Opinion ID: 2306632
Heading Depth: 3
Heading Rank: 1

Heading: d.r.e. 702

Text: McNally does not contest Rone's qualifications. Instead he argues that Rone neither divulged the facts upon which he relied nor applied his principles reliably to the facts of the case. To admit an expert's testimony, the trial judge must comply with D.R.E. 702, which states: If scientific, technical or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training or education may testify thereto in the form of an opinion or otherwise, if (1) the testimony is based upon sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case. [20] D.R.E. 702 requires the proffered testimony to provide relevant and reliable principles and methodology. [21] This rule does not require that the conclusions derived from those principles and methods be scientifically valid. [22] When the expert's application of his principles and methodology to the facts is challenged, the trial judge must determine that the expert has a reliable basis in the knowledge and experience of [the relevant] discipline. [23] Rone explained the principles and methods that he uses when testing casings for identifiable markings. He explained that when he tested the casings in this case he found similar markings that led him to conclude that the casings came from the same gun. Obviously it would have been more persuasive if Rone could recall how he arrived at his conclusion that the markings were similar, but we require the principles and methodsnot the conclusions to be scientifically valid. [24] Thus, we cannot find plain error because Rone did explain his principles and methodology and applied those principles and methods to the facts. McNally was able to cross examine Rone on those principles and his methodology. McNally was also able to expose Rone's lack of recollection about the application of the methodology to the facts here.