Assembly Bill 458
Admissibility of expert witness testimony
Topics: Court: Procedure, Witness
Stopped before the full Assembly voted
The recommended passing it, but the full Assembly never voted on it. The last day for votes this session was Mar 19, 2026. To try again, a lawmaker would have to start a new bill.
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Introduced, passed
Sep 26, 2025
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Committee, passed
Approved
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Assembly vote, stopped here
Stopped here. The full Assembly never voted on it.
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Senate vote, not reached
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Governor, not reached
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Law, not reached
Latest entry in the official record, Mar 23, 2026: “Failed to pass pursuant to ”
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The same bill was also filed in the Senate as SB 459. That version became law.
Terms on this page
Committee
A small group of lawmakers that looks at a bill first. Most bills never leave committee.
Senate Joint Resolution 1
The session's calendar. Any bill not passed by its last voting day dies.
Official term: Failed to pass pursuant to SJR 1. More in the glossary
Legislative Reference Bureau
The Legislature's nonpartisan office that drafts bills and writes the summary at the top of each one.
Official term: LRB analysis. More in the glossary
Author
A lawmaker who formally puts a bill forward. The text itself is drafted by the Legislative Reference Bureau.
Official term: Author, coauthor. More in the glossary
Signed on in support
Lawmakers who back a bill without being one of its authors, often from the other chamber.
Official term: Cosponsor. More in the glossary
Roll call
A vote where each lawmaker's yes or no is recorded by name.
Official term: Roll call vote. More in the glossary
What it would have done
Summary by the , the Legislature's nonpartisan drafting office. It's their wording, not ours.
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.
Who's behind it
12 representatives are its . All 12 are Republicans.
4 more lawmakers .
See all 16 names Hide the names
Authors (12)
- Brent Jacobson · Republican, Assembly
- Cindi Duchow · Republican, Assembly
- Rob Kreibich · Republican, Assembly
- Clint Moses · Republican, Assembly
- Dave Murphy · Republican, Assembly
- Jeff Mursau · Republican, Assembly
- Jerry O'Connor · Republican, Assembly
- Will Penterman · Republican, Assembly
- Jim Piwowarczyk · Republican, Assembly
- Paul Tittl · Republican, Assembly
- Nancy VanderMeer · Republican, Assembly
- Bob Wittke · Republican, Assembly
Signed on in support (4)
- Dan Feyen · Republican, Senate
- Howard Marklein · Republican, Senate
- Van Wanggaard · Republican, Senate
- Eric Wimberger · Republican, Senate
How lawmakers voted
There was one vote on this bill.
Assembly Committee on Judiciary vote to recommend it
Passed, 8 to 0 · Jan 14, 2026
No member-by-member record exists for this vote. Committee votes and some older sessions record totals only.
Official motion: “Report passage recommended by Committee on Judiciary, Ayes 8, Noes 0”. Official record · This vote on its own page
What happened
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Mar 23, 2026
The session ended, and the bill died with it.
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Jan 14, 2026
Sent to the Assembly Committee on Rules.
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Jan 14, 2026
The committee voted to recommend passing it, 8 to 0.
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Nov 5, 2025
The committee held a public hearing.
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Sep 26, 2025
Sent to the Assembly Committee on Judiciary.
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Sep 26, 2025
Introduced in the Assembly.
See the official record, word for word Hide the official record
- Sep 26, 2025 · Assembly
Introduced by Representatives B. Jacobson, Kreibich, Moses, Murphy, Mursau, O'Connor, Penterman, Piwowarczyk, Tittl, VanderMeer, Wittke and Duchow; cosponsored by Senators Wanggaard, Feyen, Marklein and Wimberger
- Sep 26, 2025 · Assembly
Read first time and referred to Committee on Judiciary
- Nov 5, 2025 · Assembly
Public hearing held
- Jan 8, 2026 · Assembly
Executive action taken
- Jan 14, 2026 · Assembly
Report passage recommended by Committee on Judiciary, Ayes 8, Noes 0
- Jan 14, 2026 · Assembly
Referred to committee on Rules
- Jan 20, 2026 · Assembly
Placed on calendar 1-22-2026 by Committee on Rules
- Jan 22, 2026 · Assembly
Laid on the table
- Mar 23, 2026 · Assembly
Failed to pass pursuant to Senate Joint Resolution 1
Terms on this page
Committee
A small group of lawmakers that looks at a bill first. Most bills never leave committee.
Senate Joint Resolution 1
The session's calendar. Any bill not passed by its last voting day dies.
Official term: Failed to pass pursuant to SJR 1. More in the glossary
Legislative Reference Bureau
The Legislature's nonpartisan office that drafts bills and writes the summary at the top of each one.
Official term: LRB analysis. More in the glossary
Author
A lawmaker who formally puts a bill forward. The text itself is drafted by the Legislative Reference Bureau.
Official term: Author, coauthor. More in the glossary
Signed on in support
Lawmakers who back a bill without being one of its authors, often from the other chamber.
Official term: Cosponsor. More in the glossary
Roll call
A vote where each lawmaker's yes or no is recorded by name.
Official term: Roll call vote. More in the glossary
From the Wisconsin Legislature's official record, checked Sep 15, 2026. See the source
Committee
A small group of lawmakers that looks at a bill first. Most bills never leave committee.
Senate Joint Resolution 1
The session's calendar. Any bill not passed by its last voting day dies.
Official term: Failed to pass pursuant to SJR 1
Legislative Reference Bureau
The Legislature's nonpartisan office that drafts bills and writes the summary at the top of each one.
Official term: LRB analysis
Signed on in support
Lawmakers who back a bill without being one of its authors, often from the other chamber.
Official term: Cosponsor
Roll call
A vote where each lawmaker's yes or no is recorded by name.
Official term: Roll call vote