What is scientific evidence? According to Black's Law Dictionary, scientific evidence is "fact or opinion evidence that purports to draw on specialized knowledge of a science or to rely on scientific principles for its evidentiary value". Evidence, Black's Law Dictionary (10th ed. 2014).
Because scientific evidence is beyond the realm of judges’ and jurors’ everyday experiences, the prosecution and defense use expert witnesses to introduce scientific evidence at trial. The Daubert Test is a method that federal district courts use to determine whether expert testimony is admissible under Federal Rule of Evidence 702, which generally requires that expert testimony consist of scientific, technical, or other specialized knowledge that will assist the fact-finder in understanding the evidence or determining a fact in issue. See Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579, 113 S.Ct. 2786 (1993).
During a pretrial Daubert hearing, a court will review the evidence outside the jury's presence. The proponent must show that the expert's underlying reasoning or methodology, and its application to the facts, are scientifically valid. In ruling on admissibility, the court considers the following factors:
In Virginia, the standard for admissibility of scientific evidence comes from Spencer v. Commonwealth, 393 S.E. 2d 609, 240 Va. 78 (2008). In Spencer, the Virginia Supreme Court held that when scientific evidence is offered, a court "must make a threshold finding of fact with respect to the reliability of the scientific method offered," unless: 1) it is a type of evidence "so familiar and accepted as to require no foundation to establish the fundamental reliability of the system, such as fingerprint analysis;" 2) it is so unreliable "that the considerations requiring its exclusion have ripened into rules of law, such as "lie-detector" tests;" or 3) its admission is required or regulated by statute, such as blood-alcohol concentration test results. The court will usually have to rely on expert testimony to make the threshold finding of fact; if there is a conflict, the finding will not be disturbed on appeal as long as the trial court's finding is supported by credible evidence. Even in the case where there is a dispute about the reliability of scientific evidence, the court may, in its discretion and if it determines that there is a sufficient foundation, admit the evidence "with appropriate instructions to the jury to consider the disputed reliability of the evidence in determining its credibility and weight." Scientific unanimity is not required, and the court has wide discretion to determine whether the evidence is reliable enough to be put before the jury. Spencer, 393 S.E.2d at 621.
Use this guide as a tool for locating the following:
Reference Sources - links to catalog records of various forensic encyclopedias and scientific dictionaries
Treatises - links to catalog records for books on scientific evidence and forensics; also links to publications available through Westlaw, Lexis Advance, and Bloomberg
Databases - links to databases containing scientific, social science, and legal scholarly articles as well as statistics databases
Case Law - links to sources for locating case law on scientific evidence topics
Drafting Litigation Documents - links to sources of practice notes, litigation document templates and examples
Other Sources -- links to research guides and other helpful sources