Negligence is one of the most common legal theories in California civil cases. CACI No. 400 sets out the basic elements a plaintiff must prove to hold a defendant legally responsible for harm caused by negligent conduct.
This instruction applies broadly across personal injury, premises liability, product-related negligence, and other civil claims.
What Is CACI No. 400?
CACI No. 400 is the foundational negligence instruction used by California courts. It explains, in plain language, what a plaintiff must establish for a jury to find negligence and award damages.
Unlike more specialized jury instructions, CACI 400 provides the core framework that underlies all negligence claims.
Full Text of CACI No. 400
CACI No. 400. Negligence – Essential Factual Elements
[Name of plaintiff] claims that [he/she/nonbinary pronoun] was harmed by [name of defendant]’s negligence. To establish this claim, [name of plaintiff] must prove all of the following:
- That [name of defendant] was negligent;
- That [name of plaintiff] was harmed; and
- That [name of defendant]’s negligence was a substantial factor in causing [name of plaintiff]’s harm.
New September 2003; Revised February 2005, June 2005, December 2007, December 2011
How Juries Apply CACI No. 400
When applying this instruction, jurors focus on three core questions:
- Negligence
Did the defendant fail to use reasonable care under the circumstances? - Harm
Did the plaintiff suffer actual injury or damages? - Substantial Factor Causation
Was the defendant’s negligence a substantial factor in bringing about the harm?
All three elements must be proven for liability to attach.
Illustrative Example
If a property owner fails to repair a known hazard and a visitor is injured as a result, jurors applying CACI 400 would determine whether the owner acted negligently, whether the visitor was harmed, and whether that negligence substantially caused the injury.
Practical Considerations in Negligence Cases
Negligence claims often depend on:
- Evidence showing what a reasonable person would have done
- Witness testimony and incident documentation
- Expert opinions establishing standard of care
- Proof linking the negligent act to the injury
Even simple negligence cases can become complex when causation or fault is disputed.
Legal Foundation for Negligence Claims
California negligence law is grounded in Civil Code section 1714(a), which establishes a general duty to exercise reasonable care to avoid causing harm to others. CACI No. 400 translates that legal standard into a clear, jury-ready format.
Courts rely on this instruction to ensure jurors apply a consistent and legally correct negligence analysis.
Speak With a Negligence Lawyer
If you were injured due to someone else’s negligence, CACI No. 400 explains the legal standard a jury will apply to your case. WIN Injury & Accident Trial Lawyers can evaluate your claim and explain your legal options under California law.
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