Is an expert's testimony about the psychological connection between the visible presence of unsecured firearms and death by suicide relevant to a jury's determination on negligence?

QUESTION PRESENTED The Federal Rules of Evidence establish the framework within courts must make their determinations as to admissibility. Under Rule 402, the baseline for admissibility is relevance. Evidence is relevant if it tends to increase or decrease the probability of a fact at issue in the action. Fed. R. Evid. 401. The subject of this appeal is whether the district court abused its discretion in excluding testimony and data about the risk of harm that is created when a loaded and unlocked firearm is left in plain view and freely accessible to unauthorized users. THE QUESTION PRESENTED IS: Is an expert’s testimony about the psychological connection between the visible presence of unsecured firearms and death by suicide relevant to a jury’s determination on negligence? ii LIST OF PROCEEDINGS U.S. Court of Appeals for the Ninth Circuit No. 22-35340 Estate of William Han Manstrom-Greening, Appellant v. Lane County, et al,, Appellees Date of Final Judgment: September 5, 2023 U.S. District Court for the District of Oregon No. 6-18-CV-00530-MC Estate of William Han Manstrom-Greening, Plaintiff v. Lane County Parole and Probation, et al. Defendants Date of Final Judgment: March 31, 2022 iii PARTIES TO THE PETITION Petitioner and Plaintiff-Appellant below e Estate of William Han Manstrom-Greening, through Carol J. Manstrom, Personal Representative Respondents and below e Lane County (Oregon) e Lane County Parole and Probation e Donovan Dumire e Glenn Greening