§24.18 KEY POINTS

• Jurisdiction: United States

§24.18. KEY POINTS

The use of expert testimony raises two threshold issues. First, is the proffered testimony a proper subject matter for expert testimony? If the answer is "yes," the next question follows: Is this witness qualified in this subject matter? There is typically no requirement that an expert be called as a witness on a particular issue. Malpractice cases, however, frequently require expert testimony to establish the standard of care.

Subject Matter Requirement

Expert testimony is bounded on one side by the unreliable and on the other side by the commonplace. Thus, courts developed one standard for instances where expertise is not needed — i.e., the commonplace — and another standard for judging when the testimony is too unreliable.

Commonplace. The standard adopted by Rule 702 — whether expert testimony "will help the trier of fact to understand the evidence or to determine a fact in issue" — is a more liberal formulation of the subject matter requirement than that found in many common-law opinions, which phrased the requirement as whether the subject was beyond the ken of lay persons. In short, Rule 702 rejects "necessity" as the appropriate test.

Unreliable. At least four different approaches can be gleaned from the cases: (1) the Frye "general acceptance" test, (2) a relevancy approach, (3) the Supreme Court's reliability approach, as set forth in Daubert v. Merrell Dow Pharm., Inc., and (4) other reliability tests.

Frye test. Although Frye is no longer the majority rule, it is still followed in several jurisdictions, including California, Florida, Illinois, Maryland, Minnesota, New Jersey, New York, Pennsylvania, and Washington. Because these are populous states and most crimes are prosecuted in state courts, Frye remains an important test.

Relevancy approach. In his 1954 text, McCormick argued that a special test, such as general acceptance, was not needed and that the traditional evidentiary rules on relevancy and expert testimony should be applied in this context. In effect, qualifying the expert presumptively qualifies the technique used by that expert. This is the most lax standard, and only a few states presently follow it. This approach was implicitly rejected by the Supreme Court in Daubert, which requires the trial judge to determine reliability in addition to relevancy.

Reliability test. In Daubert, the Supreme Court rejected the Frye test and substituted a reliability approach. In performing the Daubert "gatekeeping function,"...