Negligence - Res ipsa loquitur

Learning Outcomes

This article examines the doctrine of res ipsa loquitur within negligence law, explaining when courts permit an inference of negligence from the mere occurrence of an accident, the traditional elements and modern Restatement “class of actors” formulation, and how those requirements are applied in classic categories such as medical malpractice, products, premises, and transportation cases. It details how the doctrine functions as circumstantial proof of breach when direct evidence is missing, how to evaluate control of the instrumentality and plaintiff contribution, and how comparative or contributory negligence doctrines affect use of res ipsa. It analyzes the evidentiary and procedural consequences of successfully invoking res ipsa loquitur, including its role in establishing a prima facie case, defeating motions for summary judgment, directed verdict, or judgment as a matter of law, and the majority versus minority approaches to presumptions and burden shifting. It also discusses how to distinguish res ipsa from strict liability, negligence per se, and ordinary circumstantial evidence, enabling you to recognize bar-style fact patterns that quietly test the doctrine, select the answer choice that correctly describes its effect on the burden of proof, and avoid distractors that mischaracterize res ipsa as creating automatic or strict liability.

MBE Syllabus

For the MBE, you are required to understand how breach of duty can be established, including through circumstantial evidence, with a focus on the following syllabus points:

• Define res ipsa loquitur and explain its purpose in proving breach when direct evidence is lacking.
• Identify and apply the traditional elements:
  • The accident is of a type that ordinarily does not occur without negligence.
  • The instrumentality causing the injury was under the defendant's exclusive control.
  • The plaintiff did not voluntarily contribute to the occurrence.
• Recognize modern trends, including relaxation of the “exclusive control” requirement and the Third Restatement’s “class of actors” formulation.
• Analyze the procedural effect of res ipsa loquitur (inference of negligence, avoiding directed verdict/judgment as a matter of law, possible shifting of burdens in some jurisdictions).
• Distinguish res ipsa loquitur from strict liability and negligence per se.
• Apply the doctrine in fact patterns involving products, medical malpractice, premises liability, and multiple potential defendants.
• Evaluate how comparative or contributory negligence affects use of res ipsa loquitur.
• Determine when res ipsa is inappropriate because direct evidence of the defendant’s conduct is available or because the type of accident does not typically indicate negligence.
• Use procedural posture clues (motions for summary judgment, directed verdict, or judgment as a matter of law) to identify when a question is testing res ipsa loquitur.
• Understand how res ipsa fits into a complete negligence analysis, alongside duty, cause in fact, proximate cause, and damages.

Test Your Knowledge

Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, remember to look more closely at that area during your revision.

1. Res ipsa loquitur allows a plaintiff to establish an inference of negligence based on:
   1. Direct eyewitness testimony of the defendant's specific act.
   2. The defendant's violation of a safety statute.
   3. The nature of the accident itself and surrounding circumstances.
   4. The defendant’s engagement in an abnormally dangerous activity.
2. Which element is traditionally required for res ipsa loquitur?
   1. The plaintiff must prove the defendant’s specific negligent act.
   2. The instrumentality causing the injury must have been under the defendant's exclusive control.
   3. The plaintiff must show the defendant had a specific intent to cause harm.
   4. The defendant must have created an unreasonable risk of emotional distress.
3. Successfully invoking res ipsa loquitur in a majority jurisdiction typically means:
   1. The plaintiff automatically wins the case.
   2. The burden of persuasion on negligence permanently shifts to the defendant.
   3. The plaintiff can avoid a directed verdict for the defendant and the case can go to the jury.
   4. The defendant is treated as strictly liable for the plaintiff's injuries.
4. In which situation is res ipsa loquitur LEAST likely to apply?
   1. A sealed can of soup contains a metal bolt that injures the consumer.
   2. A surgical patient wakes to find a sponge left inside her abdomen.
   3. A driver swerves to avoid a deer and hits a tree.
   4. An automatic sliding door at a store suddenly closes on a customer.
5. Under the Third Restatement approach to res ipsa loquitur:
   1. The plaintiff must always prove the defendant had exclusive control of the instrumentality.
   2. The inference arises if the accident is of a type that ordinarily happens as a result of negligence by a class of actors, and the defendant is a member of that class.
   3. The plaintiff is presumed free from any comparative negligence.
   4. The doctrine applies only in medical malpractice cases with unconscious patients.

Introduction

In most negligence actions, the plaintiff has the burden of proving the defendant's specific negligent act that breached a duty of care. Often, this is done with direct evidence—for example, an eyewitness saw the defendant run a red light or a security camera captured the defendant failing to clean up a spill.

Key Term: Direct Evidence
Evidence that, if believed, directly establishes a fact without requiring the fact-finder to draw an inference, such as a witness’s testimony that she saw the defendant run a stop sign.

In some situations, however, direct evidence of the defendant's negligent conduct is unavailable. The plaintiff may be unconscious during the event, the relevant events may occur behind closed doors, or the physical evidence may be gone. Yet the circumstances surrounding the accident strongly suggest that negligence must have occurred. The doctrine of res ipsa loquitur (Latin for “the thing speaks for itself”) addresses this scenario. It allows negligence to be inferred simply from the fact that an accident happened, provided certain conditions are met.

Key Term: Res Ipsa Loquitur
Latin for “the thing speaks for itself”; a doctrine allowing a fact-finder to infer negligence from the nature and circumstances of an accident, even without direct evidence of the defendant's specific negligent act.

Key Term: Circumstantial Evidence
Evidence that indirectly suggests a fact is true. In negligence, it consists of surrounding facts and conditions from which a jury may infer that the defendant was negligent, even if no one saw the defendant’s precise conduct.

Key Term: Evidentiary Doctrine
A rule about how facts may be proved or inferred in court. Res ipsa loquitur is an evidentiary doctrine; it does not create a separate cause of action but affects how breach of duty can be shown.

The doctrine plays an important role where the defendant is in a much better position than the plaintiff to know what actually happened. Rather than allowing a defendant to escape liability simply because the plaintiff cannot identify a specific misstep, the law sometimes allows the jury to conclude that “the thing speaks for itself”—that the very occurrence of the event points strongly toward negligence by someone in the defendant’s position.

From a policy standpoint, res ipsa loquitur addresses information asymmetry:

• The defendant (hospital, manufacturer, building owner) often has exclusive access to records, equipment, and personnel.
• The plaintiff, especially if unconscious or physically removed from the relevant events, cannot realistically reconstruct the details.
• Without some doctrine like res ipsa, many meritorious claims could never get past a motion for summary judgment or directed verdict, simply because the defendant controls the key evidence.

Res ipsa loquitur does not create automatic liability. Instead, it serves as circumstantial evidence of breach, permitting the plaintiff's case to proceed to the jury even without proof of the specific act that constituted the breach. The doctrine is one route to establish breach when direct proof is missing; duty, causation (both cause-in-fact and proximate cause), and damages must still be proved.

Key Term: Inference of Negligence
A permissible conclusion that the defendant breached a duty of care, drawn from the circumstances of the accident rather than from direct proof of a specific negligent act.

Key Term: Burden of Proof
The overall obligation of a party to produce evidence and persuade the fact-finder on a particular issue. In negligence, the plaintiff generally bears the burden of proof on each element, including breach, causation, and damages.

