A negligence case is usually proven through one of two types of evidence: direct and circumstantial. Evidence derived from the personal knowledge of a witness or from images in a photograph or video constitutes direct evidence. Circumstantial evidence, by comparison, requires a fact-finder to draw an inference based on the evidence that has been produced.
Courts have formulated special rules that govern proof in specific instances. In a slip-and-fall case, where a plaintiff’s injury occurs when the plaintiff slips and falls due to a condition on the defendant’s property, courts require the plaintiff to prove that the condition existed for such a length of time that the defendant should have discovered and remedied the condition. Thus, a plaintiff who sues a supermarket when she slips on spilled liquid laundry soap could not recover from the supermarket without showing that the liquid had been on the floor long enough for the supermarket to have discovered it. Evidence that the soap was smeared across the floor due to the number of customers walking on the liquid may be sufficient proof in this type of case.
A plaintiff in some instances may rely on the doctrine of res ipsa loquitur, which is Latin for “the thing speaks for itself.” This doctrine allows a jury to infer that a defendant acted negligently, even without other proof of misconduct. In order for this doctrine to apply, the plaintiff must prove that the event that occurred usually does not happen in the absence of negligence and that the defendant had exclusive control of the instrument that caused injury. For example, the child who was injured by the bag of grain on a public sidewalk may not have any direct or circumstantial proof that the defendant was negligent in handling the bag. However, a bag of grain typically does not fly onto a public sidewalk in the absence of negligence, and the defendant had exclusive control over the bag at the time of the accident. In this instance, the jury may infer negligence on the part of the defendant by employing res ipsa loquitur.