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 in order for the opinion or inference to be admitted. Facts or data that are otherwise inadmissible shall not be disclosed to the jury by the proponent of the opinion or inference unless the court determines that their probative value in assisting the jury to evaluate the expert's opinion substantially outweighs their prejudicial effect [Amended 8-15-2013, 3ff. 10-1-2013.] Advisory Committee’s Notes Experts may acquire the facts, upon which they base their opinions and testimony, by firsthand observation. This would be exemplified by a treating physician who is called to testify. Armstead v. Smith, 434 So.2d 740 (Ala.1983); Jones v. Keith, 223 Ala. 36, 134 So. 630 (1931). However, experts historically have been exempted from the requirement of possessing firsthand knowledge; indeed, experts are the only witnesses so exempted. The common law has recognized the familiar hypothetical question as a primary source from which the expert could gain a knowledge, albeit secondhand, of the facts. Alabama Power Co. v. Robinson, 447 So.2d 148 (Ala.1983). Under Rule 703, two additional sources exist for the facts upon which the expert’s opinion may be based. First, the expert may attend the trial and there be made privy to the facts upon which his or her testimony is to be based. This means of being furnished the facts, insofar as not requiring a hypothetical question, is new to Alabama practice. See Porter v. State, 135 Ala. 51, 33 So. 694 (1903); Gunter v. State, 83 Ala. 96, 3 So. 600 (1888). Rule 703 also provides, however, that the facts may be made known to the expert outside the trial or hearing at which the expert is testifying. This includes data presented to the expert by means other than personal perception, such as through the opinions, records, or reports of others.