From an exam standpoint, res ipsa questions often appear in the context of a motion for a directed verdict or summary judgment. The facts will emphasize that:

• No one knows exactly what the defendant did.
• The type of accident rarely happens unless someone was careless.
• The defendant (or a class of actors to which the defendant belongs) was in the best position to prevent the harm.

These questions often ask whether the plaintiff has presented a “prima facie case” of negligence or whether the judge should grant the defendant’s motion because “there is no evidence of negligence.” Recognizing that res ipsa allows negligence to be inferred from the accident itself is important to choosing the correct answer.

Key Term: Directed Verdict (Judgment as a Matter of Law)
A procedural device by which the judge removes a case from the jury and enters judgment for a party because, viewing the evidence in the light most favorable to the opponent, no reasonable jury could find for that opponent.

Key Term: Summary Judgment
A pretrial ruling in which the court decides that there is no genuine dispute as to any material fact and that the moving party is entitled to judgment as a matter of law, based on the evidence produced in discovery.

Key Term: Judgment Notwithstanding the Verdict (JNOV)
A post-trial motion (modernly, a renewed motion for judgment as a matter of law) asking the court to enter judgment contrary to the jury’s verdict because no reasonable jury could have reached that verdict on the evidence presented.

In these procedural settings, the key issue is whether the plaintiff has enough evidence of negligence to reach the jury. Res ipsa loquitur is the doctrine that supplies that evidence when the plaintiff cannot present direct proof of a specific negligent act.

Exam Tip: When you see a motion for summary judgment, directed verdict, or JNOV and the fact pattern stresses that “no one knows what went wrong” but the accident seems extremely unusual, think about whether res ipsa loquitur can supply the missing evidence of breach.

Relationship to Ordinary Negligence Proof

Most negligence claims are proved by a mix of direct and circumstantial evidence. Even without invoking res ipsa loquitur, juries routinely infer negligence from facts such as skid marks, weather conditions, and witness testimony about speed or behavior. Res ipsa loquitur is not a different tort; it is a specialized rule about when the fact of the accident itself is strong enough circumstantial evidence to justify an inference of negligence.

Key Term: Prima Facie Case
The minimum quantum of evidence on each element of a claim that, if believed, would allow a reasonable fact-finder to find in favor of the party with the burden of proof and thus avoid an adverse ruling as a matter of law.

Properly applied, res ipsa loquitur allows the plaintiff to establish a prima facie case of breach, even when the plaintiff cannot say exactly what the defendant did wrong. It is particularly suited to cases involving:

• Unconscious or helpless plaintiffs (e.g., surgical patients under anesthesia).
• Complex instrumentalities controlled by the defendant (e.g., elevators, automatic doors, industrial machinery).
• Sealed products or containers where the relevant conduct occurred out of the plaintiff’s view (e.g., foreign objects in canned food, exploding sealed bottles).

Note that even when res ipsa is available, plaintiffs may also introduce any additional circumstantial or direct evidence they can obtain. The doctrine does not prevent the plaintiff from proving a specific negligent act; it simply provides a fallback route to proof of breach when direct evidence is missing.

Some courts say that res ipsa is most appropriate where direct evidence of the defendant’s conduct is truly lacking. If the plaintiff has detailed proof of what the defendant did or did not do, the case is usually analyzed as an ordinary negligence case rather than through res ipsa. Bar examiners like to test this: if the facts already tell you the defendant was texting while driving, or that a store employee knowingly left a spill on the floor, an answer choice invoking res ipsa is usually unnecessary and not the best explanation.

Exam Tip: Ask yourself, “Do I already know what the defendant did wrong?” If the answer is yes, you probably do not need res ipsa loquitur. If the answer is “No one knows, but this kind of accident is bizarre,” then res ipsa is likely in play.

Historical and Policy Background

Historically, courts were hesitant to let juries infer negligence without direct proof, fearing speculative verdicts. Over time, however, experience with certain types of accidents (classic examples include barrels falling from warehouses and foreign objects in sealed food) convinced courts that sometimes “the thing speaks for itself” so loudly that it would be unfair to insist on direct proof of breach.

Policy reasons supporting res ipsa include:

• Fairness: The defendant is often in sole possession of the information needed to explain what happened, while the plaintiff is unconscious, outside the operating room, or far from the manufacturing process.
• Deterrence: Allowing an inference of negligence encourages actors who control dangerous instrumentalities (hospitals, airlines, manufacturers) to maintain adequate systems and records.
• Judicial efficiency: Without res ipsa, many cases would be dismissed at the motion stage, even though common sense suggests negligence is likely.

At the same time, courts limit res ipsa to categories of accidents that genuinely signal negligence; they do not allow every bad outcome to become a basis for liability.

Key Term: Medical Malpractice
A negligence claim alleging that a health-care provider failed to use the level of care and skill that a reasonably competent provider would use in similar circumstances.

Key Term: Products Liability
A body of law allowing injured plaintiffs to recover for harm caused by defective products, under theories such as negligence, strict liability, and breach of warranty.

Key Term: Premises Liability
Negligence liability imposed on possessors of land (such as businesses or homeowners) for injuries caused by unsafe conditions on their property.

Worked Example 1.1

Patient undergoes abdominal surgery performed by Surgeon at Hospital. Weeks later, Patient experiences severe pain. An X-ray reveals a surgical sponge left inside Patient's abdomen. Patient sues Surgeon and Hospital. Direct evidence of who left the sponge is unavailable as several staff members were present. Can Patient likely invoke res ipsa loquitur?

Answer:
Yes, this is a classic res ipsa loquitur scenario.

First, the accident is of a type that ordinarily does not occur without negligence. Surgical sponges are not supposed to be left inside patients; standard protocols require sponge counts and visual inspection before closure. Jurors can rely on common sense, and courts often admit expert testimony confirming that this is a “never event” absent negligence.

Second, the instrumentalities—the sponges and the surgical field—were under the exclusive or effective control of the surgical team and Hospital at the time of the likely negligence (during surgery). Even though several individuals were involved, modern courts treat the group of medical providers as the relevant “class of actors” responsible for preventing this type of harm.

Third, Patient, being unconscious, did not voluntarily contribute to the injury. There is no plausible way Patient’s conduct caused the sponge to be left behind.

Therefore, res ipsa permits the jury to infer negligence by Surgeon and possibly Hospital staff, even though Patient cannot pinpoint the precise negligent act or actor. The doctrine gets Patient past summary judgment or a directed verdict on breach; Patient still must prove duty, causation (that the retained sponge caused the harm), and damages.

Elements of Res Ipsa Loquitur

For the traditional doctrine to apply, the plaintiff must demonstrate three elements:

• The accident is of a kind that ordinarily does not occur in the absence of negligence.
• The instrumentality or agent that caused the injury was under the defendant’s exclusive control.
• The injury was not due to any voluntary action or contribution by the plaintiff.

These elements channel the inference of negligence toward a particular defendant and away from innocent explanations or the plaintiff’s own conduct.

1. Accident of a Type That Ordinarily Does Not Occur Without Negligence

The first element asks whether common experience (or expert testimony, when lay experience is insufficient) indicates that the event is more likely than not the product of negligence.

