Bill > HB2255

This bill modifies the legal standards for admitting expert witness testimony in Missouri courts, creating different rules for specific types of cases. For certain proceedings like family court, juvenile court, and probate court, experts can testify if their specialized knowledge will help understand evidence, and their testimony can cover ultimate issues. The bill allows experts to base opinions on data reasonably relied upon in their field and to provide opinions without using hypothetical questions. For other types of legal actions, the bill introduces a more stringent standard where the expert testimony must be more likely than not helpful, based on sufficient facts, derived from reliable principles and methods, and reliably applied to the case's specific facts. The bill also clarifies that in criminal cases, experts cannot offer opinions about a defendant's mental state or condition that would constitute an element of a crime or defense, as those determinations are reserved for the judge or jury. Importantly, the bill maintains provisions allowing property owners to testify about their land's reasonable market value, and it provides flexibility for experts to state opinions and explain their reasoning, with the potential for cross-examination of underlying data.

Justice

https://house.mo.gov/Bill.aspx?bill=HB2255&year=2026&code=R