Wisconsin Rules Regarding Expert Witness Depositions and Interrogatories

Under section 804.01(2)(d)(1) of the Wisconsin Code, experts that a party expects to call a trial may be subject to deposition. The Wisconsin Code does not impose a specific time limit on such depositions, but section 804.05(2)(b) provides that the court may increase or decrease the time allowed for deposition upon a showing of cause. Experts generally may not be subject to interrogatories in Wisconsin, 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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Wisconsin Expert Witness Reports and Disclosures Rules 

The extent of disclosures required for experts depends on whether the expert is expected to be called at trial or was retained purely for consulting purposes. Information regarding the latter group of experts is not discoverable absent a showing of exceptional circumstances under which it is impracticable for the party seeking discovery to obtain facts or opinions on the same subject by other means.

On the other hand, a party may, through interrogatories, require its opponent to disclose the identities of experts expected to testify at trial. Once identified, the opponent may then depose the expert as discussed above. The Wisconsin Code does not expressly require parties to provide reports from their testifying experts to their opponents. However, section 804.01(2)(d)(1) provides that the court can order further discovery upon motion, and it is common practice for parties to exchange the reports of testifying experts, either by mutual agreement or by court order. See, e.g., Bickford Farms, Inc. v. Wis. Power & Light Co., 820 N.W.2d 156, 156-57 (Wis. Ct. App. 2012) (“The circuit court required the [plaintiff] to disclose their expert witnesses and provide expert witness reports by July 1, 2010.”). 

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

Wisconsin has codified the work product doctrine, protecting against the disclosure of attorney mental impressions and theories prepared in anticipation of litigation, in section 804.01(2)(c)(1). However, the Committee Notes to this provision suggest that communication of this work product to an expert expected to testify at trial may destroy the protection from discovery. Specifically, the Committee cites an article that states:

Attorneys litigating matters in Wisconsin state courts must be mindful of the potential discoverability of the substance of all communications with and all work product reviewed by testifying experts. Even a testifying expert’s notes of oral discussions with counsel and materials containing counsel’s mental impressions and conclusions may be discoverable, regardless of whether the expert relied on such materials in forming opinions.

Michael Matthews, Discoverability of Work-Product Materials Reviewed by Testifying Experts, 75 Wis. Law. no. 6 (2002).

The article then concludes by recommending that, “[t]o the extent attorneys want to discuss theories or topics with an expert without risking disclosure to opposing parties, it would be prudent to retain a nontestifying expert for such purposes.” Id.