Common examples include:

• An elevator that suddenly falls or shoots upward.
• Barrels or heavy objects rolling or falling out of a building onto pedestrians.
• Surgical instruments or sponges left inside a patient after surgery.
• Automatic doors that suddenly slam shut on a person entering or exiting a building.
• A sealed bottle or can that explodes or contains a foreign object.
• A human digit or other plainly foreign object found in sealed food.

In such cases, ordinary people (and sometimes experts) can say: “This kind of thing does not normally happen unless someone was careless.”

Several points are important for MBE purposes:

• The focus is on the type of accident, not on its particular details. The question is not whether this specific accident could possibly have occurred without negligence, but whether accidents of this kind generally do not occur without negligence. The standard is probability, not logical certainty.
• The plaintiff need not rule out all possible non-negligent causes. It is enough if the fact-finder can reasonably conclude that negligence is the more probable explanation for this kind of event.
• In technical or specialized contexts (e.g., complex medical procedures, aircraft systems), lay jurors may not have the necessary background to assess whether a particular outcome usually implies negligence. In these situations, expert testimony may be used to establish that “this does not normally happen unless someone was negligent.”

A critical exam point is that a bad result alone is not enough. Many medical procedures involve risks even when reasonable care is used. For example, a known surgical complication that occurs in a small percentage of operations—even when performed properly—does not, by itself, “speak for negligence.” By contrast, leaving a sponge in a patient or amputating the wrong limb is not a recognized non-negligent complication; those outcomes strongly indicate negligence.

Contrast with accidents that may be unusual but are not strongly associated with negligence, such as:

• A driver who swerves to avoid a suddenly appearing animal and hits a tree.
• A brand-new tire that unexpectedly blows out with no evidence of defect or misuse.
• A person slipping on an object that appears to have just fallen to the floor moments before.
• A tree limb falling during a sudden storm when there was no prior sign of decay.

In these scenarios, there may be nothing in common experience pointing strongly toward negligence by the defendant as opposed to a non-negligent cause.

On the MBE, answer choices that stress “accidents sometimes happen even with reasonable care” are often distractors. The correct inquiry is whether, more often than not, this kind of accident suggests negligence, not whether negligence is the only possible explanation.

Exam Tip: Look for language like “this type of accident does not ordinarily occur in the absence of negligence” or “such events rarely happen unless someone is careless.” Those phrases are signals that the fact pattern is inviting a res ipsa analysis.

Establishing the First Element in Technical Cases

In some contexts, jurors cannot rely solely on general experience. For example:

• A particular type of surgical complication.
• A complex machine failure in an industrial plant.
• A mechanical failure in a modern aircraft.

Here, courts often allow expert testimony to explain whether the accident is of a type that typically indicates negligence. The expert is not telling the jury that “this defendant was negligent,” but rather that “events of this sort generally do not occur absent negligence by someone in charge of this kind of equipment or procedure.”

For exam purposes, if the facts mention that the medical profession regards a particular outcome as “never occurring without a departure from accepted practice,” or that engineers agree the failure “would not occur absent improper maintenance,” that is a strong signal that the first res ipsa element is satisfied.

2. Defendant's Exclusive Control

The second element is designed to connect the likely negligence to the particular defendant.

Key Term: Exclusive Control
A traditional requirement for res ipsa loquitur, meaning the instrumentality that caused the injury was under the defendant’s management and control at the time the alleged negligence likely occurred.

Historically, courts demanded that the defendant have exclusive control of the instrumentality at the time the negligence occurred. If others had equal control or if the item had left the defendant's hands long before the accident, this element might fail.

Classic examples:

• A barrel rolls out of a warehouse window onto a passerby. The warehouse operator has control of the barrels and building; the inference points toward the warehouse operator.
• A patient under anesthesia wakes with a burn on her leg. The surgical team and hospital staff had control of the environment and instruments during the surgery; the inference points toward them.
• A sealed bottle explodes in the consumer’s hand. If the bottle has remained sealed and properly handled after leaving the bottling plant, the bottler may be found to have had effective control at the time the negligence (defective bottling) likely occurred, even though the bottle was physically with the retailer or consumer at the moment of the accident.

Important refinements:

• Control is evaluated at the time of the probable negligence, not necessarily at the time of the injury. For sealed products, the relevant negligence (e.g., improper filling or sealing) occurs at the manufacturing stage, when the manufacturer clearly has control.
• Certain defendants are understood to have legal responsibility for instrumentalities even if they hire others to maintain them. For example, a business that invites the public onto its premises has a nondelegable duty to maintain safe entryways and exits. Even if an independent contractor maintains an automatic door, the business is treated as having control for res ipsa purposes because it bears legal responsibility.

Key Term: Nondelegable Duty
A duty that remains with the defendant even if the defendant hires an independent contractor to perform the work; the defendant cannot escape responsibility by delegating the task.

Modern courts, and the Third Restatement, treat this requirement more flexibly. The key question becomes:

• Is the defendant the most likely responsible party, or
• Is the defendant a member of the class of actors whose negligence typically produces this type of accident?

In many medical malpractice and products liability cases, multiple people or entities share control. Courts frequently allow res ipsa as long as the accident is more likely attributable to negligence by someone in that group, and the plaintiff cannot reasonably identify which particular defendant was responsible.

For MBE purposes, pay attention to whether the defendant was:

• The only party realistically able to prevent the accident, or
• A member of a narrow, well-defined group (for example, the surgical team; the manufacturer and bottler of a sealed beverage).

If the instrumentality passed through many hands, was exposed to the public, or was manipulated by several unrelated actors before the injury, the “exclusive control” element may be problematic. For instance, a banana peel on a supermarket floor might have been dropped by any customer moments earlier; that type of case typically turns on notice, not res ipsa.

Exam Tip: When more than one defendant used or handled the instrumentality (such as a manufacturer and a retailer), ask whether the facts suggest when the defect probably arose. A defect that must have occurred inside a sealed can points upstream to the manufacturer, even though the retailer later possessed the product.

3. Plaintiff's Lack of Contribution

The third element requires that the injury not be due to any voluntary action or contribution by the plaintiff that is more likely than not the cause of the accident.

Traditionally:

• If the plaintiff’s conduct created a substantial possibility that the accident was due to the plaintiff’s own negligence (for example, jumping onto a moving train contrary to warnings), res ipsa would not apply because the accident would not “speak for itself” as pointing toward the defendant’s negligence.
• The plaintiff had to show that she did not interfere with or misuse the instrumentality in a way that might reasonably explain the injury.

This does not mean the plaintiff must be completely blameless. Rather, the doctrine traditionally requires that the plaintiff’s behavior not be a likely, more plausible explanation for the accident than the defendant’s negligence.

Modern comparative-fault jurisdictions often soften this requirement:

• Minor or partial negligence by the plaintiff does not bar res ipsa; instead, it goes to comparative fault and damages.
• The focus becomes whether the accident still “speaks” primarily of the defendant’s negligence, even if the plaintiff’s conduct played some role.

Key Term: Comparative Negligence (Comparative Fault)
A system under which the plaintiff’s recovery is reduced in proportion to the plaintiff’s percentage of fault, rather than being barred altogether.

In pure contributory negligence jurisdictions, however, any proven plaintiff negligence may still bar recovery entirely; res ipsa does not override these substantive rules.

Key Term: Contributory Negligence
A traditional defense under which any negligence by the plaintiff that contributes to the injury completely bars recovery, still followed in a small minority of jurisdictions.

