Maryland Rule 5-702 - Interpretation
In Sippio v. State, 350 Md. 633, 714 A.2d 864 (1998), the Court of Appeals explained:
According to Md. Rule 5-702, which codified the modern common-law rule regarding expert testimony, a trial court must determine whether the evidence to be presented is a proper subject of expert testimony.
The inquiry turns on whether the trier of fact will receive appreciable help from the expert testimony in order to understand the evidence or to determine a fact in issue.
The trial court need not consider whether the trier of fact could possibly decide the issue without the expert testimony.
Nor must the subject of the expert testimony be so far beyond the level of skill and comprehension of the average layperson that the trier of fact would have no understanding of the subject matter without the expert's testimony.
In ascertaining whether expert testimony will be helpful to the trier of fact, a trial court must instead determine whether certain requirements have been satisfied:
(1) the proposed witness must be qualified to testify as an expert;
(2) the subject matter about which the witness will testify must be appropriate for expert testimony;
(3) there must be a legally sufficient factual basis to support the expert's testimony. (Id. at 649.)