California Jury Instruction CACI 431 Causation: Multiple Causes

New September 2003

This instruction will apply only when negligence is the theory asserted against the defendant. This instruction should be modified if the defendant is sued on a theory of product liability or intentional tort.

•“ ‘Where several persons act in concert and damages result from their joint tort, each person is held for the entire damages unless segregation as to causation can be established. Even though persons are not acting in concert, if the results produced by their acts are indivisible, each person is held liable for the whole.” (Hughey v. Candoli (1958) 159 Cal.App.2d 231, 240 [323 P.2d 779].)

•“In cases where concurrent independent causes contribute to an injury, we apply the ‘substantial factor’ test of the Restatement Second of Torts, section 423, which subsumes traditional ‘but for’ causation.” (State Dept. of State Hospitals v. Superior Court (2015) 61 Cal.4th 339, 352 fn. 12 [188 Cal.Rptr.3d 309, 349 P.3d 1012].)

•“A defendant’s negligent conduct may combine with another factor to cause harm; if a defendant’s negligence was a substantial factor in causing the plaintiff’s harm, then the defendant is responsible for the harm; a defendant cannot avoid responsibility just because some other person, condition, or event was also a substantial factor in causing the plaintiff’s harm; but conduct is not a substantial factor in causing harm if the same harm would have occurred without that conduct.” (Yanez v. Plummer (2013) 221 Cal.App.4th 180, 187 [164 Cal.Rptr.3d 309].)

•“We are also not persuaded CACI No. 431 confused the jury or diluted the standard for causation. The [defendants] conflate the legal concepts of substantial factor for causation and concurrent cause. CACI No. 431 is necessary to explain to the jury a ‘plaintiff need not prove that the defendant’s negligence was the sole cause of plaintiff’s injury in order to recover. Rather it is sufficient that defendant’s negligence is a legal cause of injury, even though it operated in combination with other causes, whether tortious or nontortious.’ ” (Uriell v. Regents of University of California (2015) 234 Cal.App.4th 735, 746−747 [184 Cal.Rptr.3d 79] [CACI No. 431 properly explained concurrent substantial causes to the jury].)

•“For there to be comparative fault there must be more than one contributory or concurrent legal cause of the injury for which recompense is sought.” (Doupnik v. General Motors Corp. (1991) 225 Cal.App.3d 849, 866 [275 Cal.Rptr. 715].)

•“Because we conclude that, in this case, in which causation was the most critical contested issue and in which there was substantial evidence of multiple causes of [decedent]’ s death, the trial court improperly [refused to instruct] the jury with respect to concurrent causation … .” (Logacz v. Limansky (1999) 71 Cal.App.4th 1149, 1152 [84 Cal.Rptr.2d 257].)

•“Clearly, where a defendant’s negligence is a concurring cause of an injury, the law regards it as a legal cause of the injury, regardless of the extent to which it contributes to the injury.” (Espinosa v. Little Company of Mary Hospital (1995) 31 Cal.App.4th 1304, 1317–1318 [37 Cal.Rptr.2d 541], original italics.)