Causation is one of the critical elements of a personal injury claim. In fact, most claims are worthless unless you can prove causation. Proving causation might seem like a simple matter, and it often is. It can be a tough nut to crack, however, without the assistance of an experienced California personal injury lawyer.

Causation in a Negligence Case

Negligence is the most common basis for a personal injury claim. When you allege negligence you are claiming that the defendant injured you through careless behavior. Most car accident claims, for example, trace their roots to negligence. To prove negligence liability, you must prove that:

Causation provides the link between the defendant’s misconduct (running a red light) and your injury (a broken leg.)

The Two Forms of Causation

California, like other states, recognizes two forms of legal causation and expects you to prove both of them. These two forms of legal causation are actual cause and proximate cause.

Actual Cause

When you assert that X was the actual cause of Y, you are asserting that if X hadn’t happened, Y wouldn’t have happened either. This is known as the “but for” test – but for X, you would not have occurred.

For example, if the defendant hadn’t failed to erect a Wet Floor sign, the plaintiff wouldn’t have fallen and broken their hip.

Proximate Cause

The question in proximate cause is whether the causal link between cause and effect was close enough to justify imposing liability on the defendant. The idea is that a freak accident should not result in liability even if the defendant was negligent. 

The classic case illustrating proximate cause is Palsgraf v. Long Island RR. In that case, railroad employees pushed a passenger onto a departing train, causing him to drop his briefcase. The briefcase, containing fireworks, exploded and injured a woman standing some distance away. The woman sued the railroad but lost due to failure to establish proximate cause.

Common Examples of Causation

Sometimes, it’s not easy to determine who or what caused an injury. Following are some examples of causation “close calls”:

Thousands more examples are possible, and you can almost always find a previous case involving a scenario similar to the one you are contesting.

Evidence of Causation

The following items are frequently used to prove causation:

The facts of the case will ultimately determine all of the available sources of evidence.


Negotiating parties typically resolve their disputes based on how they think a court would react if their case went to trial. The problem with causation is that different courts can see the same scenario in different ways. When causation is a prominent issue, your lawyer’s negotiating skills are paramount.

Under California’s comparative negligence scheme, a court will decide each party’s percentage of fault for the accident and deduct the equivalent percentage from each party’s damages. The concepts of “fault” and “causation” can be difficult to tease apart. 

In a nutshell, comparative fault focuses on the wrongfulness of the defendant’s conduct, while causation focuses on the link between the defendant’s misconduct and the injury.

You’ll Probably Need a Hermosa Beach Personal Injury Lawyer if Causation Is in Doubt

Suppose a drunken customer breaks their leg after slipping and falling on an unmarked wet floor at a department store. Is the issue comparative fault, causation, or both? You’ll probably need a lawyer to answer this question. 

Fortunately, personal injury lawyers do not charge legal fees by the hour. They work on a contingency fee arrangement, which means you only pay if you win money. That could be a good reason to schedule a free initial consultation at (424) 722-3209 with a Hermosa Beach personal injury lawyer.