Because the Vocational Expert ("VE") testifies at the disability hearing and that testimony is used by the Administrative Law Judge ("ALJ") to determine whether a claimant is disabled, a standard is needed to define the specific requirements that the VE's testimony and the VE's methodology must satisfy in order to maintain the integrity of the VE's testimony.
The most wellknown example of a standard that places a check on the testimony of an expert is Rule 702, but before the adoption of Rule 702, American courts relied on the Frye standard.
- Pre-Daubert: Frye v. United States
Before implementation of Rule 702, the Frye general acceptance standard was the established standard for determining the admissibility of expert testimony. This standard required testimony from experts in relatively novel scientific fields to be closely scrutinized and ultimately ruled inadmissible if the expert's conclusions had not yet gained scientific recognition among other experts in the novel scientific field.
- Daubert v. Merrill Dow Pharmaceuticals, Inc.
In 1983, Daubert incorporated into evidentiary jurisprudence the notion that judges act as gatekeepers; this required a judge to determine whether a proffered expert opinion is both relevant and reliable to the issue being sought for admission. Daubert established that federal *381 judges cannot merely defer to a proposed expert on the ground that the expert has good credentials in a field that is atypical or complex.
Any prospective expert evidence that is not both reliable and relevant must be excluded by the gatekeeper because it is speculation rather than knowledge. Eventually, the Supreme Court expanded Daubert by declaring that gatekeepers must ensure that any and all scientific testimony is not only relevant, but reliable, and gatekeepers must apply this rule equally to all expert testimony. Under Kumho Tire Co., Ltd. v. Carmichael, courts are expected to filter the good science from the bad science and thus ensure that the proposed expert testimony is supported by appropriate validation.