Missouri Rules Regarding Expert Witness Depositions and Interrogatories 

Under Rule 56.01(b)(4)(B) of the Missouri Rules of Civil Procedure, a party may depose opposing experts to discover the facts and opinions to which the expert is expected to testify. The Missouri Rules to do not specify a time limit for depositions, but Rule 57.03(b)(2) provides that the court may increase or decrease the time allowed for deposition upon a showing of cause. As the language of Rule 56.01(b)(4)(B) indicates, generally only experts expected to testify at trial may be subject to deposition. Note, though, that when a party retains an expert to examine an accident, the expert may become a witness to the accident, which may render the observations of the expert discoverable no matter whether the expert will be called to testify at trial. See State ex rel. Mo. Pub. Serv. Co. v. Elliott, 434 S.W.2d 532, 537-38 (Mo. 1968).

Experts generally may not be subject to interrogatories in Missouri, as they are only served on the parties. As discussed in the following section, though, these interrogatories can require disclosures about experts and, accordingly, expert participation in responding to certain interrogatories may be beneficial. 

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Missouri Expert Witness Reports and Disclosures Rules 

Rule 56.01(b)(4)(a) of the Missouri Rules of Civil Procedure provides that a party in interrogatories may require its opponent to identify, for each expert the opponent expects to call to testify at trial, the expert’s name, address, occupation, place of employment, and qualifications to give an opinion. Alternatively, if such information is available on the expert’s curriculum vitae, that curriculum vitae may be attached to the interrogatory answers as a full response to the interrogatory. Further, the interrogatories can also require the opponent to disclose the general nature of the subject matter of the expert’s proposed testimony. Generally, no identifications or disclosures are required for experts a party does not intend to call at trial, subject to the discussion above regarding experts becoming eyewitnesses. See State ex rel. Richardson v. Randall, 660 S.W.2d 699, 701 (Mo. 1983).

Note that experts’ written reports are generally protected from discovery as work product under Rule 56.01(b)(3) of the Missouri Rules of Civil Procedure. See Carthen v. Jewish Hosp. of St. Louis, 694 S.W.2d 787, 791 (Mo. Ct. App. 1985). However, such reports may become discoverable upon a showing of substantial need and undue hardship. See id. 

Rules Regarding Lawyer-Expert Communications, Draft Expert Witness Reports, Expert Witness Notes, Etc. in Missouri

As stated above, experts’ written reports are generally protected from discovery as work product under Rule 56.01(b)(3) of the Missouri Rules of Civil Procedure. However, the Missouri Supreme Court has held that, at deposition, experts expected to be called at trial must produce all documents and materials the expert has reviewed. State ex rel. Tracy v. Dandurand, 30 S.W.3d 831, 835 (Mo. 2000). This includes those materials that would otherwise be protected as work product or under the attorney-client privilege and those that are not ultimately used in the formulation of the expert’s opinion. Id. at 835-36. Responding to the contention that this rule weakens work product and attorney-client privilege, the Missouri Supreme Court stated: “The expert witness is wholly in the control of the party who retained him or her. If the party’s attorney, in preparing the expert for deposition, finds that privileged documents have been mistakenly provided to the expert, the attorney presumably has the option of withdrawing the expert’s designation prior to deposition.” Id.