On the MBE, you may see a fact pattern where the plaintiff engaged in somewhat careless but ordinary behavior (for example, lightly leaning on plate glass or walking under a clearly designed passageway). In such cases, courts often allow res ipsa and then address any plaintiff fault under comparative negligence rules, rather than using the plaintiff’s conduct to defeat the doctrine entirely.

Worked Example 1.2

A customer is injured when a bottle of soda explodes as she removes it from a supermarket shelf. The supermarket received the bottles directly from the bottler one day prior. The customer sues both the supermarket and the bottler, invoking res ipsa loquitur. The supermarket argues it lacked exclusive control because the bottler manufactured and sealed the bottle. The bottler argues it lacked exclusive control because the bottle was handled by the supermarket. Can res ipsa loquitur apply?

Answer:
Possibly, particularly under modern approaches that relax strict “exclusive control.”

First, the type of accident—an exploding sealed bottle handled in an ordinary way—ordinarily does not occur without negligence somewhere in the manufacturing, bottling, or handling process. In everyday experience, properly manufactured and stored bottles do not spontaneously explode. That satisfies the first element.

Second, the plaintiff likely did not contribute; she merely lifted the bottle from the shelf, which is normal, foreseeable use. There is no indication that she shook or abused the bottle. The third element is therefore satisfied.

The difficult issue is control. At the time of the explosion, the bottle was in the customer’s physical possession, but the likely negligence (overcarbonation, defective glass, improper capping, or mishandling in storage) occurred earlier, when either the bottler or the supermarket controlled the bottle. Many modern courts allow the inference against one or both defendants if the proof suggests the defect must have arisen while the product was within their joint chain of distribution and was not mishandled afterward.

On an MBE question, if the call asks whether the plaintiff can get to the jury against at least one defendant, the safest answer is usually that res ipsa allows an inference of negligence, at least against the actor most likely responsible for the defect (often the manufacturer), and thus defeats a directed verdict or summary judgment motion.

Worked Example 1.3

A pedestrian is walking past a warehouse when a heavy wooden barrel suddenly falls from an upper window and strikes her. No one actually saw how the barrel came to fall. The warehouse owner offers no explanation but argues that barrels sometimes fall even without negligence. The pedestrian sues, invoking res ipsa loquitur. Is the pedestrian likely to get to the jury?

Answer:
Yes. This is the classic res ipsa loquitur fact pattern often used in textbooks and bar materials.

The first element is clearly met: barrels do not ordinarily fall from warehouse windows onto pedestrians in the absence of negligence. The accident strongly suggests mishandling, improper stacking, or failure to secure the barrels. Common experience allows jurors to conclude that this type of accident usually implies negligence.

Second, the defendant warehouse owner (through employees) controlled the barrels and the building at the time of the likely negligent act—placing or securing the barrels near the window. Members of the public had no access to the interior storage area, so the inference that any negligence was on the part of the warehouse is strong.

Third, there is no indication that the pedestrian contributed to the accident; she was simply walking on a public way.

With those elements satisfied, the pedestrian has enough circumstantial evidence to establish a prima facie case of breach through res ipsa. The doctrine allows the case to go to the jury even though there is no direct evidence of what went wrong inside the warehouse. A directed verdict or summary judgment for the warehouse on the ground of “no evidence of negligence” would be improper.

Worked Example 1.4

A tourist climbs over a clearly marked barrier at a scenic overlook to take a photograph. While standing beyond the barrier, the railing he leans on collapses and he falls, suffering injuries. He sues the park authority, invoking res ipsa loquitur, arguing that railings do not ordinarily collapse without negligence. Should the court apply res ipsa?

Answer:
Probably not under the traditional approach, and only with difficulty under modern law.

It may be true that railings ordinarily do not collapse without negligence in design, construction, or maintenance. That supports the first element. The park authority also had effective control over the structure when any negligence (e.g., failing to repair rot) likely occurred, satisfying the second element.

However, the third element is problematic. The tourist’s conduct was a substantial, voluntary departure from how the area was intended to be used: he ignored clear warning signs and deliberately entered a restricted area. The barrier itself signaled that the area beyond was not maintained for public use. The collapse might have been caused by negligent maintenance, but it is at least as plausible that the tourist’s misuse—leaning heavily on an unmaintained, non-public railing—was the principal cause of the injury.

In a traditional or contributory-negligence jurisdiction, courts are likely to hold that the accident does not clearly “speak” of the defendant’s negligence alone and to refuse res ipsa. In a comparative-fault jurisdiction, a court might be more willing to allow an inference of negligence but then substantially reduce the tourist’s recovery for his substantial share of fault. On the MBE, if the question emphasizes the tourist’s deliberate disregard of warnings, an answer denying res ipsa is usually preferred.

Procedural Effect of Res Ipsa Loquitur

Successfully invoking res ipsa loquitur does not automatically mean the plaintiff wins or that the defendant is conclusively presumed negligent. Its primary effect is evidentiary.

In most jurisdictions (and for MBE purposes), the doctrine has these effects:

• Inference of Negligence (permissive inference):
  • The jury may, but is not required to, infer that the defendant was negligent.
  • The inference arises from the fact pattern itself, without direct proof of specific negligent conduct.
• Avoiding Directed Verdict / Summary Judgment:
  • Res ipsa allows the plaintiff’s case to go to the jury even without direct evidence of breach.
  • The judge generally cannot grant a directed verdict (or summary judgment) for the defendant solely because the plaintiff lacks direct evidence, as long as the res ipsa elements are satisfied and no conclusive contrary evidence is presented.

Key Term: Burden of Production
The obligation to come forward with enough evidence on an issue to prevent an adverse ruling as a matter of law; if a party fails to meet this burden, the court may grant a directed verdict or summary judgment against that party.

Key Term: Burden of Persuasion
The obligation to convince the fact-finder of the truth of a claim or defense to the required standard (in civil cases, typically a preponderance of the evidence).

• Burden of Proof:
  • In the majority of jurisdictions, the burden of persuasion on negligence remains with the plaintiff throughout the case.
  • The defendant faces a practical need to produce evidence explaining the accident or showing due care, but the formal burden of proof does not shift.
  • A minority of jurisdictions treat res ipsa as creating a rebuttable presumption, shifting at least the burden of production—and occasionally the burden of persuasion—to the defendant. Unless a question specifies such a minority rule, assume the majority “permissive inference” approach on the MBE.

Key Term: Rebuttable Presumption
A presumption that a fact exists (for example, the defendant’s negligence) that will stand unless the opposing party produces sufficient evidence to rebut it. Once rebuttal evidence is introduced, the presumption may disappear, leaving the issue for the fact-finder.

Also, if direct evidence of how the accident occurred is available, res ipsa is generally unnecessary and often inapplicable. The doctrine is reserved for situations where the circumstances are the primary evidence of negligence. Some courts say that if the plaintiff introduces detailed direct evidence of the defendant’s conduct inconsistent with the res ipsa inference, the case should be decided on that direct evidence rather than by relying on res ipsa.

Res Ipsa and Motions

On the MBE, the procedural posture is a major clue that a question is testing res ipsa loquitur. Common set-ups include:

• A defendant moves for summary judgment, arguing that the plaintiff has “no evidence” of negligence.
• After the plaintiff rests at trial, the defendant moves for a directed verdict (or judgment as a matter of law) on the same basis.
• After a jury verdict for the plaintiff based on an inference from the accident, the defendant moves for judgment notwithstanding the verdict (JNOV).

