Is an Expert Opinion Subject to the California Kelly Rule
In People v. Kelly (1976) 17 Cal.3d 24, the Supreme Court held that evidence obtained through a new scientific technique may be admitted only after its reliability is established under a three prong test.
The test requires proof: (1) the technique is generally accepted as reliable in the relevant scientific community; (2) the witness testifying about the technique and its application is a properly qualified expert on the subject; and (3) the person performing the test in a particular case used correct scientific procedures. (Kelly, supra, 17 Cal.3d at p. 30.)
The Kelly "'rule serves the salutary purpose of preventing the jury from being misled by unproven and ultimately unsound scientific methods.' " (People v. McDonald (1984) 37 Cal.3d 351, 372-373, overruled on another ground in People v. Mendoza (2000) 23 Cal.4th 896, 914.)
However, Kelly applies only to "new scientific techniques," and "'to that limited class of expert testimony which is based, in whole or part, on a technique, process, or theory which is new to science and, even more so, the law.' " (People v. Leahy (1994) 8 Cal.4th 587, 605.)
"Thus, Kelly analysis is limited to situations where it will 'forestall the jury's uncritical acceptance of scientific evidence or technology that is so foreign to everyday experience as to be unusually difficult for laypersons to evaluate. In most other instances, the jurors are permitted to rely on their own common sense and good judgment in evaluating the weight of the evidence presented to them.'" (People v. Venegas (1998) 18 Cal.4th 47, 80; People v. Mitchell (2003) 110 Cal.App.4th 772, 782-783.)
In short, absent a special or unique scientific feature unfamiliar to the jury, expert opinion is not subject to the Kelly rule.