Did the Trial Court Err When it Refused to Give the Substantial Factor Jury Instruction?

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From the Desk of Josh Hayward:

In a negligence case a plaintiff must prove causation through either a “but for” or a “substantial factor” test. The latter is used where there are potentially multiple causes of a plaintiff’s injury. So, when can a plaintiff’s underlying conditions be brought in to prove causation under a “substantial factor” framework and does that underlying condition require a court to give jury instructions about causation using both tests? The Oregon Court of Appeals recently addressed this question.

Claims Pointer:

The Oregon Court of Appeals examined an appeal by Roberta and Kevin Haas (“Plaintiffs”) who claimed that the trial court erred when it refused to give the substantial-factor jury instruction in addition to the but-for instruction. Plaintiffs argued that since they had underlying conditions that made them more susceptible to injury, the substantial-factor instruction was required. After examining the element of causation as it relates to underlying conditions in-depth, and considering causation in the field of worker’s compensation, the Court of Appeals declined to adopt Plaintiffs’ rule and affirmed the trial court’s decision.

 Haas v. The Estate of Mark Steve Carter, 316 Or. App. 75 (2021).

Facts:

The underlying litigation that this appeal arises from related to an automobile collision where Mark Steven Carter (“Defendant”) struck Plaintiffs’ stopped car from the rear at a relatively slow speed. Plaintiffs allegedly experienced pain shortly after the collision and both claimed that injuries sustained in the accident caused them to need surgery. Plaintiff Roberta Haas received a spinal-fusion surgery several months after the accident. Plaintiff Kevin Haas had a disc-replacement surgery a few years after the accident. Plaintiffs then sued Defendant seeking to recover medical expenses and other damages.

Before trial Plaintiffs had asked the court to deliver both of the uniform jury instructions related to causation. In their request for the substantial-factor instruction Plaintiffs relied on Joshi v. Providence Health Systems, 342 Or 152, 149 P3d 1164 (2006) which stated that the but-for causation instruction is what applies in most negligence cases but identified three categories of cases involving multiple causes where the substantial-factor instruction applies. Plaintiffs argue that their case falls under one of those categories: when a “similar, but not identical result would have followed without the defendant’s act.” Id at 161 (quoting W. Page Keeton, Prosser and Keeton on the Law of Torts 267-68 (5^th ed 1984)). The trial court suggested that they were not persuaded by that argument and thought that Plaintiffs’ concern about their underlying conditions was “addressed by the infirm condition instruction that you take your plaintiff the way that they are.” The trial court also stated that the substantial-factor instruction only applies when there are multiple factors that occur at the same time.

 During trial Plaintiffs presented evidence from which a jury could find that the accident involved speed and force sufficient to cause the injuries that Plaintiffs suffered and sought treatment for. They also presented evidence to support their claim that the accident did cause their injuries. Defendants presented evidence to the contrary which suggested that the speed and forces involved were not sufficient to cause Plaintiffs’ injuries.

In the end, the court gave only the but-for instruction, and the jury returned a defense verdict. On appeal, Plaintiffs argued that the court erred when it didn’t deliver the substantial-factor jury instruction also. The focus of the appeal was the underlying conditions that made both Plaintiffs more vulnerable to suffering the types of injuries that they were treated for after the accident. Plaintiff Roberta Hass had multiple previous spinal surgeries which included the removal of vertebrae and implantation of medical hardware. The surgeon who performed the surgery stated that the condition of her spine pre-accident was “a mess” and that he would not have been surprised if she had the same symptoms that prompted him to perform surgery even without the accident. The surgeon even agreed that a sneeze could have made her symptomatic. Plaintiff Kevin Haas had previous injuries to his neck from other car accidents and had degenerative symptoms which were not uncommon for his age.

Law:  

In a case for negligence there are two uniform instructions about causation: “but-for” and “substantial-factor”. The but-for instruction states that the defendant’s action is the cause of the injury if that injury would not have occurred but for that action. The substantial-factor instruction states that the defendant’s action caused the injury, even when there are other causes, if the defendant’s act was a substantial factor in causing the injury.

The basic principles of negligence require the plaintiff to prove both foreseeability and causation: “[A] plaintiff must establish that the defendant’s conduct created a foreseeable and unreasonable risk” of harm to the plaintiff and that “the conduct in fact caused that kind of harm to the plaintiff.” Sloan v. Providence Health System-Oregon, 364 Or 635, 643, 437 P3d 1097 (2019). Usually, ‘causation’ refers to but-for causation, meaning that the plaintiff must prove that but for the defendant’s negligence, they would not have suffered harm. However, in cases involving multiple causes of the plaintiff’s injury the but-for framework becomes inadequate and instead it becomes more useful to ask whether the defendant’s action contributed to the injury in an important or material way—i.e., whether that negligence was a substantial factor.

Analysis:

The primary question before the Court of Appeals was whether the Plaintiffs provided evidence that supported the giving of the substantial-factor instruction. Before addressing this question, the Court of Appeals addressed and rejected the contention that the substantial-factor instruction only applied in cases where there are multiple tortfeasors that caused the plaintiff’s injury. Rather, they concluded, any cause of the plaintiff’s injury should be considered in the causal analysis.

The Court then addressed the Plaintiffs’ argument that categorically the substantial-factor instruction should be given in every case where a preexisting condition is aggravated or makes a plaintiff more susceptible to injury. The Court rejected this argument and looked towards workers compensation cases to differentiate between underlying conditions that make a person more susceptible to injury and conditions that actively cause an injury. The Court concluded that, in a negligence case, a plaintiff’s underlying condition can be a cause of their injury but only if it actively contributes to causing the injury. Thus, there must be some “causal mechanism” that links the underlying condition to the harm suffered. In this case, the Court held, the Plaintiffs showed no specific evidence that there was a causal link between their underlying conditions and the injuries for which they sought treatment, rather they only claimed that Defendant’s negligent driving was a cause of their injuries. Evidence that the Plaintiffs had underlying conditions that made them more susceptible to injury was not enough by itself, therefore Plaintiffs did not establish that the court was required to give the substantial-factor instruction.  

The Big Picture:

This case highlights the duty that a plaintiff has when proving causation. Just because a plaintiff has underlying conditions that makes them susceptible to injury this does not automatically prove causation. The plaintiff must prove with specific evidence that their underlying conditions were a potential cause of their injuries, not just that they had underlying conditions that made them susceptible to injury. This is important to remember when a court is deciding what jury instructions to provide, as the substantial-factor test may produce different results than the but-for test.