Scientific evidence constitutes evidence that has been developed through some sort of scientific method. Usually scientific evidence is information that has been published in periodicals and tested by scientists or professionals. This scientific information is considered to be valid within the scientific community. Examples of scientific evidence include:

• DNA.
  
• Fingerprints and footprints.
  
• Fiber analysis.
  
• Hair analysis.
  
• Voice analysis and identification.
  
• Blood tests.
  
• Breath tests.
  
• Photographs.

How Scientific Evidence is Presented

Generally, scientific evidence is presented by an expert witness. Both the prosecution and defense may use experts to pontificate their points with respect to the type of scientific evidence presented. If the scientific theory presented is a well accepted and established theory, testimony by the expert may be sufficient to establish the reliability of the evidence sought to be admitted. However, if the scientific theory is not well accepted in the scientific community the proponent of the evidence may have to present additional evidence to support the admission of the scientific evidence. The court may schedule a separate hearing in which the expert is required to testify and explain the scientific method used. The purpose of the hearing is to establish the reliability of the evidence sought to be admitted by the proponent.

The Daubert Standard

For a scientific expert opinion to be admissible it is required that the court find by a preponderance of the evidence that the evidence underlying the expert's opinion is scientifically valid. The Daubert standard requires that the trial court make a preliminary assessment as to whether the reasoning or methodology underlying the expert's testimony is scientifically valid and could be properly applied to the facts in the case. The Daubert standard involves the application of four elements. The elements are:

• Whether the technique has been or could be empirically tested.
  
• Whether the theory has been subject to review or publication.
  
• The potential rates of error and existence of maintenance of records.
  
• General acceptance of the theory.

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