The plaintiff ordinarily has the burden of proving that the defendant did not exercise reasonable care and was therefore negligent. The doctrine of res ipsa loquitur (the occurrence or thing speaks for itself) permits an inference of negligence when:
- the event is of a kind which ordinarily does not occur in the absence of someone’s negligence;
- it is caused by something within the exclusive control of the defendant;
- it is not due to any voluntary action or contribution on the part of the plaintiff; and
- the defendant has superior knowledge as to the cause of the event.
Examples of this doctrine would be its application in the case of objects such as bricks or window panes falling from the defendant’s premises, falling elevators, the collapse of structures, and the escape of gas or water from the gas or water main.
Collette worked in a building owned by Acme Company. As part of her job, she was going from one floor to another when the elevator stopped moving. She was alone in the elevator for about an hour before she was rescued. The emergency phone in the elevator was dead. She sued the Acme Company for the mental distress to which she was subjected. Acme Company claimed that it was not liable because there was no proof that it had been negligent. Collette claimed Acme had the burden of proving that it was not negligent. Was she correct? Yes. The concept of res ipsa loquitur justified the conclusion that Acme was negligent, and Acme had the burden of disproving that inference. Res ipsa loquitur has frequently been applied in elevator cases because it applies when (a) the occurrence resulting in injury is such as does not ordinarily happen if those in charge use due care; (b) the instrumentalities involved are under the management and control of the defendant; and (c) the defendant possesses superior knowledge or means of information as to the cause of the occurrence.