What must be proven if a plaintiff wishes to invoke res ipsa loquitur in a products liability case?

In a products liability case, if a plaintiff seeks to invoke res ipsa loquitur, it must be demonstrated that the defect in question could not have occurred without negligence. Res ipsa loquitur, which translates to "the thing speaks for itself," allows a plaintiff to establish negligence based on the nature of the accident alone, without direct evidence of the defendant's actions.

For this doctrine to be applicable, the plaintiff typically needs to show that the product was under the control of the defendant at the time of the accident and that the type of accident that occurred would not normally happen in the absence of negligence. This means the plaintiff does not have to prove what the negligence was or point to specific acts; instead, they rely on the fact that the occurrence itself strongly suggests negligence.

In this context, other options presented do not align with the requirements of res ipsa loquitur. The notion of a product being the best in its category, prior complaints against the product, or the presence or absence of a warranty do not contribute to the establishment of negligence directly related to the occurrence of the defect being argued; hence, they are not relevant factors in invoking res ipsa loquitur.