Haas v. Estate of Mark Steven Carter

Under UCJI 23.02, when multiple causal factors “operate either independently or together to cause injury,” any one of those factors “may be a cause of the injury” so long as it “was a substantial factor in causing the injury.”

Plaintiff sued defendant for negligence related to a car collision. Jury returned a verdict for the defense, and plaintiff appealed that verdict. Plaintiff’s assigned error to the court’s refusal to deliver the substantial-factor jury instruction along with the but-for instruction. Plaintiffs argued that the substantial-factor instruction should be given in all cases where evidence there is evidence plaintiffs were more susceptible to injury due to an underlying condition. Defendants argued that the but-for instruction was adequate because “there is no evidence of multiple causes acting concurrently to bring about an injurious event requiring the substantial-factor instruction.” Under UCJI 23.02, when multiple causal factors “operate either independently or together to cause injury,” any one of those factors “may be a cause of the injury” so long as it “was a substantial factor in causing the injury.” The Court held that the substantial-factor test only applies when there are multiple causes of injury that act independently or together to cause an injury. In this case the Plaintiffs did not identify anything other than the defendant’s negligent driving which caused their injury. Affirmed.