In each of these, the key issue is whether the circumstantial evidence supports a reasonable inference of negligence. If the elements of res ipsa are met, the court should allow the case to go to the jury and should not take the case away on the ground of insufficient evidence of breach.

If the jurisdiction treats res ipsa as creating a rebuttable presumption that shifts the burden of production:

• Once the plaintiff establishes the elements, the defendant must come forward with some evidence suggesting a non-negligent explanation.
• If the defendant fails to produce such evidence, the jury may be instructed that it must find negligence.
• If the defendant produces adequate rebuttal evidence, the presumption may “burst,” leaving only a permissible inference for the jury to consider alongside all the evidence.

Test questions will usually signal this minority approach by expressly stating that the jurisdiction follows a rule that “creates a presumption of negligence, shifting the burden to the defendant to prove the absence of negligence.” If the question is silent about presumptions, assume the majority permissive-inference approach.

Exam Tip: When you see the phrase “the jury may infer negligence” you are in majority-rule territory. When the facts say “the law presumes negligence unless the defendant proves otherwise,” you are in a minority, presumption-shifting jurisdiction.

Worked Example 1.5

A visitor enters a hospital through automatic sliding doors. As he walks through, the doors suddenly close on him, causing serious injuries. The hospital presents no specific evidence about maintenance of the doors. The visitor sues the hospital. The hospital moves for summary judgment, arguing that the visitor has no direct evidence of negligent maintenance. Should the motion be granted?

Answer:
No. Res ipsa loquitur gives the visitor enough circumstantial evidence on breach to defeat summary judgment.

First, the type of accident—automatic entrance doors suddenly closing on a person using them in the ordinary way—is an event that common experience tells us does not ordinarily occur if those responsible for maintenance use reasonable care. Jurors can conclude that such malfunctions usually indicate negligent inspection or repair.

Second, the hospital, as owner and operator of the premises, has a nondelegable duty to maintain safe entrances. Even if the hospital hired an independent contractor to service the doors, the hospital is treated as having effective control for res ipsa purposes. The accident is of the type that ordinarily happens as a result of negligence by the class of actors responsible for maintaining such doors, and the hospital is a member of that class.

Third, there is no indication that the visitor misused the doors or contributed to the accident. He simply walked through them as intended.

Under the Third Restatement formulation, and under traditional res ipsa analysis, a reasonable jury could infer negligence from these facts. Therefore, the judge must deny the hospital’s motion for summary judgment and allow the case to go to the jury on the issue of breach, even though the visitor lacks direct evidence of what went wrong inside the door mechanism.

Three Approaches to the Procedural Effect

Different jurisdictions define the effect of res ipsa loquitur in slightly different ways. For the MBE, focus on the majority view, but be aware of alternatives:

• Permissive inference (majority):
  • The jury may—but is not required to—infer negligence.
  • No formal burden shifts; the defendant may remain silent and argue that the inference is unwarranted.
  • The judge’s role is to determine whether a reasonable jury could make the inference; if so, the case goes to the jury.
• Rebuttable presumption shifting the burden of production (some jurisdictions):
  • Once res ipsa is established, a presumption of negligence arises.
  • The defendant must produce evidence showing a non-negligent explanation or due care (e.g., maintenance records, expert testimony).
  • If the defendant produces such evidence, the presumption may disappear, leaving the jury to weigh all the evidence, including the circumstantial evidence that gave rise to the presumption.
• Rebuttable presumption shifting the burden of persuasion (rare):
  • The defendant must persuade the fact-finder that it was not negligent.
  • If the defendant fails to carry this burden, the plaintiff prevails on negligence.

Unless an MBE question specifically mentions a presumption or shifting burdens, assume the first model: a permissive inference that allows, but does not compel, a finding of negligence and primarily affects whether the case may go to the jury.

Worked Example 1.6

After a surgical procedure involving several physicians and nurses, a patient wakes with nerve damage in her arm, unrelated to the area of surgery. She sues all medical providers involved. At trial, she offers no direct evidence of what any particular defendant did wrong, but establishes that the injury occurred while she was unconscious in the operating room. Defendants move for a directed verdict, arguing that she has not identified a specific negligent act or actor. How should the court rule in a majority jurisdiction?

Answer:
The motion should be denied; the case should go to the jury under res ipsa loquitur.

The first element is satisfied because nerve damage in an arm, occurring during surgery on another part of the body, is not a typical complication of that procedure if proper care is used. Expert testimony can establish that such injuries do not ordinarily occur absent negligence in positioning, padding, or monitoring the arm.

The second element is addressed by treating the surgical team as a group in effective control of the patient and equipment during the operation. The patient was unconscious and helpless; all instrumentalities that could have caused the injury were under the collective control of the multiple defendants.

Third, the patient clearly did not contribute to the harm while anesthetized.

Many courts in these “Ybarra-type” situations permit res ipsa against all members of the surgical team and sometimes impose a burden of explanation on them. Even under the majority permissive-inference approach, the plaintiff’s evidence is sufficient to allow a reasonable jury to infer that at least one of the defendants was negligent. The inability to pinpoint the exact actor does not justify taking the case from the jury. Thus, a directed verdict for the defendants is improper.

Exam Warning: Distinguishing Res Ipsa Loquitur

Do not confuse res ipsa loquitur with other doctrines:

• Strict Liability:
  • Imposes liability without proof of negligence for certain activities (e.g., abnormally dangerous activities, wild animals, some product defects).
  • The plaintiff does not have to show that the defendant failed to exercise reasonable care; it is enough to show that the defendant engaged in the activity and caused the harm.

Key Term: Strict Liability
Liability imposed without proof of negligence or intent, typically for abnormally dangerous activities, certain product defects, or harm caused by wild animals.

Key Term: Abnormally Dangerous Activity
An activity that creates a foreseeable and highly significant risk of physical harm even when reasonable care is exercised, and that is not common in the community (for example, blasting with explosives), often triggering strict liability.

• Negligence Per Se:
  • Uses violation of a safety statute or regulation to establish breach of a statutory standard of care.
  • Requires proof that:
    • The statute was designed to protect the class of persons including the plaintiff, and
    • The statute was intended to prevent the type of harm that occurred, and
    • The defendant violated the statute in a way that caused the harm.

Key Term: Negligence Per Se
A doctrine under which an unexcused violation of a safety statute or regulation constitutes breach of the standard of care if the statute was intended to protect this plaintiff from this type of harm.

• Direct Evidence of Negligence:
  • When the plaintiff has specific evidence of the defendant’s negligent conduct (e.g., eyewitness testimony that the defendant ran a red light), ordinary negligence analysis applies.
  • Res ipsa is generally unnecessary in such situations and is usually tested where direct evidence is absent.

On the MBE, when answer choices describe res ipsa as creating strict liability or guaranteeing the plaintiff’s success, those choices are almost always incorrect. Similarly, do not select an answer that treats res ipsa as interchangeable with negligence per se. Res ipsa is about inferring negligence from the nature of the accident; negligence per se is about using statutes to define the standard of care.

