a) Expert Witnesses

1. 1) Testimony by Expert Witnesses

   1. A) If scientific, technical or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training or education may testify in the form of an opinion or otherwise.
   2. B) When an expert witness testifies to an opinion based on a new or novel scientific methodology or principle, the proponent of the opinion has the burden of showing the methodology or scientific principle on which the opinion is based is sufficiently established to have gained general acceptance in the particular field in which it belongs. (Il. Mil. R. Evid. 702)

2. 2) Bases of an Expert's Opinion Testimony

   1. A) The facts or date 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.
   2. B) 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. (Il. Mil. R. Evid. 703)

3. 3) Opinion on an Ultimate Issue

   Testimony in the form of an opinion or inference otherwise admissible is not objectionable because it embraces an ultimate issue to be decided by the trier of fact. (Il. Mil. R. Evid. 704)

4. 4) Disclosing the Facts or Data Underlying an Expert's Opinion

   1. A) The expert may testify in terms of opinion or inference and give the expert's reason for the opinion or reference without prior disclosure of the underlying facts or data, unless the military judge requires otherwise.
   2. B) The expert may, in any event, be required to disclose the underlying facts or data on cross-examination. (Il. Mil. R. Evid. 705)

5) Court-Appointed Expert Witnesses

1. A) Appointment and Compensation. The trial counsel, the defense counsel, and the court-martial have equal opportunity to obtain expert witnesses under Code Section 46.
2. B) Disclosure of Employment. In the exercise of discretion, the military judge may authorize disclosure to the members of the fact that the military judge called an expert witness.
3. C) Accused's Experts of Own Selection. Nothing in this subsection (a)(5) limits the accused in calling expert witnesses of the accused's own selection and at the accused's own expense. (Il. Mil. R. Evid. 706)

b) Polygraph Examinations

1. 1) Notwithstanding any other provision of law, the results of a polygraph examination, the opinion of a polygraph examiner, or any reference to an offer to take, failure to take, or taking of a polygraph examination, shall not be admitted into evidence.
2. 2) Nothing in this subsection (b) is intended to exclude from evidence statements made during a polygraph examination that are otherwise admissible. (Il. Mil. R. Evid. 707)