Res ipsa loquitur lets a plaintiff prove breach without showing exactly what the defendant did wrong. The name means the thing speaks for itself. Where an accident is of a kind that does not normally happen without negligence, and the instrument that caused it was under the defendant's control, the jury may infer that someone in the defendant's position was careless. It is a rule of circumstantial evidence, not a separate tort.
Elements
- The kind of accident. It does not ordinarily occur in the absence of negligence.
- Control. The instrumentality was in the exclusive control of the defendant, though modern courts often ask more loosely whether the negligence is more likely than not attributable to the defendant.
- Not the plaintiff's doing. The accident was not caused by any voluntary act or contribution of the plaintiff.
- Effect. In most states the doctrine permits an inference of breach, so the case survives a directed verdict. A minority treat it as raising a presumption that shifts the burden.
Leading cases
- Byrne v. Boadle: a barrel of flour rolled out of a warehouse window onto a passer-by, and the court held the accident itself was evidence of negligence.
- Ybarra v. Spangard: an unconscious surgical patient injured in an unrelated part of the body could invoke the doctrine against the whole medical team, relaxing the exclusive control requirement.
- Escola v. Coca Cola Bottling Co. of Fresno: the majority used res ipsa for an exploding bottle, and the concurrence argued that strict liability was the better tool for product cases.
Where students go wrong
The first mistake is reaching for res ipsa when there is direct evidence of what went wrong. If the plaintiff can show the specific careless act, prove it. The doctrine exists for cases where that evidence is out of reach.
The second is treating exclusive control as a literal requirement. Many modern courts, and the Restatement, ask instead whether the negligence is more probably than not the defendant's, which is what lets multi-defendant medical cases proceed.
The third is thinking the doctrine wins the case. It gets the plaintiff past a directed verdict on breach. Causation, damages and any defenses still have to be argued.
FAQ
Does res ipsa loquitur shift the burden of proof?
In most states it does not. It permits an inference the jury may accept or reject. A minority of states treat it as a presumption that requires the defendant to come forward with evidence.
Can it be used against more than one defendant?
Sometimes. Where a group of defendants had joint control and the plaintiff could not possibly know which one erred, courts have allowed it, as with a surgical team.
Does it apply to medical malpractice?
Yes, but narrowly. It fits obvious errors such as an instrument left inside a patient. Ordinary bad outcomes usually need expert testimony instead.
Related terms
Working through this in your own casebook takes longer than reading it here. Syllume starts from your syllabus and turns each assigned case into a brief you can study from.