See also: Tort, Tort law, Negligence
Res ipsa loquitur, sometimes
abbreviated to
res ipsa, is literally
translated as "
the thing speaks for itself." It is a
doctrine applied in
tort cases (particularly when the true circumstances that gave rise to the injury are exclusively known by the defendant) in which the only way in which the
plaintiff's
injury would have occurred is by the
defendant's
negligence.
Res ipsa applies when (1) plaintiff's injury was
caused by an "
instrumentality or
condition" that was in the defendant's exclusive control, (2) under the circumstances, the plaintiff's injury would not normally have occurred if the defendant had not acted negligently, (3) the plaintiff was not responsible for the
event that caused the injury.
I. Exclusive Control of Defendant
Basically, for
res ipsa to
apply, the defendant must be the only
person who could control the instrumentality that caused the injury at the
relevant time. Some courts apply this requirement
narrowly, requiring that the defendant be in control of the instrumentality at the time of the plaintiff's injury. A less
restrictive rule requires that the defendant be in control of the instrumentality at the time any negligence would have occurred. Under the first, narrower, rule,
res ipsa would not apply to a defendant
surgeon who negligently performed an
operation that led to an injury to the
patient only after the patient was no longer in hospital, as the conditions that led to the patient's injury were no longer under the "exclusive control" of the surgeon. The second rule, which requires only exclusive control
at the time the negligence would have occurred would apply
res ipsa, because the physician had exclusive control over the relevant conditions at the time the operation was negligently performed.
This requirement has been criticised by no less than the author of the
standard work on torts,
Dean Prosser:
[R]es ipsa loquitur was reduced to a formula - a catchword easy to
repeat as a substitute for consideration of the evidence.
Unhappily the proof of facts by facts is not capable of reduction to a formula; it has an inconvenient habit of pending always upon the facts. Text writers have much to answer for in this world. The strict and literal application of Wigmore's formula has led to such absurd results as the Rhode Island case in which, in the defendant's department store; the plaintiff sat down in a chair that collapsed, and a directed verdict for the defendant was affirmed upon the ground that both "user" and "control" of the chair were in the plaintiff "at the time of the injury." (Footnote omitted.)
Prosser,
Res Ipsa Loquitur in California, 37 Calif. L. Rev. 183, 187 (1949).
Backlash to decisions such as the Rhode Island decision cited by Prosser have led to a substantial
dilution of this requirement. Now, the plaintiff in that case would likely be able to
recover under
res ipsa, as the chair was in the control of the defendant at the time that it was negligently placed where
customers would likely sit on it.
II. Implied Negligence
Res ipsa loquitur will only apply if, in the normal course of events, the only way the plaintiff's injury would likely have occurred is by negligence on the part of the defendant. In other words, if the defendant had
exercised normal
caution, the injury would not normally have occurred. This
inference of negligence can be supported by
process of elimination, although causes other than negligence on the part of the defendant need not be completely ruled out -
it is only necessary to show that negligence of some kind on the part of the defendant is the most likely explanation for the injury.
III. Injury not Caused by Plaintiff's Conduct
Usually, if the plaintiff did not act negligently in a way that would have contributed to the injury,
res ipsa will apply.
IV. Effect
Usually,
res ipsa is ultimately a
question of fact. The
court will determine whether to
instruct the jury on the application of
res ipsa loquitur, but it will be up to the
jury (or judge in a
bench trial) to decide whether the
inference created by
res ipsa is sufficient to find for the plaintiff. Sometimes, if the plaintiff provides sufficient evidence to give rise to
res ipsa, courts have required the defendant to provide explanatory evidence that
negates the inference of negligence; however, in most cases, the jury will weigh the inference of
res ipsa loquitur against the defendant's explanation.