The first two sentences of this rule are identical with Fed. R. Evid. 703 in its entirety. The last sentence was added to clarify the court's discretion to exclude untrustworthy opinions.
The traditional view limits the facts or data upon which an expert may base an inference or an opinion to those obtained upon firsthand knowledge or to facts of record. McCormick §14. Characteristic examples of expert testimony based upon firsthand knowledge are the testimony of a physician, based on his medical examination of an individual, of a ballistics expert, based upon his examination of a bullet, or of a handwriting analyst, based upon his study of a specimen of handwriting. The expert may become conversant with facts of record either by being present during testimony or, more characteristically, through their submission to him in the form of a hypothetical question.
Hawaii decisions appear to adhere to the limitations of the traditional rule, see State v. Davis, 53 H. 582, 499 P.2d 663 (1972); Cozine v. Hawaiian Catamaran, Ltd., 49 H. 77, 106, 412 P.2d 669, 687 (1966); Kawamoto v. Yasutake, 49 H. 42, 410 P.2d 976 (1966). In State v. Dillingham Corp., 60 H. 393, 411, 591 P.2d 1049, 1060 (1979), however, the court said:
In this jurisdiction, we have taken a liberal view toward the admission of evidence used to support an expert's opinion as to fair market value [of realty].... The factors considered and the extent of knowledge and reasoning of an otherwise qualified appraiser are matters which go to the weight rather than the competence of his testimony.
Rule 703 allows opinions based on data not admissible in evidence so long as "of a type reasonably relied upon by experts in the particular field." The Advisory Committee's Note to Fed. R. Evid. 703 points out:
[T]he rule is designed to broaden the basis for expert opinions beyond that current in many jurisdictions and to bring the judicial practice into line with the practice of the experts themselves when not in court. Thus a physician in his own practice bases his diagnosis on information 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. Most of them are admissible in evidence, 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.
McCormick agrees: "It is reasonable to assume that an expert in a science is competent to judge the reliability of statements made to him by other investigators or technicians." McCormick §15.
There are several safeguards against untrustworthy opinions. The facts or data must be established as reliable in the particular field. Therefore, concluded the Advisory Committee's Note to Fed. R. Evid. 703, a court would not be justified in "admitting in evidence the opinion of an 'accidentologist' as to the point of impact in an automobile collision based on statements of bystanders, since this requirement is not satisfied." Second, the present modification of the federal rules formulation provides expressly for exclusion at the discretion of the court. Finally, Rule 705 infra, allows the court at its discretion to require prior disclosure of facts or data upon which an opinion or inference is based.
A number of other jurisdictions have adopted a similar rule, see, e.g., Cal. Evid. Code §801(b).
