Arizona Rules Regarding Expert Witness Depositions and Interrogatories
Under Rule 26(b)(4)(A) of the Arizona Rules of Civil Procedure, a party can depose any expert who might testify at trial, and under Rule 30(d), depositions generally cannot exceed four hours. See also State ex rel. Willey v. Whitman, 370 P.2d 273, 277 (Ariz. 1962) (explaining that the deposition of an expert expected to be called at trial “may be taken under the same circumstances as any other witness.”).
Under Rule 26(b)(4)(B), a party can discover the facts and opinions of experts hired in preparation for, but not expected to be used at, trial only upon a showing of exceptional circumstances such that it would be impractical for the party seeking discovery to acquire the information held by such experts through other means. If the court finds that this standard has been met, discovery can take place by either interrogatory or deposition.
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Arizona Expert Witness Reports and Disclosures Rules
Under Rule 26.1(a)(6) of the Arizona Rules of Civil Procedure, each party to a litigation must disclose to the other the name address of each expert it expects to call at trial, the facts and opinions to which they will testify, the basis for those opinions, the qualifications of the experts, and the custodian and location of any reports prepared by the experts. Rule 26.1(b)(2) further requires that the parties shall seasonably amend or supplement these disclosures upon discovery of any new information. Additionally, under Rule 705 of the Arizona Rules of Evidence, experts can be required to disclose the facts and data underlying their opinions on cross-examination.
Rules Regarding Lawyer-Expert Communications, Draft Expert Witness Reports, Expert Witness Notes, Etc. in Arizona
Under Rule 26(b)(3) of the Arizona Rules of Civil Procedure, a court may order disclosure of materials prepared by a party’s representative in preparation for trial only upon a showing of substantial need by the opposing party, such that the party would be unable to acquire the substantial equivalent of those materials without undue hardship. In making such an order, the court must protect against disclosure of the attorney’s mental impressions, conclusions, opinions, or legal theories relating to the case. The extent to which this protection applies to lawyer-expert communications, reports, etc. depends on the role for which the expert has been retained. Arizona cases delineate different levels of protection for experts retained for consultation in preparation for trial and experts retained to testify at trial. On one side, communications between attorneys and experts retained solely for consultation purposes in preparation for trial are fully protected from discovery. Granger v. Wisner, 656 P.2d 1238, 1242 (Ariz. 1982) (“The rule has been interpreted to prevent even the discovery of the identity of the non-testimonial expert.”); Emergency Care Dynamics v. Superior Court, 932 P.2d 297, 298 (Ariz. Ct. App. 1997) (“If Petitioners had engaged [the expert] as a consulting, not testimonial, expert, . . . Petitioners’ lawyers could protect their communications with [the expert] under Rule 26(b)(4)(B) . . . .”); see also State ex rel. Corbin v. Ybarra, 777 P.2d 686, 691 (Ariz. 1989) (explaining that reports from experts are protected attorney work product when those experts will not be presented as witnesses at trial). On the other hand, for experts retained to provide testimony at trial, Arizona courts follow the rule developed in Federal courts that “written and oral communications from a lawyer to an expert that are related to matters about which the expert will offer testimony are discoverable, even when those communications otherwise would be deemed opinion work product.” Emergency Care Dynamics, 932 P.2d at 300 (quoting Intermedics, Inc. v. Ventritex, Inc., 139 F.R.D. 384, 387 (N.D. Cal. 1991)); see also Para v. Anderson, 290 P.3d 1214, 1216 (Ariz. Ct. App. 2012) (“A party that elects to present its consulting expert as a testifying witness waives the privileges and discovery protections that would otherwise apply to the expert.”).
Other Expert Witness Rules in Arizona
Under Rule 26(b)(4)(D) of the Arizona Rules of Civil Procedure, in all cases each party is generally limited to one independent expert on each issue. Additionally, in medical malpractice cases, in addition to the one independent expert, each party can call one standard of care expert.
 Although Ybarra was a criminal case, it was cited approvingly in Emergency Care Dynamics, which was a civil case.