Burton

This negligence action, for personal injury and wrongful death, arises from shootings by Gary Sanner during an intrusion at his home. The principal question on appeal is whether the trial court prejudicially abused its discretion by admitting the opinions of plaintiffs’ designated expert, a retired police officer, on the reasonableness of Sanner’s conduct. We answer the question in the affirmative and reverse the judgment. The test of reasonableness is an objective one for the jury when, as here, it is just as competent as the expert to evaluate the evidence and draw conclusions. The expert testimony usurped the jury’s role.

FACTUAL AND PROCEDURAL BACKGROUND

Sanner and Jennifer Sanchez married in 2001. She has a son, Shayne Thompson (Shayne), who lived with Sanner and Sanchez in Sanner’s small *15 house in rural Descanso. Numerous times, Shayne climbed through a back window to get into the house when he did not have his key. Sanchez and Shayne moved out of the house in October 2007, and in April 2008 1 she filed for dissolution of the marriage.

On August 8, a Friday, Sanchez placed several calls to Sanner about retrieving the title to Shayne’s truck, which was at…