Rule 701: Opinion Testimony by Lay Witnesses

If the witness is not testifying as an expert, the witness's testimony is limited to those opinions or inferences which are (a) rationally based on the perception of the witness, (b) helpful to a clear understanding of the witness's testimony or to determining a fact about a case, and (c) not based on scientific, technical or other specialized knowledge within the scope of Rule 702.

Rule 702: Testimony by Experts

If scientific, technical or other specialized knowledge will help the jury understand the evidence or determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training or education may testify and provide an opinion. The testimony must be based upon sufficient facts or data and the product of reliable principles and methods. The witness must have applied the principles and methods reliably to the facts of the case.

Rule 703: 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 facts or data can be reasonably relied on by experts in the particular field when they form opinions or inferences about the subject, the facts or data need not be admissible as evidence in order for the opinion or inference to be admissible in the courtroom. Facts or data that are inadmissible shall not be disclosed to the jury unless the court determines that their probative value in assisting the jury to evaluate the expert's opinion substantially outweighs their prejudicial effect.

Rule 704: Opinion on the Ultimate Issue

(a) Except as provided in subsection (b), admissible testimony in the form of an opinion or inference is not objectionable because it embraces an ultimate issue that will be decided by the jury.

(b) No expert witness testifying about the mental state or condition of a defendant in a criminal case may state an opinion about whether the defendant had the mental condition when committing the crime. Such ultimate issues are matters for the jurors to decide.

Rule 705: Disclosure of the Facts or Data Underlying an Expert Opinion

The expert may testify in terms of opinion or inference and give reasons for that opinion without first testifying to the underlying facts or data, unless the court requires otherwise. The expert may be required to disclose the underlying facts or data on cross-examination.

Rule 706: Court-Appointed Experts

(a) Appointment. The court may, on its own motion or on the motion of any party, enter an order to show cause why expert witnesses should not be appointed and may request all parties to submit nominations. The court may appoint any expert witnesses agreed upon by all parties and may appoint expert witnesses of its own selection. An expert witness shall not be appointed by the court unless the witness consents to act. A witness so appointed shall be informed of the witness's duties by the court in writing, a copy of which shall be filed with the clerk or at a conference in which the parties shall have the opportunity to participate. A witness so appointed shall advise the parties of his or her findings. The witness's deposition may be taken by any party, and the witness may be called to testify by the court or any party. The witness shall be subject to cross-examination by each party, including a party calling the witness to the stand.

(b) Compensation. Expert witnesses are entitled to reasonable compensation in whatever sum the court may allow. The compensation is payable from funds which may be provided by law in criminal cases and civil actions and proceedings involving just compensation under the Fifth Amendment. In other civil actions and proceedings, the compensation shall be paid by the parties in such proportion and at such time as the court directs, and thereafter charged like any other costs.

(c) Disclosure of Appointment. The court may disclose to the jury that the court appointed the expert witness.

(d) Parties' Experts of Own Selection. Nothing in this rule limits the parties from calling expert witnesses of their own selection.

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