A useful way to keep the doctrines separate:

• If the fact pattern emphasizes a safety statute and the defendant’s violation of that statute, you are probably dealing with negligence per se.
• If the fact pattern emphasizes the unusual nature of the accident and lack of direct evidence about what happened, you are likely dealing with res ipsa loquitur.
• If the fact pattern emphasizes an abnormally dangerous activity or defective product with no need to prove fault, strict liability may be the best fit.

Also remember that a single fact pattern may support more than one theory of liability. For example, an exploding soda bottle may allow:

• A res ipsa inference against the bottler or seller (negligence theory).
• A strict products liability claim if the jurisdiction recognizes such actions.

On MBE questions, read carefully whether the call of the question asks for the “best” theory or simply whether the plaintiff can recover; both negligence and strict liability might be available, but the strongest doctrine will often be the one that fits the facts most precisely.

Exam Tip: When multiple theories seem possible, ask which one the facts are tailored to highlight. A focus on control and unusual accidents points to res ipsa; a focus on statutes points to negligence per se; a focus on dangerous activities or product defects without mention of fault suggests strict liability.

Modern Trends and Variations

Modern courts and the Restatement (Third) treat the doctrine somewhat more generously than traditional formulations.

Relaxed “Exclusive Control”

• Medical malpractice:
  • In cases where medical personnel negligently harm a patient who was unconscious or otherwise helpless, some jurisdictions allow an inference of negligence against all defendants who had control over the patient or instruments, unless an individual defendant can exonerate themselves.
  • This approach, sometimes described as a “group responsibility” rule (often associated with the well-known Ybarra-type scenario), reflects the reality that the patient cannot know which of several providers caused the injury, while the providers collectively are in the best position to know.
  • A few jurisdictions go further and shift the burden of persuasion to the defendants, holding them jointly and severally liable unless they can affirmatively prove they were not negligent.

Key Term: Joint and Several Liability
A rule under which each of multiple negligent defendants is liable for the entire amount of the plaintiff’s damages; a defendant who pays more than its share may seek contribution from other responsible defendants.

• Products liability:

  • When a defective product injures a consumer, courts may relax the exclusivity requirement when it is clear the defect likely originated upstream (e.g., before the product was sealed or packaged).
  • This is common in cases involving sealed containers or tightly controlled manufacturing processes.
  • Even though the product may have passed through multiple hands (manufacturer, distributor, retailer), the doctrine may still be applied to those actors whose processes most likely created the defect, particularly when the product remained sealed and was handled in a normal way after leaving their control.

• Premises liability:

  • As illustrated by the automatic door example, businesses with nondelegable duties to maintain safe premises may be treated as being “in control” of mechanical systems even if independent contractors handle day-to-day maintenance.
  • This allows injured invitees to invoke res ipsa based on malfunctions of elevators, escalators, and automatic doors when the malfunction is of a type that ordinarily suggests negligent maintenance.

Third Restatement Approach

The Third Restatement reframes res ipsa loquitur in broader terms:

Key Term: Class of Actors
A group of potential tortfeasors who typically have responsibility for a particular type of risk or activity, such that accidents of a certain kind ordinarily result from negligence by someone within that group (e.g., manufacturers of sealed food products, hospitals maintaining automatic doors).

Under this approach:

• The fact-finder may infer that the defendant has been negligent when:
  • The accident causing the plaintiff’s harm is a type of accident that ordinarily happens as a result of negligence of a class of actors; and
  • The defendant is a member of that class.

This formulation:

• De-emphasizes strict exclusive control, and
• Focuses instead on whether the accident typically results from negligence by actors in the defendant’s position (e.g., hospitals, manufacturers, airlines, landlords).

From an MBE standpoint, this explains why res ipsa may apply even when multiple parties have been involved or when the defendant is one of several potential actors, as long as the accident is of a type ordinarily associated with negligence by that class of actors. Fact patterns involving aircraft parts falling from planes, defects in sealed food, or injuries from hospital equipment frequently invite application of this broader standard.

Comparative Negligence and the Plaintiff’s Contribution

As noted earlier, the third traditional element—no contribution by the plaintiff—is applied more flexibly in many modern comparative-fault jurisdictions.

• Minor carelessness by the plaintiff that does not materially explain the accident will ordinarily not defeat res ipsa.
• Even where the plaintiff’s conduct played some role, courts may still allow res ipsa to establish an inference of the defendant’s negligence, then reduce the plaintiff’s recovery based on comparative negligence principles.

This trend reflects a policy choice: it would be harsh to deny a plaintiff any inference of negligence by the defendant merely because the plaintiff was slightly careless, especially when the defendant’s conduct or instrumentalities were the primary cause of the unusual event.

In contributory negligence jurisdictions, by contrast, if the plaintiff’s negligence is found to be a cause of the accident, recovery is barred entirely, regardless of res ipsa. That said, the plaintiff can still use res ipsa to prove the defendant’s negligence in the first place; contributory negligence is a separate defense that the defendant must prove.

Worked Example 1.7

A shopper leans slightly against a supermarket’s large plate-glass window while looking at a display. The glass suddenly shatters, and the shopper is injured. The shopper sues the supermarket, invoking res ipsa loquitur. The supermarket argues that the shopper contributed to the injury by leaning on the glass. Should res ipsa apply?

Answer:
Yes, in most modern jurisdictions, res ipsa would apply and any minor plaintiff fault would be handled through comparative negligence.

First, large plate-glass windows in commercial premises are expected to withstand ordinary, foreseeable contact such as light leaning. They are specifically designed and installed to remain intact in normal use. A window that shatters under minimal pressure suggests negligent design, installation, choice of glass, or maintenance. Thus, the accident is of a type that ordinarily does not occur without negligence.

Second, the supermarket, as the premises owner, had effective control over the window at the time of the likely negligence (selection, installation, inspection). Members of the public had no authority to alter or weaken the glass.

Third, although the shopper leaned on the glass, her conduct was ordinary and foreseeable. It does not provide a strong, independent explanation for the breakage. In comparative-negligence jurisdictions, this conduct might warrant a small allocation of fault but does not defeat the inference that the primary cause was the store’s failure to maintain safe windows.

Therefore, res ipsa allows the jury to infer negligence by the supermarket and send the case to the jury, while comparative fault principles can address any minor contribution by the shopper.

Worked Example 1.8

A driver is traveling within the speed limit on a rural road at night. A deer suddenly darts into the road. The driver swerves to avoid the deer and crashes into a tree, injuring his passenger. The passenger sues the driver and argues that res ipsa loquitur shows the driver must have been negligent because cars do not normally crash into trees without negligence. Should the court apply res ipsa?

Answer:
No, res ipsa loquitur should not apply on these facts.

While many car crashes do involve negligence, ordinary experience also shows that sudden emergencies—like animals darting into the road—can cause accidents even when a driver exercises reasonable care. The relevant “type of accident” here is not “car hits tree” in the abstract, but “car hits tree after swerving to avoid a suddenly appearing animal.” That scenario is not one that “ordinarily does not occur” without negligence.

Furthermore, the fact pattern does not suggest any special instrumentalities under the defendant’s exclusive control that are typically safe when properly maintained (such as elevators or automatic doors). Ordinary vehicle collisions usually require specific proof of negligence (speeding, intoxication, distraction), not a bare inference from the occurrence of the crash.

