this progress, including its implications for the laws of privacy, liberty and property. In my opinion, judges have a special obligation to bridge the gap between these “two cultures”, cooperating with scientists for mutual understanding, combining the scientific and law knowledge and experience, so that differences that today are able to distort the search for truth can instead serve to guide it. Therefore, the Daubert test is likely to be more reliable as it is based on sufficient facts or data; it is the product of reliable principles; it uses the methods which rate of error may be known; and it represents a reliable application of these methods and principles to the facts of the case. Thus, it is not surprising that the majority of states today have adopted the Daubert test.
Actually, it has always been the function of the court to decide the admissibility of evidence since the very beginning of modern jurisprudence. Thereby, when examining the relevancy and admissibility of the proposed evidence, the court must guarantee that it is reliable, which means that it is not based on speculation, conjecture, hypothesis, or assumption. Proof of this requirement can be found through the Evidence Code. According to Richard J. Finn (2011) “not all cases can be proven by personal eyewitness accounts”. Consequently, the Code and the case law recognize different kinds of evidence that exist outside of this parameter. It means that there are various exceptions that permit, under appropriate conditions, the admissibility of the particular evidence. For instance, the Evidence Code determines and describes the hearsay rule and its exceptions. This part of the Evidence Code emphasizes the criteria of trustworthiness and reliability integral to any decision made by the trial court concerning the admissibility of testimony. Accordingly, these exceptions acknowledge that, under certain conditions, the out-of-court statements which are introduced to prove the truth of the matter affirmed, establish competent testimony because there exists a real foundation for its veracity and credence. Therefore, these very considerations are applicable to the expert opinion testimony.
Thus, the increased use of expert testimony and the corresponding growth in complexity of scientific studies on which experts rely heighten the necessity of guidance concerning the trail courts’ capability to regulate and percolate this testimony and limit the parties to presenting to a jury only that expert testimony which has a proper foundation. Thereto, the Evidence Code establishes the foundational requirements to offering the expert testimony and determines whether trial courts have the jurisdiction to assess the adequacy of the expert’s opinion and expert’s testimony. Furthermore, the Frye and Daubert standards of admissibility serve to filter the expert testimony in order to ensure its reliability.