An expert witness is an individual with either specialized skills, knowledge, or training who testifies for the defense or prosecution. Expert testimonies are complex and technical facts presented to the court system when there is no expert knowledge in a court case. Expert testimony is different from other types of testimony (Freckelton, 1996). Expert witnesses cannot be compelled to testify. Besides, expert witnesses are compensated for the services provided.
Expert witnesses can be professional witnesses who have perfected their performance in the court through rehearsals to present their evidence and accomplish the optimal effect. Contrary, normal witnesses do not have incentives for presenting their testimony in favor of either side (defense or prosecution). Like the normal witness, expert witnesses take an oath to present what is true regarding the case (Robertson, & Vignaux, 1995). However, the experts have pressure to make the case favorable to the party instructing them. Due to the pressure, experts may present testimony that is either deliberately false or, though accurate, deceptive by omission.
The first case that was linked to the admissibility of expert evidence was Frye v. the United States, in 1923. In Frye, the court held that for a specific scientific testimony to be admissible as evidence, the testimony should be recognized in the scientific community. The second case was Daubert v. Merrell Dow Pharmaceuticals, in 1993. In this case, the court held that expert evidence should be based on a reliable footing and applicable to the issue at hand.
The third case was General Electric Company v. Joiner, in 1997. Joiner reinforced the authority of the judge in issues of expert testimony by providing a deferential abuse of discretion standard. The fourth case was that of Kumho Tire Co. v. Carmichael, in 1999. The Kumho case expanded the use of Daubert and Joiner guidelines to any expert evidence.
One significant standard addressing the admissibility of evidence is Evidence Rule 702. Evidence Rule 702 presents a guideline for qualifying expert witnesses and eliminating bias in expert testimony. Besides, Rule 702 expresses the need for reliability function against the design rule to balance the necessities of upholding an adversarial system and eliminating bias. The rule prevents judges from using speculations presented by experts because speculation is unreliable.
References
Freckelton, I. (1996). Court experts, assessors, and the public interest. International Journal of Law and Psychiatry, 18(2), 161-188.
Robertson, B., & Vignaux, G. A. (1995). Interpreting evidence. Butterworths, Durban: John Wiley.