Summers v. Tice vs. Sindell v. Abbott Laboratories
A side-by-side comparison of two landmark torts cases
Summers v. Tice
33 Cal. 2d 80, 199 P.2d 1 (1948) (1948)
Holding
The court held that when all defendants acted negligently toward the plaintiff and the plaintiff cannot reasonably determine which defendant caused the injury, the burden of proof on causation shifts to each defendant. Each defendant must prove that his negligent act was not the cause of the plaintiff's injury; if neither can do so, both are held jointly and severally liable.
Doctrine Established
Alternative Liability / Burden-Shifting on Causation
Sindell v. Abbott Laboratories
26 Cal. 3d 588, 607 P.2d 924 (1980) (1980)
Holding
The court held that when a plaintiff cannot identify the specific manufacturer of a product that caused injury, each manufacturer of a substantial share of the market may be held liable for its proportionate share of the judgment. Each defendant's liability corresponds to the likelihood that it produced the particular product that caused the plaintiff's injury, as measured by its share of the relevant market.
Doctrine Established
Market Share Liability
Comparison Analysis
Summers v. Tice (1948) and Sindell v. Abbott Laboratories (1980) both address the causation problem that arises when the plaintiff can prove that a tortious act caused injury but cannot identify which of multiple defendants actually caused the harm. Summers held that when two hunters simultaneously fired in the plaintiff's direction and one pellet struck his eye, the burden of proof on causation shifts to the defendants -- each must prove that they were not the cause, or both are liable. Sindell confronted a much larger-scale version of the same problem in the DES litigation, where the plaintiff could prove that her mother took the drug DES during pregnancy and that DES caused her cancer, but could not identify which of dozens of manufacturers produced the specific pills her mother consumed.
Summers solved the identification problem through burden-shifting: since both defendants acted tortiously and one of them caused the harm, it would be unjust to let both escape liability simply because the plaintiff cannot determine which one. This works when the number of defendants is small and each defendant's probability of having caused the harm is substantial. Sindell confronted a situation where Summers's approach was impractical -- there were dozens of potential defendants and the plaintiff could not join them all. The California Supreme Court created the market share liability theory, holding each manufacturer liable in proportion to its share of the relevant market.
Market share liability represents a dramatic departure from traditional causation principles, which require the plaintiff to prove that a specific defendant caused the specific harm. Sindell justified the departure on policy grounds: pharmaceutical manufacturers profit from the sale of dangerous products, and it is more fair to allocate liability based on market share than to deny recovery entirely to plaintiffs who cannot identify the specific manufacturer. The doctrine has been adopted in some jurisdictions but rejected or limited in many others, and its applicability has generally been confined to the DES context or similar situations involving fungible products.
Similarities
- Both address the identification problem in tort causation: the plaintiff knows a tortious act caused the injury but cannot identify which defendant's act was the actual cause
- Both shift some aspect of the causation burden away from the plaintiff to prevent injustice when identification is impossible through no fault of the plaintiff
- Both involve situations where all defendants engaged in tortious or unreasonable conduct that created the risk of the type of harm suffered
- Both are leading cases on alternative theories of causation taught in every Torts course
Differences
- Summers involved only two defendants with roughly equal probability of having caused the harm, while Sindell involved dozens of manufacturers with varying market shares
- Summers shifted the full burden of proof to each defendant (prove you did not cause it or be fully liable), while Sindell allocated liability proportionally based on market share
- Under Summers, each defendant faces potential full liability; under Sindell, each defendant is liable only for its proportional share
- Summers has been widely adopted across jurisdictions, while Sindell's market share liability has been accepted in only a limited number of states and contexts
- Summers requires all potential tortfeasors to be before the court, while Sindell allows recovery even when not all manufacturers are joined, so long as a 'substantial share' of the market is represented
Why This Comparison Matters
Causation questions involving multiple potential tortfeasors appear regularly on Torts exams. The critical analytical step is determining which causation theory applies. If there are two defendants who both acted tortiously and one caused the harm, apply Summers's burden-shifting approach. If there are many potential defendants producing a fungible product and the plaintiff cannot identify the specific manufacturer, consider Sindell's market share liability. Students should also discuss the policy arguments for and against each approach, including concerns about fairness to individual defendants who may not have caused any harm to the specific plaintiff.
More Torts Comparisons
Palsgraf v. Long Island Railroad Co. vs. United States v. Carroll Towing Co.
Palsgraf v. Long Island Railroad (1928) and United States v. Carroll Towing (1947) are the two most important negligence cases in American tort law, each addressing a different element of the negligence analysis. Palsgraf, through the famous Cardozo-Andrews debate, addresses the duty and proximate cause elements, holding that a defendant owes a duty of care only to foreseeable plaintiffs -- those within the zone of danger created by the defendant's conduct. Carroll Towing, through Judge Learned Hand's algebraic formula (B < PL), addresses the breach element, providing a framework for determining whether a defendant's conduct fell below the standard of reasonable care by comparing the burden of precaution (B) against the probability of harm (P) multiplied by the gravity of the resulting injury (L).
MacPherson v. Buick Motor Co. vs. Greenman v. Yuba Power Products, Inc.
MacPherson v. Buick Motor Co. (1916) and Greenman v. Yuba Power Products (1963) represent the two great revolutions in products liability law. MacPherson, authored by Judge Cardozo, eliminated the privity requirement in negligence, holding that a manufacturer owes a duty of care not just to the immediate buyer but to all foreseeable users of the product. Greenman, authored by Justice Traynor, went further by establishing strict products liability, holding that a manufacturer is strictly liable when a defective product causes injury, regardless of negligence or contractual privity.
Vosburg v. Putney vs. Garratt v. Dailey
Vosburg v. Putney (1891) and Garratt v. Dailey (1955) are both foundational intentional tort cases that explore the minimal intent required for battery, but they present the issue in different factual contexts that illuminate different aspects of the intent doctrine. Vosburg held that a schoolboy who kicked a classmate's leg during class committed a battery even though he did not intend to cause serious injury, because the kick was unlawful (it occurred during class, not during recess) and the defendant intended the physical contact. Garratt held that a five-year-old boy who pulled a chair out from under an elderly woman could be liable for battery if he knew with 'substantial certainty' that she would attempt to sit down where the chair had been.
Rylands v. Fletcher vs. Vincent v. Lake Erie Transportation Co.
Rylands v. Fletcher (1868) and Vincent v. Lake Erie Transportation Co. (1910) both involve liability imposed without fault for damage to another's property, but they rest on different theoretical foundations. Rylands established the principle that one who brings onto their land something likely to do mischief if it escapes is strictly liable for damage caused by its escape, regardless of the landowner's care or fault. This created the doctrine of strict liability for abnormally dangerous activities. Vincent held that a ship owner who kept his vessel moored to a dock during a storm to save the ship from destruction was privileged to do so (necessity) but was still liable for the resulting damage to the dock.