Wisconsin Defense Counsel Advocates for Clarity in Expert Testimony Standards 

By: Nicole Marklein, Cross Jenks Mercer & Maffei LLP

WDC has remained active in legislative efforts to promote a fair civil justice system. Most recently, WDC members testified before both houses of the Wisconsin State Legislature in support of legislation to update Wisconsin Statute § 907.02(1), Wisconsin’s expert testimony statute, to bring it in line with federal law. The legislation, introduced as Senate Bill 459 (SB 459) and Assembly Bill 458 (AB 458), is aimed at bringing Wisconsin’s rules governing expert testimony in line with the amendment to Federal Rule of Civil Procedure 702 (FRE 702) that went into effect on December 1, 2023. 

On October 22, 2025, WDC members Caleb Gerbitz of Meissner Tierney Fisher & Nichols, S.C. and John Pinzl of von Briesen & Roper, S.C. testified before the Senate Committee on Judiciary and Public Safety in favor of Senate Bill 459. On November 5, 2025, the Assembly Committee on Judiciary heard testimony on the corollary Assembly Bill 458. Attorney Nicole Marklein of Cross Jenks Mercer & Maffei LLP testified on behalf of WDC in support of the measure. In their testimony, Attorneys Gerbitz, Pinzl and Marklein emphasized the legislation’s role in promoting fairness and consistency in Wisconsin courts.

On November 18, 2025, the Wisconsin Senate unanimously approved Senate Bill 459 and immediately messaged it to the Wisconsin Assembly for action.

I.              What SB 459/AB 458 Does

For more than fifteen years, Wisconsin Statute § 907.02(1) has required judges to act as gatekeepers, ensuring expert testimony admitted in court is reliable and grounded in sound methodology. In accordance with federal law, SB 459/AB 458 builds on that foundation by clarifying two key points: 

1. Burden of Proof – The party seeking to admit expert testimony must demonstrate its reliability before it reaches a jury.

2. Opinion-by-Opinion Review – Each expert opinion must individually meet reliability standards, rather than relying on a blanket qualification.

These changes reflect current law in Wisconsin courts. By codifying them, SB 459/AB 458 aims to ensure consistent application, eliminate ambiguity and streamline judicial decision-making. 

The proposed amendment reads as follows: 

SECTION 1. 907.02 (1) of the statutes is amended to read: 

907.02 (1) If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise, if the proponent demonstrates to the court that it is more likely than not that the testimony is based upon sufficient facts or data, the testimony is the product of reliable principles and methods, and the witness has applied witness’s opinion reflects a reliable application of the principles and methods reliably to the facts of the case.

SECTION 2. Initial applicability. 

(1) This act first applies to actions or special proceedings that are commenced on the effective date of this subsection.

II.            Why It Matters 

• Alignment with Federal Law: Wisconsin’s current statute was modeled after Federal Rule of Evidence 702, which was amended in 2023 to include similar clarifications. SB 459/AB 458 ensures state and federal standards remain consistent.

• Guidance for Judges and Litigants: Clear rules reduce disputes over admissibility and help attorneys prepare cases with confidence.

• Efficiency and Fairness: When expectations are clear, litigation moves more smoothly, saving time and resources for courts and parties alike.

III.          WDC’s Role in Advancing the Bill

WDC has been proactive in monitoring and supporting legislation that impacts civil litigation in Wisconsin. Working closely with Hamilton Consulting Group, WDC identified the adoption of amended FRE 702 as a priority early in the legislative process. Hamilton provided strategic guidance and coordinated outreach to ensure lawmakers understood the practical benefits of the bill.

IV.          Key Advocacy Actions by WDC

• Early Engagement: Flagged adoption of amended FRE 702 as a priority and worked with Hamilton Consulting to develop a legislative strategy.

• Member Outreach: Solicited feedback and examples from WDC members to illustrate the need for clarity in expert testimony standards. 

• Testimony Coordination: Prepared and delivered testimony through experienced members.

• Legislative Education: Shared written materials and talking points with lawmakers to explain the bill’s benefits for courts and litigants.

• Ongoing Monitoring: Continues to track the bill’s progress and update members on developments.

V.            Looking Ahead 

To date, SB 459/AB 458 has enjoyed widespread bipartisan support. If adopted, this legislation will reinforce Wisconsin’s commitment to reliable expert evidence and fair trials. The bill represents a modest but meaningful step toward greater clarity in civil litigation—a win for judges, attorneys, and the public. 

Author Biography: 

Nicole Marklein is an experienced trial attorney and employment law practitioner based out of Baraboo, Wisconsin. She is a longtime member of WDC, having served as its President and now serving as WDC representative to the Wisconsin Civil Justice Council (WCJC) and as the Wisconsin State Representative to DRI.