Therefore, the first element of res ipsa is not satisfied. The passenger may still pursue a standard negligence theory by trying to show specific careless conduct, but cannot rely on res ipsa to infer negligence solely from the fact of the crash. On an MBE question, the best answer would state that res ipsa does not apply because the accident is equally consistent with non-negligent conduct.

Where Res Ipsa Loquitur Does Not Apply

Understanding when the doctrine does not apply is as important as knowing when it does. Common situations where res ipsa is inappropriate include:

• Ordinary auto accidents with known conduct:
  • If the facts describe how the collision occurred (e.g., the defendant ran a red light, was speeding, or was distracted), the case is simply an ordinary negligence claim proved with direct and circumstantial evidence. Res ipsa adds nothing.
  • Even when the precise speeds are unknown, routine car crashes usually are not treated as the kind of accident that “ordinarily does not occur without negligence” in the way that falling barrels or exploding sealed bottles are.
• Accidents equally consistent with non-negligent causes:
  • A driver swerves to avoid a child darting into the street and hits a parked car.
  • A tree branch suddenly falls on a pedestrian during a storm with no prior visible defect.
  • A tire blows out on a well-maintained car after hitting unforeseen road debris.
  • In these situations, the type of accident is not strongly associated with negligence by the defendant; it may simply reflect the risks of life even when reasonable care is used.
• Plaintiff’s own misuse is the more likely explanation:
  • A consumer uses a power tool in a way clearly contrary to warnings and is injured by kickback.
  • A person climbs onto a clearly off-limits structure and it collapses.
  • A trespasser plays on a locked construction crane and is injured when it moves.
  • Here, even if the defendant might also have been careless, the incident does not “speak” primarily of the defendant’s negligence.
• Detailed direct evidence is available:
  • If a surveillance video shows exactly how a store employee left a spill on the floor for 30 minutes, the issue is no longer whether the nature of the accident implies negligence but whether the employee’s specific conduct met the reasonable person standard. Courts generally analyze such cases without invoking res ipsa.
• Routine medical complications:
  • Many adverse outcomes in medicine—such as infections, blood clots, or certain known surgical complications—occur even when physicians exercise reasonable care. Unless expert testimony shows that the specific complication almost never occurs absent negligence, the bad medical result alone does not support res ipsa. Doctors are not insurers of perfect outcomes.

On the MBE, be alert for answer choices that reflexively invoke res ipsa whenever an accident is unusual. Unless the fact pattern stresses a lack of direct evidence and indicates that this type of accident strongly suggests negligence, res ipsa may be inappropriate.

Worked Example 1.9

A consumer opens a sealed can of soup produced by a national food company and sold by a local supermarket. While eating the soup, she bites down on a small metal bolt and breaks a tooth. The can was sealed until the consumer opened it, and she used an ordinary can opener. She sues the manufacturer for negligence, but has no direct evidence of any specific manufacturing error. Can she rely on res ipsa loquitur?

Answer:
Yes, she can. This is one of the classic factual settings for res ipsa loquitur.

First, sealed cans of food do not ordinarily contain metal bolts if reasonable care is used in manufacturing and quality control. The presence of such an object is strongly indicative of negligent processing or inspection. That satisfies the first element.

Second, the likely negligence occurred while the product was in the manufacturer’s control—when the soup was prepared, filled, and sealed. After sealing, it would be extremely difficult for a retailer or consumer to introduce a bolt into the contents without obvious tampering. Thus, the relevant instrumentality (the can and its contents at the time of the probable negligence) was under the manufacturer’s exclusive control.

Third, the consumer opened and ate the soup in a normal manner. She did not contribute to the presence of the bolt.

On these facts, a jury may infer that the manufacturer was negligent in its production or inspection processes without the consumer having to identify the precise breakdown in the plant’s procedures. Res ipsa allows the plaintiff to establish a prima facie case of breach and avoid summary judgment. (In many jurisdictions, the same facts would also support a strict products liability claim.)

Category-Specific Applications

Because res ipsa loquitur is so heavily fact-dependent, it helps to recognize common categories of MBE fact patterns where it is likely to be relevant.

Medical Malpractice

Key Term: Medical Malpractice
A negligence claim in which a patient alleges that a health-care provider failed to use the level of care and skill that a reasonably competent provider in the same specialty would use in similar circumstances.

Typical res ipsa medical scenarios:

• Foreign objects left inside a patient (sponges, clamps, instruments).
• Injuries to body parts remote from the surgical site (e.g., a broken arm in a patient undergoing abdominal surgery).
• Burns or nerve damage occurring while the patient is unconscious and entirely under the medical staff’s control.

In these cases:

• The first element is supported either by common sense (sponges are not normally left inside patients) or by expert testimony that such injuries rarely occur absent negligence.
• The defendant or defendants (surgeons, anesthesiologists, nurses, hospital) are the only ones who could have caused the harm at the relevant time.
• The patient, being unconscious or heavily sedated, did not contribute.

Courts are particularly willing to apply res ipsa where:

• The patient is unable to identify which of several medical professionals was responsible.
• The medical profession is in a much better position than the patient to know what went wrong.

On the MBE, if a patient suffers an unexpected injury under anesthesia and there is no direct explanation of what any one provider did, suspect that res ipsa is being tested.

Products Liability

Key Term: Products Liability
The body of law that allows plaintiffs injured by defective products to recover under theories such as negligence, strict liability, and breach of warranty.

Common res ipsa products patterns:

• A sealed can of food contains glass, metal, or some other foreign object.
• A sealed bottle of beverage explodes while being opened or handled in a normal way.
• A new packaged product fails catastrophically on first normal use (e.g., a chair collapses when first sat on).

In such cases:

• The accident is of a type that generally does not happen absent negligence by someone in the manufacturing or packaging process.
• The manufacturer (and sometimes the bottler or packer) had control at the time of the likely negligence.
• The consumer used the product in an ordinary, foreseeable way and did not contribute.

Note that many jurisdictions would also recognize strict products liability in such situations. On the MBE, however, a question may be framed purely as a negligence problem, and res ipsa may be the mechanism by which the plaintiff proves negligent manufacture or packaging.

Premises Liability

Key Term: Premises Liability
Negligence liability imposed on owners or occupiers of land for injuries caused by unsafe conditions or activities on their property.

Typical premises res ipsa scenarios:

• Elevators that suddenly drop or surge.
• Escalators that suddenly reverse or stop violently.
• Automatic doors that close on patrons.
• Heavy fixtures or signs falling from walls or ceilings.

In such cases:

• The business or property owner has a nondelegable duty to maintain those instrumentalities in safe condition.
• Malfunctions or failures of this sort do not ordinarily happen if reasonable inspection and maintenance procedures are followed.
• The injured person is typically a business invitee using the premises in a normal way.

If the fact pattern emphasizes that the property owner hired an independent contractor to service the elevator or doors, remember that the nondelegable duty means the owner is still treated as “in control” for res ipsa purposes.

Transportation and Falling Objects

Another recurring pattern:

• Parts of aircraft or trains falling onto people or property.
• Cargo falling from trucks or trains in circumstances suggesting improper securing.
• Items falling from construction sites onto passersby.

Often, members of the public cannot know exactly how or why the object fell, but can say that such objects do not ordinarily fall when due care is used. If the defendant was in control of the instrumentality (for example, the airline operating the plane), res ipsa allows an inference of negligence.

