In California, the principle of res ipsa loquitur lets you prove someone’s negligence caused your injuries by the mere fact there is no other reasonable explanation. In short, the only logical conclusion based on the available evidence is that the defendant is liable.
Example: A small plane crashes into the ocean on a clear day. The inspection reveals no defective parts, birds in the engine, or other planes in the area. Plus the sole passenger was strapped into his seat, and the pilot was not on the radio at the time of the accident. Under res ipsa loquitur, there is no reasonable explanation other than that the pilot was negligent.1
Res ipsa loquitur is pronounced RACE IP-sa LOCK-wit-tour. Its Latin translation is “the thing (or matter) speaks for itself.”
What are the elements of res ipsa loquitur?
California Civil Jury Instruction “CACI” 417 spells out the elements of res ipsa loquitur. For you to win a personal injury claim based on res ipsa loquitur, you must establish these three elements:
- The accident or injury would not ordinarily have occurred without negligence,
- The thing or incident that caused your injury was under the defendant’s exclusive control, and
- Nothing you did caused the harm.
Then the burden shifts to the defendant to prove that they were not responsible. If the defendant cannot do this, then you win.2
Is it hard to prove?
While res ipsa loquitur is a simple concept, the application can be tricky. Sometimes it is clear that someone was negligent, but you cannot prove who it was.
Example: An otherwise healthy patient undergoes an emergency appendectomy but wakes up with a paralyzed arm. It is obvious that someone on the surgical team was negligent. Though because the patient was unconscious when the harm occurred, the patient cannot say who was responsible.3
The California Supreme Court has held that plaintiffs in this situation can still make use of res ipsa loquitur: Since all members of a surgical team share control for a patient’s well-being, the burden is on them rather than the plaintiff to explain what went wrong. This prevents the situation in which members of a group avoid liability by staying silent.
Remember, res ipsa loquitur simply shifts the burden of proof to the defendant. Innocent defendants can still avoid liability by:
- Identifying the wrongdoer, or
- Showing that they did not have control of anything that could have harmed the patient.
So a nurse in the above example might be able to testify that orderlies dropped the patient while transferring the patient to the operating table. Or the nurse might be able to show that it was the nurse’s responsibility to watch the surgeon and not the patient.
When can I claim res ipsa loquitur?
You can try to claim res ipsa loquitur in any personal injury case. It is especially common in medical malpractice and vehicle accidents as well as:
- Product liability: For example, the California Supreme Court held that a Coca-Cola bottling plant could be liable for injuries after a bottle of soda exploded when someone opened it.4
- Product maintenance: For example, the California Supreme Court held that a cocktail lounge could be liable for a patron’s injuries when the stool he was sitting on broke. (The patron had not been served any alcohol.)5
- Fires or floods: For example, an auto repair garage was presumed liable for property damage from a fire after it stored automobiles with full tanks of gas within 20 feet of an unvented gas heater.6
Additional Reading
For more in-depth information, refer to these scholarly articles:
- Res Ipsa Loquitur: Its Place in Medical Malpractice Litigation – University of San Francisco Law Review.
- The Doctrine of Res IPSA Loquitur in Negligence Actions – Old Solutions for New Problems – Mississippi Law Journal.
- Res Ipsa Loquitur and Indeterminate Product Defects: If They Speak for Themselves, What Are They Saying – South Texas Law Review.
- Res Ipsa Loquitur: Reducing Confusion or Creating Bias? – Kentucky Law Journal.
- Probability Theory Meets Res Ipsa Loquitur – Michigan Law Review.
Legal References
- Newing v. Cheatham (Cal. 1975) 540 P.2d 33.
- Judicial Council of California Civil Jury Instructions (2024 edition) CACI No. 417. Special Doctrines: Res ipsa loquitur.
[Name of plaintiff] may prove that [name of defendant]’s negligence caused [his/her/nonbinary pronoun] harm if [he/she/nonbinary pronoun] proves all of the following:
1. That [name of plaintiff]’s harm ordinarily would not have happened unless someone was negligent;
2. That the harm was caused by something that only [name of defendant] controlled; and
3. That [name of plaintiff]’s voluntary actions did not cause or contribute to the event[s] that harmed [him/her/nonbinary pronoun]. - Ybarra v. Spangard (1944) 25 Cal.2d 486.
- Zentz v. Coca Cola Bottling Co. of Fresno (1952) 39 Cal.2d 436.
- Rose v. Melody Lane of Wilshire (1952) 39 Cal.2d 481.
- Horner v. Barber (1964) 229 Cal. App. 2d 829.
