Expert Witnesses in Arizona
In Arizona, an expert witness is a person who is allowed to give opinion testimony because they have specialized knowledge that can help the judge or jury understand the evidence or decide a disputed fact.
Rules Governing Disclosure
In Arizona civil cases, expert disclosure is governed mainly by Arizona Rule of Civil Procedure 26.1. In a Tier 3 case, a party must provide a full expert report under Rule 26.1(d)(4) for any expert who was retained or specially hired to give expert testimony. The same requirement applies to an employee of a party if that employee’s regular duties involve giving expert testimony.
In cases that are not Tier 3, a full expert report is not automatically required. However, the court may still order one if a party requests it, or if the court itself believes that a written report would help determine whether the expert’s testimony satisfies Arizona Rule of Evidence 702.
(1) Expert Witnesses Who Do Not Provide a Written Report
If an expert witness is not required to provide a written report, the disclosure must state:
(A) the expert’s name, address, and qualifications;
(B) the subject matter on which the expert is expected to testify;
(C) the substance of the facts and opinions to which the expert is expected to testify;
(D) a summary of the grounds for each opinion;
(E) a statement of the compensation to be paid for the expert’s work and testimony in the case; and
(F) a list of all other cases in which, during the previous four years, the witness testified as an expert at a hearing or trial.
(2) Expert Witnesses Who Must Provide a Written Report
If an expert is required to provide a signed written report, the report must contain:
(A) the expert’s name, address, and qualifications, including a list of all publications authored in the previous ten years;
(B) a complete statement of all opinions the expert will express and the basis and reasons for them;
(C) the facts or data considered by the expert in forming them;
(D) any exhibits that will be used to summarize or support them;
(E) identification of any publication within the scope of Arizona Rule of Evidence 803(18) on which the expert intends to rely for any opinion;
(F) a statement of the compensation to be paid for the expert’s work and testimony in the case; and
(G) a list of all other cases in which, during the previous four years, the witness testified as an expert at a hearing or trial.
Admissibility Standards
Arizona adopted a Daubert-style approach, which placed trial judges in a gatekeeping role, meaning that judges must screen expert testimony before allowing it to reach the jury.
Arizona courts ask whether the expert is qualified, whether the testimony is relevant and helpful, and whether the opinion is reliable.
Attorney–Expert Communication Protection
Rules 26(b)(3)(A) and (B) protect communications between the party's attorney and any expert witness regardless of the form of the communications, except to the extent that the communications:
(i) relate to compensation for the expert's study or testimony;
(ii) identify facts or data that the party's attorney provided and that the expert considered in forming the opinions to be expressed; or
(iii) identify assumptions that the party's attorney provided and that the expert relied on in forming the opinions to be expressed.
The dates on which the expert received facts or data from the party's attorney that the expert considered in forming the opinions to be expressed, and any portions of communications between the party's attorney and the expert that evidence those dates are discoverable.
Compensation
Arizona courts say that expert witnesses may be compensated, but the right to expert compensation depends on the nature of the testimony. A treating physician or professional witness is not automatically entitled to expert fees when testifying only about facts learned through treatment or personal involvement. However, when the witness is asked to form or provide opinions for litigation, expert compensation may be appropriate.
Limits on Number of Expert Witnesses
Arizona generally limits each side to one retained expert per issue, unless the parties agree otherwise or the court allows more for good cause. If multiple parties on the same side cannot agree on which expert to call, the court may decide which expert will testify or may allow more than one expert. In medical malpractice cases, a defendant may testify about their own standard of care in addition to calling a standard-of-care expert, but this does not automatically entitle the plaintiff to an additional expert on the same issue.
Out-of-State Expert Qualification
Arizona allows out-of-state experts. In ordinary cases, the expert must satisfy Rule 702 by showing suitable knowledge, skill, experience, training, or education. In medical malpractice cases, A.R.S. § 12-2604 specifically permits experts licensed in Arizona or another state, but they must meet Arizona’s same-specialty and recent-practice requirements.
