What is res ipsa loquitur, and when is it used in tort cases?

• A. A rule about contract interpretation in negligence cases.
• B. A rule allowing an inference of negligence from the mere occurrence of an event that would not normally occur without negligence; used when direct evidence of defendant’s conduct is unavailable.
• C. A rule requiring direct evidence of negligence; used when there is eyewitness testimony.
• D. A rule limiting damages in products liability.

Answer: (B)

Res ipsa loquitur is a tort principle that allows a fact-finder to infer negligence from the mere occurrence of an event that ordinarily would not happen in the absence of negligence, when the thing causing the injury was under the defendant’s exclusive control and the plaintiff did not contribute to the accident. It steps in precisely where there isn’t direct evidence of what the defendant did wrong, shifting the burden to the defendant to show there was a non-negligent explanation. For example, a surgical instrument left inside a patient or a misplaced appliance falling from a ceiling are classic situations where res ipsa loquitur applies, because such mishaps typically point to negligence and the instrumentality was under the defendant’s control.

The other descriptions don’t fit this doctrine. One describes contract interpretation in negligence cases, which is not what res ipsa loquitur addresses. Another says the rule requires direct evidence or eyewitness testimony, which is the opposite of res ipsa loquitur—this doctrine is invoked precisely when direct evidence of the defendant’s fault is unavailable. The last describes limiting damages in products liability, which is a different area altogether and not about invoking an inference of negligence.