Worked Example 1.10

A pedestrian is walking in a park when a large wheel assembly detaches from a passing commuter train and rolls onto the path, injuring the pedestrian. The commuter rail company offers no explanation for the detachment. The pedestrian sues the rail company for negligence. There is no direct evidence of improper maintenance, nor any evidence of vandalism or tampering. Can the pedestrian rely on res ipsa loquitur?

Answer:
Yes, the pedestrian can invoke res ipsa loquitur to establish an inference of negligence.

First, train wheels and large assemblies do not ordinarily detach from moving trains and roll into public areas if those responsible for maintenance exercise reasonable care. Jurors can infer from common experience (supplemented, if necessary, by expert testimony) that such a failure implies negligent inspection, maintenance, or assembly.

Second, the rail company, through its employees or contractors, had exclusive or effective control over the train’s maintenance and operation at the time of the likely negligence. Members of the public had no role in attaching or inspecting the wheel assembly.

Third, the pedestrian played no part in causing the detachment; he was simply present in the park.

Because all three traditional elements are met, a reasonable jury may infer negligence by the rail company even in the absence of direct proof of a specific maintenance error. Res ipsa therefore allows the pedestrian to defeat any motion for summary judgment or directed verdict that argues “no evidence of negligence.”

Practical Exam Tips

On MBE fact patterns, look for these recurring clues that res ipsa loquitur is being tested:

• The plaintiff cannot describe what the defendant did wrong; there is “no evidence” of the defendant’s specific conduct.
• The accident involves an instrumentality usually controlled by the defendant (e.g., barrel, elevator, surgical instrument, automatic door, sealed food product).
• The question involves a motion for directed verdict, judgment as a matter of law, JNOV, or summary judgment based on “lack of evidence of negligence.”
• The fact pattern uses language like “this kind of thing does not ordinarily happen,” “barrels don’t just roll out of buildings,” or “sponges are not normally left inside patients.”
• The answer choices focus on whether the jury may infer negligence, whether the case can go to the jury, or whether the plaintiff has made out a prima facie case.

A simple step-by-step exam approach:

• Identify the type of accident and ask: Is this the kind of accident that ordinarily does not occur without negligence?
• Ask who had control over the instrumentality at the likely time of negligence.
• Consider whether the plaintiff’s own conduct is a plausible primary explanation for the accident.
• Pay attention to the jurisdictional clues about presumptions or burden shifting; if none are given, assume a majority permissive-inference rule.
• Eliminate answer choices that:
  • Treat res ipsa as imposing strict liability.
  • State that res ipsa guarantees plaintiff’s success.
  • Require the plaintiff to prove the specific negligent act under res ipsa (that contradicts the doctrine’s core purpose).

Revision Tip: Practice rewriting fact patterns in your own words: “We do not know what defendant did, but [this unusual accident] + [defendant controlled the thing] + [plaintiff did nothing unusual] = jury may infer negligence.” If you can mentally fit the facts into that template, res ipsa is likely being tested.

Key Point Checklist

This article has covered the following key knowledge points:

• Res ipsa loquitur (“the thing speaks for itself”) is an evidentiary doctrine allowing negligence to be inferred from the accident itself when direct evidence of breach is lacking.
• The doctrine does not create a separate tort or automatic liability; it is simply one method of proving the breach element in a negligence claim.
• Res ipsa operates through circumstantial evidence; the jury is asked to infer negligence from the nature and circumstances of the event.
• Traditional elements require that:
  • The accident is of a kind that ordinarily does not occur in the absence of negligence.
  • The instrumentality was under the defendant’s exclusive (or effective) control at the time of probable negligence.
  • The plaintiff did not voluntarily contribute to the occurrence in a way that is a likely primary cause.
• The first element looks to probability, not certainty: the plaintiff need not eliminate all non-negligent causes, only show that negligence is the more likely explanation for this type of accident.
• In technical or specialized contexts, expert testimony may be used to establish that the accident is the kind that ordinarily does not occur without negligence.
• The “exclusive control” element connects the likely negligence to the defendant; modern law looks to effective control or membership in a responsible “class of actors” rather than literal exclusivity.
• Nondelegable duties (such as a business’s duty to maintain safe premises) mean that a defendant may be treated as “in control” even when an independent contractor does the actual work.
• The plaintiff’s contribution element is applied flexibly in comparative-fault jurisdictions; minor plaintiff negligence usually affects damages rather than the availability of res ipsa.
• In contributory negligence jurisdictions, proven plaintiff negligence may bar recovery entirely, even if res ipsa is available to prove the defendant’s negligence.
• Modern trends relax the exclusive-control requirement, especially in medical malpractice and products liability cases, and use the Third Restatement’s “class of actors” approach.
• In some medical malpractice cases involving unconscious patients and multiple providers, res ipsa may support an inference against all providers and may, in a minority of jurisdictions, shift the burden of persuasion to them, resulting in potential joint and several liability.
• The doctrine’s main procedural effect is evidentiary: it creates a permissive inference of negligence and allows the plaintiff to avoid a directed verdict, JNOV, or summary judgment despite lacking direct evidence of breach.
• In the majority rule, res ipsa loquitur does not shift the ultimate burden of persuasion; the plaintiff still must prove negligence by a preponderance of the evidence.
• A minority of jurisdictions treat res ipsa as creating a rebuttable presumption that shifts the burden of production—and rarely the burden of persuasion—to the defendant.
• Res ipsa loquitur must be distinguished from strict liability (which does not require proof of negligence) and negligence per se (which uses statutory violations to define breach).
• Fact patterns involving surgical sponges, unexplained injuries under anesthesia, exploding bottles, foreign objects in sealed food, falling objects from buildings, and malfunctioning automatic doors are classic contexts for applying res ipsa on the MBE.
• Res ipsa is generally inappropriate where:
  • The accident is a routine event such as an ordinary car crash with known negligent conduct.
  • The accident is equally consistent with non-negligent causes, such as sudden emergencies or natural events.
  • The plaintiff’s own misuse of the instrumentality is a more likely explanation of the harm.
  • Detailed direct evidence of the defendant’s conduct is already available.
• Comparative or contributory negligence rules still apply; res ipsa does not override these defenses but may coexist with them.
• Procedural posture clues—especially motions for directed verdict, judgment as a matter of law, JNOV, or summary judgment—are strong signals that res ipsa may be the key issue.
• On the MBE, correctly answering res ipsa questions often depends on recognizing that circumstantial evidence alone can establish a prima facie case of negligence and defeat a defendant’s “no evidence of negligence” motion.

Key Terms and Concepts

• Res Ipsa Loquitur
• Circumstantial Evidence
• Direct Evidence
• Evidentiary Doctrine
• Inference of Negligence
• Exclusive Control
• Nondelegable Duty
• Directed Verdict (Judgment as a Matter of Law)
• Summary Judgment
• Judgment Notwithstanding the Verdict (JNOV)
• Prima Facie Case
• Burden of Proof
• Burden of Production
• Burden of Persuasion
• Rebuttable Presumption
• Class of Actors
• Comparative Negligence (Comparative Fault)
• Contributory Negligence
• Strict Liability
• Abnormally Dangerous Activity
• Negligence Per Se
• Joint and Several Liability
• Medical Malpractice
• Products Liability
• Premises Liability