Rule 703 Basis of Opinion Testimony by Experts

Rule 703 follows the Federal Rule. For the most part it works no change in existing law, but it does make one break with the common law in expanding the category of permissible bases for an expert opinion. Under the rule, expert opinions may be based upon facts or data derived from three possible sources. The first is the firsthand observation of the witness; opinions based thereon are traditionally allowed at common law. For example, a treating physician whose opinion is based on firsthand sense impressions may use these impressions as the basis of an expert opinion. Rheingold, The Basis of Medical Testimony, 15 Vand. L. Rev. 473, 480 (1962). Whether he must first relate his observations is treated in Rule 705. The second source, presentation at trial, also reflects existing practice. Generally the expert can be informed of facts of trial in one of two ways: counsel may pose the familiar hypothetical question grounded in evidence offered to the trier of fact, or counsel may have the expert attend the trial and hear the testimony establishing the facts. In cases of conflicting testimony the hypothetical question will be the appropriate technique, as the expert should not be put in the position of deciding questions of witness credibility. When the expert purports to base his opinion on testimony offered in court, Rule 705 will provide a means of discovering whether the expert is assuming the truth of certain disputed facts. As long as the expert’s hypothesis is clarified for the trier of fact, the hybrid techniques is acceptable. The third source contemplated by the rule consists of presentation of data to the expert outside of court and other than by his own perception. In this respect the rule is designed to broaden the basis for expert opinion, in accordance with the belief that when an expert is deemed skilled enough to assist the trier of fact, the expert should be allowed to utilize the tools that he normally uses to practice his skills outside of the court. Thus, a physician in his own practice bases his diagnosis on general information obtained from medical journals and treatises and on information about the patient from numerous sources and of considerable variety, including statements by patients and relatives, reports and opinions from nurses, technicians and other doctors, hospital records, and x-rays. Some of these sources would be inadmissible in evidence; most of them are admissible, but only with the expenditure of substantial time in producing and examining various authenticating witnesses. The physician makes life-and-death decisions in reliance upon them. His validation, expertly performed and subject to cross-examination, ought to suffice for judicial purposes. Rheingold, supra, at 531. McCormick (2d ed.) § 15. The rule may be most beneficial in the examination of psychiatrists, who may often rely on data that is technically hearsay. Rule 705 controls the admissibility of facts or data not in evidence but relied upon by an expert. The rule also offers a more satisfactory basis for ruling upon the admissibility of public opinion poll evidence. If an expert pollster is called to testify, the court will focus on the validity of the techniques employed by the pollster, rather than on relatively fruitless inquiries into whether hearsay is involved. There are two major aims accomplished by providing that an expert may base an opinion on inference upon facts or data whether or not admissible in evidence if the facts or data are of a type reasonably relied upon by experts in the expert’s particular field. First, it prevents experts from explicitly relying upon facts unless these facts are of a type reasonably relied upon by similar experts. Second, it has the effect of excluding altogether some experts who would appear to qualify under Rule 702. If an expert cannot ground an opinion in facts or data “reasonably relied upon,” the opinion or inference as well as the facts and data must be excluded. Thus, some scientific or expert evidence that would not be excluded on relevance grounds will be excluded by Rule 703. While a consensus of all experts in the field that a particular test is failsafe is unnecessary, the court must be convinced that the data is a type on which those in the field would reasonably rely. The rule attempts to chart a path between the rigid approach of Frye v. United States, 293 F. 1013 (D.C. Cir. 1923) (“the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field to which it belongs”) and the minimal relevance approach of Rule 401. Even though Rule 403 might be deemed sufficient protection against the dangers of relatively untested evidence, Rule 703 is drafted so as to remind trial judges that innovative attempts to offer expert evidence may involve evidence that is superficially attractive, but which is problematic for one or more of the following reasons: 1) the party against whom the evidence is offered has had insufficient time to rebut the validity of the offered evidence, which may be the product of years of research; 2) the party against whom the evidence is offered has been unable to secure the assistance of expert help necessary to understand and attack the offered evidence; 3) while the expert evidence is plainly relevant, the rate of error associated with the technique that produced the evidence is unknown and the trier of fact is therefore unable to properly evaluate the evidence; 4) the expert evidence is the subject of great controversy among the nation’s experts and it would be inappropriate for a court or jury to resolve the controversy in any particular case. See, e.g., People v. Kelly, 549 P.2d 1240 (Cal. 1976) (rejecting voiceprint evidence). In most instances when a new technique is utilized, witnesses other than the creator of the technique will be needed to satisfy the “reasonable reliance” requirement. If the new technique is closely related to one already accepted by the courts, less foundation proof will be required. EV