Experts Not Allowed to Testify to the Percentage of Fault

Division One recently handed down Webb v. Omni Block, Inc., a clearly written opinion which decisively eliminates an expert’s ability to testify as to the “percentage of fault” for any party or non-party.

In Webb, defendant, Omni Block, hired an expert who testified as to the specific percentage of fault (or lack thereof) for various parties and non-parties. Judge Jones allowed this testimony and the jury came back with an allocation that was very close to the allocation suggested by the defense expert. The Court of Appeals quickly dispatched the portion of the appeal challenging the expert’s qualification and focused, instead, on the appropriateness of the testimony on the “ultimate issue” pursuant to Rule 704.

Rule 704 states that “[t]estimony in the form of an opinion or inference otherwise admissible is not objectionable because it embraces an ultimate issue to be decided by the trier of fact.” The Court noted that a first-blush reading of Rule 704 “appears to support Omni’s argument because it permits opinion testimony [about the percentages of fault] that encompasses an ultimate issue.”

However, the Court observed, pursuant to “the comment to Rule 704, opinion testimony on an ultimate issue must still be helpful to the trier of fact and cannot be couched in legal conclusions that simply opine ‘how juries should decide cases.'” Quoting McCormick on Evidence, the Court noted:


Undoubtedly some highly opinionated statements by the witness amount to nothing more than an expression of his general belief as to how the case should be decided or the amount of damages which would be just. All courts exclude such extreme, conclusory expressions. There is no necessity for this kind of evidence; its receipt would suggest that the judge and jury may shift responsibility for the decision to the witness. In any event, the opinion is worthless to the trier of fact.


“We therefore hold that [Omni’s expert’s] opinion apportioning of percentages of fault to the parties and non-parties constituted inadmissible legal conclusions under Rule 704 because he thereby told the jury how to decide the case. Once [Omni’s expert] testified to the duties and responsibilities of the parties involved, the distribution of fault among the parties responsible was the jury’s responsibility.”

It’s good to see the Court of Appeals finally adding teeth to the Comment to Rule 704. Many of us have used that Comment extensively to advocate for limitations to the substance for expert testimony, and so now that it was the basis of a published opinion, perhaps we will have greater success in getting judges to address the aggressive invasion of the jury’s province by defense experts.