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Res ipsa loquitur: Wikis


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Res ipsa loquitur is a common law theory on the use of circumstantial evidence in tort liability on a negligence theory. The term comes from Latin and means "the thing itself speaks," but is more often translated "the thing speaks for itself." The theory allows the plaintiff to use circumstantial evidence to meet the burden of proof in negligence cases for only the first two elements: duty and breach. Proving these two elements means that, in fact, the defendant was negligent. However, the plaintiff must still prove, by a preponderance of the evidence, that the defendant's negligence was the cause-in-fact of the harm and the proximate cause of the harm before he can recover from the defendant. The theory only applies when, as a matter of law, there is enough evidence to allow a trier of fact to come to a conclusion. It was first formulated in the English 1863 case Byrne v. Boadle.[1]



Under the old common law rule, to use res ipsa loquitur in the proving a breach of negligence the plaintiff must show that:

  1. The harm would not ordinarily have occurred without someone's negligence
  2. The "thing" which caused the harm was under the exclusive control of the defendant at the time of the likely negligent act
  3. There must be an absence of a reasonable explanation as to how the harm occurred.
  4. The plaintiff did not contribute to the harm caused.

However, each jurisdiction applies its own standards to determine negligence under the doctrine of res ipsa loquitur. For example, in New York State, courts have generally held that the doctrine of res ipsa loquitur applies if, first, the accident would not occur in the absence of negligence; second, the instrumentality causing injury was within the exclusive control of the defendant; and third, the plaintiff's voluntary or involuntary actions did not contribute to the accident. Often in dispute is the second element of exclusive control. The defendant's exclusivity of control must be such that the likelihood of injury was, more likely than not, the result of the defendant's negligence. The likelihood of other possibilities do not need to be eliminated altogether but they must be so reduced that the greater probability lies with the defendant.

This is usually referred to in the "scalpel left behind" example of obvious negligence in the case of a physician, in which a person goes to a doctor with abdominal pains after having his appendix removed. X-rays show the patient has a metal object the size and shape of a scalpel in his abdomen. It requires no further explanation to show the surgeon who removed the appendix was negligent, as there is no legitimate reason for a doctor to leave a scalpel in a body at the end of an appendectomy.

The "exclusive control" element has largely given way in modern cases to a less rigid formulation, where the plaintiff must prove that other responsible causes, including the conduct of the plaintiff and third parties, are sufficiently eliminated by the evidence. As a consequence, the element that the plaintiff did not contribute to his injury, is subsumed by the new formulation. Also it is notable that contributory negligence is, in modern case law, compared to the injury caused by the other. For example, if the negligence of the other is 95% of the cause of the plaintiff's injury, and the plaintiff is 5% responsible, then the plaintiff's slight fault cannot negate the negligence of the other. This new type of split liability is commonly called comparative negligence. As a fictitious example:

  • John Doe is injured when an elevator he has entered plunges several floors and stops abruptly.
  • Jane's Corporation built, and is responsible for maintaining, the elevator.
  • Doe sues Jane, and during the proceedings, Jane claims that Doe's complaint should be dismissed because he has never proved, or for that matter even offered, a theory as to why the elevator functioned incorrectly. Therefore, argues Jane, there is no evidence that they were at fault.
  • The court holds that Doe does not have to prove anything beyond the fall itself.
    • The elevator evidently malfunctioned (it was not intended to fall nor is that a proper function of a correctly functioning elevator)
    • Jane was responsible for the elevator in every respect
    • So Jane's Corporation is responsible for the fall.
  • The thing speaks for itself: no further explanation is needed to establish the prima facie case.

In some cases a closed group of people may be held in breach of a duty of care under the rule of Res Ipsa Loquitur. (Ybarra v. Springard, 93 Cal.App2d 43 (1949).) Here, a patient undergoing surgery experienced back complications as a result of the surgery, but it could not be determined exactly which member of the surgical team had breached his or her duty, and so it was held that they had all breached, because it was certain that at least one of them was the only person who was in exclusive control of the instrumentality of harm.

