Res ipsa loquitur is a Latin phrase meaning "the thing speaks for itself." It is a method of proving that a tort occurred in certain types of civil trials. In other words, it permits a plaintiff in certain tort cases to simply invoke res ipsa loquitur to prove the negligence element of a tort cause of action.
Typically, when a plaintiff sues a defendant for a tort, the plaintiff must prove several elements of a case. First, the plaintiff must prove that the defendant intentionally or negligently caused the injuries to occur. Second, the plaintiff must prove that he actually suffered damage as a result of the defendant's actions.
When res ipsa loquitur is invoked, the doctrine permits the plaintiff to win his case without explicitly proving negligence. It, essentially, is a doctrine that says that the action that caused the injury was so obviously negligent that the action speaks for itself and no additional proof is required. If this doctrine applies and is accepted by the court, the plaintiff only has to prove that he incurred damages as a result of the defendant's actions in order to win the case.
Res ipsa loquitur is an acceptable form of proof in the United States, Hong Kong and Scotland. It is known by different names in different countries. Canada has essentially overruled the doctrine of res ipsa loquitor. England uses the doctrine to suggest a strong presumption in favor of assuming negligence, but it cannot be conclusive evidence.
This doctrine is appropriate when an injury-causing action meets four separate criteria. If these four criteria apply, it can be invoked to demonstrate that the action was negligent. This means the plaintiff will be able to win her case without explicitly proving negligence.
The four criteria for res ipsa loquitur to apply are that: the accident would not occur unless negligence was involved; in the particular situation it did not occur without negligence involved; the action or event was caused by an instrument that was under the defendant's exclusive control; and the accident or injury was not in any way caused or contributed to by the plaintiff in the case. This means that if the plaintiff was contributorily negligent, or also behaved in some way that led to the accident, the plaintiff cannot invoke res ipsa loquitur. It also means that whatever harmed the plaintiff must have been exclusively managed or controlled by the defendant and no other individual.