Res ipsa loquitur allows an inference of breach when the event would not ordinarily occur without negligence.

• A. The hospital policy violated
• B. The injury would not ordinarily occur without negligence
• C. The patient signs a waiver
• D. The physician was off duty

Answer: (B)

Res ipsa loquitur rests on the idea that some injuries are so unusual for a type of event that they imply negligence unless proven otherwise. For it to apply, the injury must be of a kind that ordinarily would not occur in the absence of fault, and the instrumentality or situation that caused the injury must have been under the defendant’s control. When those conditions are met, an inference of breach arises even without direct proof of a specific negligent act, shifting some burden to the defendant to show there was no negligence.

The statement that the injury would not ordinarily occur without negligence exactly reflects that core idea, making it the best choice. The other options don’t fit this doctrine: a hospital policy violation is not by itself the trigger for res ipsa loquitur; a waiver doesn’t address the element of the event’s rarity and control; and whether the physician was off duty does not establish the necessary causal and control conditions for inferring negligence.