Federal Rule 703
and like state rules of evidence:
THE basis OF THE OPINION. 

Here are a few quick notes to remember about the the law of presenting an expert's opinion under Federal Rule of Evidence 703 and similar state evidence rules. 

"Federal Rule 703. Bases of Opinion Testimony by Experts. The facts or data in the particular case upon which an expert bases an opinion or inference may be those perceived by or made known to the expert at or before the hearing. If of a type reasonably relied upon by experts in the particular field in forming opinions or inferences upon the subject, the facts or data need not be admissible in evidence."

The Federal Advisory Committee Notes at the time of adoption of this Rule is important. It reads, in part:

Facts or data upon which expert opinions are based may, under the rule, be derived from three possible sources. The first is the firsthand observation of the witness, with opinions based thereon traditionally allowed. A treating physician affords an example. Rheingold, The Basis of Medical Testimony, 15 Vand.L.Rev. 473, 489 (1962). Whether he must first relate his observations is treated in Rule 705 . The second source, presentation at the trial, also reflects existing practice. The technique may be the familiar hypothetical question or having the expert attend the trial and hear the testimony establishing the facts. Problems of determining what testimony the expert relied upon, when the latter technique is employed and the testimony is in conflict, may be resolved by resort to Rule 705 . 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 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. Rheingold, supra, at 531; McCormick § 15. A similar provision is California Evidence Code § 801(b). . . . .

In North Dakota, Evidence Rule 703 was proposed by the North Dakota State Bar Procedure Committee, of which Leonard Bucklin was chairman at the time.  The Official Comment suggested by the Committee, and adopted by the Court at the adoption of the rule, states, in part:

"Rule 703 is an adoption of Rule 703 of the Federal Rules of Evidence."  Similar statements are found in the rule adoption of many states.  Thus the federal decisions on the rule are persuasive to the state court.

In North Dakota, the Official comment notes a previous North Dakota case with approval, pointing out that 

"The import of the Court's decision [in Minot Sand & Gravel v. Hjelle, 231 NW2d 716 (ND 1975) was that the basis for an opinion need not be proved by admissible evidence...."

Note that under Rule 703, the judge decides whether the underlying facts may be used and whether the opinion may be admitted.

In taking depositions, attorneys should note that if you have to use the deposition at trial, you want to have the proper foundation in the record.  Especially if you agree to reserve all objections except those that go to the form of the question, you may have problems at trial.  If the exert witness is not available at the time of trial, and you are forced to use her deposition, you may find the judge ruling that there is no sufficient foundation in the deposition for the use of the testimony.

Therefore, you should always consider asking some questions of your own expert at the deposition that the other side takes of your expert.  You should have the "backup" of a deposition that you can use in an emergency if suddenly your expert is not available at trial time.

When asked to state an opinion regarding a defendant's negligence, the witness must be provided with the proper legal standard as a predicate.  Where the expert witness received the correct legal definition of negligence and gross negligence before expressing his opinions the trial court does not err in admitting the testimony.  Pittsburg Corning Corp. v. Walters, 1 SW3rd 759, 777 (Corpus Christ 1999, no pet.).