Leading case

The principle of res ipsa loquitur was first put forward by Baron Pollock in Byrne v. Boadle[1] an 1863 English case. Byrne was struck by a barrel of flour falling from a second-story window. The court's presumption was that a barrel of flour falling out of a second-story window is itself sufficient evidence of negligence:

We are all of opinion that the rule must be absolute to enter the verdict for the plaintiff. The learned counsel was quite right in saying that there are many accidents from which no presumption of negligence can arise, but I think it would be wrong to lay down as a rule that in no case can a presumption of negligence arise from the fact of an accident. Suppose in this case the barrel had rolled out of the warehouse and fallen on the plaintiff, how could he possibly ascertain from what cause it occurred? It is the duty of persons who keep barrels in a warehouse to take care that they do not roll out, and I think that such a case would, beyond all doubt, afford prima facie evidence of negligence. A barrel could not roll out of a warehouse without some negligence, and to say that a plaintiff who is injured by it must call witnesses from the warehouse to prove negligence seems to me preposterous.
The present case upon the evidence comes to this, a man is passing in front of the premises of a dealer in flour, and there falls down upon him a barrel of flour. I think it apparent that the barrel was in the custody of the defendant who occupied the premises, and who is responsible for the acts of his servants who had the control of it; and in my opinion the fact of its falling is prima facie evidence of negligence, and the plaintiff who was injured by it is not bound to show that it could not fall without negligence, but if there are any facts inconsistent with negligence it is for the defendant to prove them.

Contrast to Prima facie

Res ipsa loquitur is often confused with prima facie ("at first sight"), the common law doctrine that a party must show some minimum amount of evidence before a trial is worthwhile.

The difference between the two is that prima facie is a term meaning there is enough evidence for there to be a case to answer. Res ipsa loquitur means that because the facts are so obvious, a party need explain no more. For example:

"There is a prima facie case that the defendant is liable. They controlled the pump. The pump was left on and flooded the plaintiff's house. The plaintiff was away and had left the house in the control of the defendant. Res ipsa loquitur."

This may be termed an "open and shut case", meaning that the trial is very brief and almost a formality.

Examples by country


In Canada the doctrine of res ipsa loquitur has been largely overturned by the Supreme Court. In case of Fontaine v. British Columbia (Official Administrator) [1998] 1 S.C.R. 424 the Court rejected the use of res ipsa loquitur and instead proposed the rule that once the plaintiff has proven that the harm was under exclusive control of the defendant and that they were not contributorally negligent a tactical burden is placed on the defendant in which the judge has the discretion to infer negligence unless the defendant can produce evidence to the contrary.

Hong Kong

Some lawyers prefer to avoid the expression res ipsa loquitur (For example, Hobhouse LJ in Radcliff v. Plymouth.[2]. But other lawyers (and judges too) still find the expression a convenient one (for example, see Bokhary PJ, a permanent judge of the Hong Kong Court of Final Appeal, in Sanfield Building Contractors Ltd v. Li Kai Cheong [3].

The expression res ipsa loquitur is not a doctrine but a “mode of inferential reasoning” and applies only to accidents of unknown cause[3][4])

Res ipsa loquitur comes into play where an accident of unknown cause is one that would not normally happen without negligence on the part of the defendant in control of the object or activity which injured the plaintiff or damaged his property. In such a situation the court is able to infer negligence on the defendant's part unless he offers an acceptable explanation consistent with his having taken reasonable care.[3]

South Africa

In South Africa (Roman Dutch Law) there is no doctrine of res ipsa loquitur, although the phrase is used regularly to mean the "facts speak for themselves." Res ipsa loquitur does not shift any burden of proof or onus from one party to the other. The phrase is merely a handy phrase used by lawyers.

United States

Most American courts recognize res ipsa loquitur. The Restatement (Second) of Torts, § 328D describes a two step process for establishing res ipsa loquitur. The first step is whether the accident is the kind that would usually be caused by negligence, and the second is whether or not the defendant had exclusive control over the instrumentality that caused the accident. If found, res ipsa loquitur creates an inference of negligence, although in most cases it does not necessarily result in a directed verdict. The Restatement (Third) of Torts, § 17, adopts a similar test, although it eschews the 'exclusive control' element.

The doctrine was not initially welcome in medical malpractice cases. In Gray v. Wright[5], a seven-inch hemostat was left in Mrs. Gray during gall bladder surgery in June, 1947, and despite her chronic complaints about stomach pain over the years, the device was not found until an X-ray in March, 1953, when it was removed. Her $12,000 award was reversed by the Supreme Court of West Virginia because she was outside the statutes of limitation when she filed and could not prove that the doctor concealed knowledge of his error. This "guilty knowledge" requirement would disappear over the years, and the "discovery rule" by which statutes of limitation run from the date of discovery of the wrongdoing rather than the date of the occurrence has become the rule in most states, allowing res ipsa loquitur to take its rightful place.

