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Bills · 2025-2026 Regular Session

SB 459

Became law Official bill text Atom feed

Relating to: admissibility of expert witness testimony.

Court — Procedure Witness

  1. Introduced, completed
  2. Passes Senate, completed
  3. Passes Assembly, completed
  4. Governor signs, completed
  5. Law, completed

Unfamiliar terms? Glossary

What this bill does

Plain-language analysis by the nonpartisan Legislative Reference Bureau

This bill updates the current statutory rule of evidence relating to testimony by experts to conform with recent changes made to Federal Rule of Evidence (FRE) 702 intended to clarify the court’s gatekeeping role with respect to expert testimony. Current law parallels FRE 702 prior to its amendment, allowing the testimony of an expert witness if the witness’s scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact at issue in the case, but limiting the testimony of an expert witness to testimony that is based on sufficient facts or data, that is the product of reliable principles and methods, and that is based on the witness applying those principles and methods reliably to the facts of the case. Similar to the changes made to FRE 702, the bill confirms that the proponent of the testimony is required to demonstrate to the court that it is more likely than not that the witness’s testimony is based upon sufficient facts or data, that it is the product of reliable principles and methods, and, finally, that the witness’s opinion reflects a reliable application of those principles and methods to the facts of the case.

Sponsors

Introduced by: Feyen (R) , Marklein (R) , Wanggaard (R) , Wimberger (R)

12 cosponsors

B. Jacobson (R) , Duchow (R) , Kreibich (R) , Moses (R) , Murphy (R) , Mursau (R) , O'Connor (R) , Penterman (R) , Piwowarczyk (R) , Tittl (R) , VanderMeer (R) , Wittke (R)

Registered lobbying interests · 7

Organizations that registered lobbying activity on this bill with the Wisconsin Ethics Commission. Registration means interest, not a position for or against. Official record

Votes

Senate: Report passage recommended by Committee on Judiciary and Public Safety, Ayes 8, Noes 0

Passed 8–0 Nov 12, 2025 official source full page

No individual roll call was recorded for this vote. Committee votes and some older sessions record totals only.

Full history

  1. Oct 2, 2025 · Senate

    Introduced by Senators Wanggaard, Feyen, Marklein and Wimberger; cosponsored by Representatives B. Jacobson, Kreibich, Moses, Murphy, Mursau, O'Connor, Penterman, Piwowarczyk, Tittl, VanderMeer, Wittke and Duchow

  2. Oct 2, 2025 · Senate

    Read first time and referred to Committee on Judiciary and Public Safety

  3. Oct 22, 2025 · Senate

    Public hearing held

  4. Nov 12, 2025 · Senate

    Executive action taken

  5. Nov 12, 2025 · Senate

    Report passage recommended by Committee on Judiciary and Public Safety, Ayes 8, Noes 0

  6. Nov 12, 2025 · Senate

    Available for scheduling

  7. Nov 14, 2025 · Senate

    Placed on calendar 11-18-2025 pursuant to Senate Rule 18(1)

  8. Nov 18, 2025 · Senate

    Read a third time and passed

  9. Nov 18, 2025 · Senate

    Ordered immediately messaged

  10. Nov 18, 2025 · Senate

    Read a second time

  11. Nov 18, 2025 · Senate

    Ordered to a third reading

  12. Nov 18, 2025 · Senate

    Rules suspended to give bill its third reading

  13. Nov 19, 2025 · Assembly

    Received from Senate

  14. Jan 16, 2026 · Assembly

    Read first time and referred to committee on Rules

  15. Jan 20, 2026 · Assembly

    Placed on calendar 1-22-2026 by Committee on Rules

  16. Jan 22, 2026 · Assembly

    Rules suspended to withdraw from calendar and take up

  17. Jan 22, 2026 · Assembly

    Read a second time

  18. Jan 22, 2026 · Assembly

    Ordered to a third reading

  19. Jan 22, 2026 · Assembly

    Rules suspended

  20. Jan 22, 2026 · Assembly

    Read a third time and concurred in

  21. Jan 22, 2026 · Assembly

    Ordered immediately messaged

  22. Jan 22, 2026 · Senate

    Received from Assembly concurred in

  23. Jan 28, 2026 · Senate

    Report correctly enrolled

  24. Mar 5, 2026 · Senate

    Presented to the Governor on 3-5-2026

  25. Mar 9, 2026 · Senate

    Report approved by the Governor on 3-6-2026. 2025 Wisconsin Act 92

  26. Mar 9, 2026 · Senate

    Published 3-7-2026