Res ipsa loquitur is a negligence doctrine that can allow an inference of negligence from the nature of an accident.
Why res ipsa loquitur matters
Res ipsa loquitur matters because a plaintiff may not always know exactly what the defendant did wrong, especially when the defendant controlled the instrumentality or setting. The doctrine can help a claim proceed when the accident is the kind that ordinarily does not happen without negligence.
The doctrine is limited and varies by jurisdiction.
Where res ipsa loquitur appears
Res ipsa loquitur appears in negligence complaints, motions for summary judgment, jury instructions, and trial arguments. It is often discussed in cases involving unusual accidents, medical events, falling objects, or equipment under another party’s control.
Practical example
A surgical instrument is left inside a patient after an operation. The patient may not know which specific person made the mistake, but the circumstances may support a res ipsa loquitur argument.
How res ipsa loquitur differs from nearby terms
Res ipsa loquitur differs from ordinary negligence proof because it allows negligence to be inferred from circumstances rather than proven through direct evidence of a specific careless act. It does not automatically prove damages or every required element.
Related terms
Quick knowledge check
Why can res ipsa loquitur matter when the plaintiff lacks direct evidence of the exact negligent act?