Forty years later, leaving a medical device in a patient was medical malpractice, provable without expert testimony, in almost every jurisdiction.[6] Virginia has limited the rule. "In Virginia the doctrine, if not entirely abolished, has been limited and restricted to a very material extent." It may be utilized only when the circumstances of the incident, without further proof, are such that, in the ordinary course of events, the incident could not have happened except on the theory of negligence..."[7]

A contention of res ipsa loquitur commonly is made in cases of commercial airplane accidents. It was part of the commentary in a train collision in California in 2008: "If two trains are in the same place at the same time, someone was negligent."

In some states, the doctrine of res ipsa loquitur is also used as a method of proving the intent or mens rea element of the inchoate crime of attempt. Under the Model Penal Code, "the behavior in question is thought to corroborate the defendant's criminal purpose,"[8] for example:

Possession of materials to be employed in the commission of the crime, which are specifically designed for such unlawful use or which serve no lawful purpose of the actor under the circumstances
Model Penal Code[8]

United Kingdom

England and Wales

In English tort law, the effect of res ipsa loquitur is a strong inference in favour of the claimant that negligence has taken place. It does not however fully reverse the burden of proof (Ng Chun Pui v. Li Chuen Tat 1988)[9].

The requirement of control is important in English law. This requirement was not satisfied in Easson v. LNE Ry [1944] 2 KB 421, where a small child fell off a train several miles after it had left the station. It was considered that the door of the train was not sufficiently under control of the railway company after the train started moving and could have been opened by somebody for whom the company was not responsible. This case was distinguished from the earlier Gee v. Metropolitan Ry[10] where the plaintiff fell from the train immediately after it left the station, when the door through which he fell could still be considered to be fully controlled by the railway company.

The requirement that the exact cause of the accident must be unknown is illustrated by the case of Barkway v. South Wales Transport[11]. In this case a bus veered across the road and it was known that the accident was caused by a flat tire. In this case, the plaintiff could not be assisted by res ipsa loquitur and had to go on to prove that the flat tire was caused by the transport company's negligence.


The doctrine exists in the Scots law of delict. The leading case is that of Scott v London & Catherine Dock Co[12]. This case laid down 3 requirements for the doctrine to apply:

  1. There must be reasonable evidence of negligence
  2. The circumstances must be under the direct control of the defender or his servants
  3. The accident must be of such a type that would not occur without negligence.

Recent examples in Scotland are McDyer v Celtic Football Club[13] and McQueen v The Glasgow Garden Festival 1988 Ltd[14].


  1. ^ a b Byrne v. Boadle Court of Exchequer, 2 H. & C. 722, 159 Eng. Rep. 299, 1863,, retrieved 2009-03-16  
  2. ^ Ratcliffe v. Plymouth & Torbay Health Authority, 1998  
  3. ^ a b c Sanfield Building Contractors Ltd v. Li Kai Cheong, 2003  
  4. ^ Schellenberg v. Tunnel Holdings Pty Ltd, 2000  
  5. ^ Gray v. Wright 142 W. Va. 490, 96 S.E. 2d 671, 1957  
  6. ^ See Fieux v. Cardiovascular & Thoracic Clinic, P.C., 159 Or. App. 637, 641, 978 P.2d 429, 433 (1999); Steinkamp v. Caremark, 3 S.W.3d 191, 198-99 (Tex. Civ. App. 1999); Baumgardner v. Yusuf, 144 Cal. App. 4th 1381, 1392, 51 Cal. Rptr. 3d 1381, 1392 (2006); Fox v. Green, 161 N.C. App. 460, 465, 588 S.E. 2d 899, 904 (2003).
  7. ^ Lewis v. Carpenter Co., 252 Va. 296, 477 S.E.2d 492 (1996). See Virginia Legal Doctrines.
  8. ^ a b Frank Schmalleger, Criminal Law Today: An Introduction with Capstone Cases," p. 115, N. 29, citing Model Penal Code, § 5.01 (2).
  9. ^ Ng Chun Pui v. Li Chuen Tat, RTR, 1988  
  10. ^ Gee v. Metropolitan Ry, 1873  
  11. ^ Barkway v. South Wales Transport, 1 All ER, 1950  
  12. ^ =Scott v. London & Catherine Dock Co 3 H&C 596, 1865  
  13. ^ McDyer v. Celtic Football Club, SC, 2000  
  14. ^ McQueen v The Glasgow Garden Festival 1988 Ltd, SLT  

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