Many experts present evidence that is fact and does not require the expert to give an opinion on those facts in the context of the case. In those circumstances, it is not necessary to overcome the additional procedural obstacles in order to classify the expert as an expert, as this is no different from the evidence submitted to the Tribunal. In some systems, the court itself or the judge may call upon experts to technically assess a particular fact or act in order to give the court full knowledge of the fact or act it is evaluating. Expertise has the legal value of data collection. The results of these experts are then compared with those of the Parties` experts. This overarching test applies to all evidence and is often debated in the context of expert evidence, which otherwise meets the admissibility criteria. The first paragraph of Article 702 requires quantitative rather than qualitative analysis. The amendment requires that expert testimony be based on sufficient underlying « facts or data ». The term « data » is intended to encompass the reliable opinions of other experts. See the original note from the Advisory Committee on Section 703. The term « facts or data » is broad enough to allow an expert to rely on hypothetical facts supported by the evidence. The amendment is not intended to establish procedural requirements for the exercise of the trial court`s review function over expert testimony. See Daniel J.
Capra, The Daubert Puzzle, 38 Ga.L.Rev. 699, 766 (1998) (« Trial courts should have considerable discretion in dealing with Daubert issues; Any attempt to codify procedures is likely to result in unnecessary changes in practice and raise difficult issues for appellate consideration. The courts have shown considerable ingenuity and flexibility in dealing with challenges to expert testimony under Daubert, and it is envisaged that this will continue under the amended rule. See, for example, Cortes-Irizarry v Corporacion Insular, 111 et seq..3d 184 (1st Cir. 1997) (analysis of Daubert`s application for summary judgment); With regard to Paoli R.R. Yard PCB Litig., 35 F.3d 717, 736, 739 (3d Cir. 1994) (discussion of the use of hearings in limine); Claar v. Burlington N.R.R., 29 F.3d 499, 502–05 (9th Cir. 1994) (discussion of the technique used by the trial court to order experts to file a series of affidavits explaining the reasoning and methods underlying their conclusions).
With this decision, the judge`s opinion in Frye v. The United States set a precedent and standard by which experts would be used in the judicial system for decades. In federal courts, Frye was cited 55 times between 1948 and 1975; However, usage and application were not consistent.  One of the greatest battles that resulted from this precedent was its application to civil and criminal cases. Many courts and judges have found it difficult to interpret briefly and not arbitrarily the notion of « general acceptance » of a particular area. As of 2012, courts in nine states were still using the Frye standard when analyzing rules for government experts.  The educational witness teaches the investigator (juror or, in a trial, judge) the underlying scientific theory and the theory of instrument implementation. This witness is an expert witness who is called upon to obtain opinions on the validity of a theory and on the reliability of the instruments involved. The witness must be qualified as an expert, which may require academic qualifications or specific training. If, pursuant to this amendment, a trial court concludes that expert testimony is reliable, this does not necessarily mean that contradictory expert testimony is unreliable.
The amendment is broad enough to allow for statements that are the product of competing principles or methods in the same field. See, for example, Heller v. Shaw Industries, Inc., 167 F.3d 146, 160 (3d Cir. 1999) (expert testimony cannot be excluded simply because the expert uses one test instead of another, if both tests are accepted in the field and both produce reliable results). As the Court stated in In re Paoli R.R. Yard PCB Litigation, 35 F.3d 717, 744 (3d Cir. 1994), proponents « do not have to prove to the judge by a balance of evidence that the assessments of their experts are correct, they need only prove by a balance of evidence that their opinions are reliable. The requirement of proof of good repute is below the standard of proof of accuracy. See also Daubert v. Merrell Dow Pharmaceuticals, Inc., 43 F.3d 1311, 1318 (9th Cir. 1995) (scientific experts could testify if they could prove that the methods they used were also used by « a recognized minority of scientists in their field »); Ruiz-Troche v. Pepsi Cola, 161 F.3d 77, 85 (1st Cir. 1998) (« Daubert requires nor empowers courts of first instance to determine which of several rival scientific theories has the best provenance. »).
Nor can experts express the opinion that another witness is inherently credible or truthful; However, a suitably qualified professional may be permitted to express an opinion on the mental or psychological capacity of another person to testify truthfully. For more information, see the relevant Expert Witness entry on polygraphs, plethysmography and witness credibility, Section B.