How Causation is Determined in California Personal Injury Cases
To succeed with your personal injury claim in California, you must prove four specific elements:
1. A duty of care existed between you and the defendant.
2. The defendant breached the duty of care.
3. The breach caused an injury.
4. The injury is monetarily quantifiable.
Causation is critical because it can indicate who is liable for the injury, how the injury was sustained, and provide the necessary link between the breach of duty and the harm sustained.
If you have been injured in Los Angeles, and believe you have a viable claim against another person or entity, it is important to understand causation. Here, we provide a brief overview. It is always best, however, to schedule a consultation with an attorney who can explain these concepts as they apply to your specific case. Contact us if you are ready, and we will put you in contact with a trusted, experienced personal injury attorney in the Los Angeles metro area.
What is Causation?
Causation is an element of personal injury claims that must be proven by a preponderance of the evidence, which means the alleged cause of the accident or injury is more likely to have happened than not. This standard of proof, however, does not mean that mere speculation is enough to satisfy this element of personal injury claims. The facts and evidence must support it. If the case goes to trial, then the trier of fact-–either the judge or jury––determines causation. But also, there’s a test used to determine causation. In California, the test for causation is the substantial factor test.
What is California’s Substantial Factor Test?
The Judicial Council of California Civil (CACI) Jury Instructions (2020 ed.) 430 defines the substantial factor test:
A substantial factor in causing harm is a factor that a reasonable person would consider to have contributed to the harm. It must be more than a remote or trivial factor. It does not have to be the only cause of the harm.
[Conduct is not a substantial factor in causing harm if the same harm would have occurred without that conduct.]
The substantial factor rule is the rule that all personal injury cases in California must apply to determine causation. You may have heard of the cause-in-fact, also known as the but-for test––this test, however, has been absorbed into the substantial factor rule. It simply meant that but for the defendant’s negligence, gross negligence, recklessness, or intentional act, the injury would not have happened. For example, a car accident would not have happened but for the drunk driver swerving into the other lane.
The substantial factor test considers if the act or omission contributed to the accident leading to the harm. If the harm would still have happened absent the act or omission, then it is not a substantial factor. This is what is usually meant by trivial or remote. Acts or omissions are trivial or remote if they make no difference in causing the harm. For example, you are sideswiped by a vehicle on the highway and injure your arm. When pulled over, another car strikes your car, but it had braked in enough time that the impact was minimal and caused no further bodily injury. The second collision would not be a substantial factor leading to a broken arm (but the driver would be responsible for any additional property damage to your vehicle).
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What Happens When There is More Than One Cause of a Personal Injury?
In many personal injury scenarios, there can be more than one cause and more than one defendant. There could be a proximate cause where, in a chain of events, there is one specific cause that led to the injury and is considered the legal cause, and only one person or entity is found liable. There could, however, also be concurrent causes of an accident where more than one person or entity worked in concert to cause another party an injury. The substantial factor test is meant to determine the proximate cause as well as concurrent causes.
According to CACI 431,
A person’s negligence may combine with another factor to cause harm. If you find that [name of defendant]’s negligence was a substantial factor in causing [name of plaintiff]’s harm, then [name of defendant] is responsible for the harm. [Name of defendant] cannot avoid responsibility just because some other person, condition, or event was also a substantial factor in causing [name of plaintiff]’s harm.
Also, a plaintiff doesn’t need to prove that one act or omission was the sole cause; it’s enough that the plaintiff proves the conduct was a substantial factor even if in combination with other causes. If there is more than one person or entity at fault for causing a single event that led to the plaintiff’s harm, then each defendant is liable jointly and severally to the injured party.
For example, if a truck driver lost control of the truck and struck your vehicle, injuring you and a passenger, there could be concurrent causes for it. The maintenance team could have failed to check the brakes properly and indeed they needed to be repaired. But for the bad brakes, the driver may have stopped the truck in time or may have at least reduced the damage. The truck driver, however, had not been in compliance with federal regulations by not resting enough. He was drowsy and fighting to keep his eyes open at the time of the accident. If he had been more alert, then the accident may not have occurred. Both of these causes are neither trivial nor remote, so each defendant could be held liable. (Further, via vicarious liability, the employer can also be held responsible.) In a successful claim, all defendants would be jointly and severally liable––this maximizes your chances to obtain just and fair compensation. These types of accidents are highly technical, though, so an experienced, resourceful personal injury attorney would be necessary.
Are There Defenses to Causation in California Personal Injury Claims?
Defendants will defend against claims that they caused an accident that led to a plaintiff’s injury. The most likely and most viable defense is that there was a superseding cause. This means that there was a new, separate cause that broke the chain of events leading to the plaintiff’s injury. To avoid legal responsibility, the defendant must prove:
1. A third party’s act or omission occurred after the defendant’s act or omission.
2. The third party’s conduct is highly unusual or extraordinary according to a reasonable person’s perspective.
3. The defendant did not know and had no reason to know about the third party and that it would act the way it did.
4. The harm sustained by the plaintiff was unforeseeable and not reasonably expected.
So, both the superseding conduct and the harm must be unforeseeable or unexpected.
For example, a nursing home is understaffed and a resident wanders off the premises and is assaulted by kids on a bicycle. An assault committed by kids on a bicycle may not be foreseeable and could be considered a superseding cause. If successful, the nursing home may not be found liable. On the other hand, if the resident wandered off and fell on a sidewalk, leading to an injury, this event would likely be foreseeable and so the nursing home would be liable.
Are There Other Causation Tests in California?
The substantial factor test is the only test in California to determine causation in personal injury cases. Before, there had been two tests: the but-for test and the proximate cause test. As mentioned or implied, these tests have been absorbed into the substantial factor test. The only other test is the superseding causation test, which is typically invoked by the defendant to challenge liability.
There is, however, the eggshell plaintiff doctrine (also known as the eggshell skull rule). This doctrine isn’t about causation but is often confused with it. Basically, the doctrine is invoked when the defendant tries to challenge liability because of the plaintiff’s pre-existing condition. In these cases, the plaintiff may have suffered more damages than what would normally be expected under the circumstances because the plaintiff is more susceptible to injury or disease than the ordinary person is. The doctrine protects these types of plaintiffs and requires the defendant to take the victim as he or she is, meaning the defendant must pay for all damages even if larger than anticipated.
As an example of the eggshell plaintiff rule, imagine you were in a car accident ten years ago and suffered a spinal injury. You were treated and have since been pain-free. Yesterday, a motorist rear-ended you in traffic. The property damage wasn’t bad but you suffered severe pain and require medical care and rehabilitation due to the spinal injury. The defendant must fully compensate you even if another person in the same accident may not have suffered much in the way of bodily injury.
Trusted, Resourceful Personal Injury Attorneys in Los Angeles
If you have suffered an injury in Los Angeles, causation must be determined to win compensation. This is true even if you settle before filing a lawsuit or going to trial. An experienced attorney with insight into how these things work will be critical to your case. Contact us so that we can connect you with a personal injury lawyer in Los Angeles equipped with the knowledge and resources you need.
