Bill > AB458

This bill updates Wisconsin's statute on expert witness testimony to align with recent changes in Federal Rule of Evidence (FRE) 702, focusing on clarifying the court's role in evaluating expert testimony. Specifically, the bill modifies the existing law by requiring the proponent of expert testimony to demonstrate to the court that it is "more likely than not" that the testimony meets three key criteria: (1) the testimony is based on sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness's opinion reflects a reliable application of those principles and methods to the facts of the case. The primary change is shifting the language from stating that a witness "has applied" principles reliably to requiring that the witness's "opinion reflects a reliable application" of those principles. This modification aims to strengthen the court's gatekeeping function in determining the admissibility of expert testimony, ensuring that such testimony is scientifically sound, methodologically rigorous, and appropriately applied to the specific case at hand. The bill will apply to all actions or special proceedings commenced on or after its effective date.

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https://docs.legis.wisconsin.gov/2025/proposals/reg/asm/bill/ab458