## Facts

- Twelve-year-old Jerrit Moore was struck and injured by a vehicle driven by Robert Blackwell.
- Terry Moore, as next friend of Jerrit, sued Blackwell for negligence and also named Farmers Insurance Company as a defendant.
- Liability was contested, including whether Jerrit’s conduct contributed to causing the collision.
- At trial, Blackwell presented two opinion witnesses:
  - Michael Thomson, the detective who investigated the collision.
  - Terry Harrison, an accident-reconstruction witness.
- Over the Moore family’s objections, the trial court allowed Thomson to testify that Jerrit was “probably more at fault” than Blackwell.
- Over objection, the trial court also allowed Harrison to testify that Blackwell “was not at fault” for the collision.
- The jury returned a defense verdict, and judgment was entered for Blackwell (and, as styled in the case, the defendants).
- The Moore family appealed, challenging the admission of the fault-allocating opinions.

## Issues

1. Whether the trial court abused its discretion by admitting opinion testimony that directly stated which party was at fault (or not at fault) in a routine negligence case.
2. Whether allowing a police investigator and a reconstruction witness to give such fault conclusions improperly displaced the jury’s role and required a new trial.

## Decision

- The Oklahoma Court of Civil Appeals reversed the judgment and remanded for a new trial.
- The court held it was error to admit Thomson’s opinion that Jerrit was “probably more at fault” than Blackwell.
- The court held it was error to admit Harrison’s opinion that Blackwell “was not at fault.”
- Because these opinions went to the central liability question and carried a high risk of swaying the jury, the error was prejudicial.

## Legal Principles

- Opinion testimony must help the trier of fact understand the evidence or decide a fact in dispute; otherwise it should be excluded.
- In an ordinary negligence trial with facts that lay jurors can evaluate without specialized help, witnesses generally may not state direct conclusions that one party was “at fault,” “more at fault,” or “not at fault.”
- A witness may explain technical matters (such as measurements, timing, visibility, speeds, distances, and physical evidence) but may not tell the jury the legal result to reach on negligence and comparative fault.
- Courts review admissibility of such opinion testimony for abuse of discretion, and reversal is warranted when the improper testimony bears on the main contested issue and likely affected the verdict (consistent with Oklahoma authority such as *Gabus v. Harvey*).

## Conclusion

*Moore v. Blackwell* ordered a new trial because the trial court let defense witnesses go beyond technical observations and offer bottom-line fault conclusions—telling jurors that the child pedestrian was “more at fault” and that the driver was “not at fault”—which improperly substituted witness conclusions for the jury’s decision on negligence and comparative fault.


Moore v. Blackwell, 325 P.3d 4 (2014)