You’re staring at another MBE products liability question, and you freeze. Is this a manufacturing defect or a design defect? Do you need to prove negligence, or is this strict liability? And what’s the difference between a design defect and a failure to warn? If these distinctions blur together in your mind, you’re not alone — products liability is one of the most frequently tested Torts topics on the MBE, and the examiners love to exploit the confusion between the three defect types.

Let’s fix that. This article breaks down the framework you need to spot and analyze manufacturing defects, design defects, and warning defects on exam day.

The Big Picture: Strict Liability for Defective Products

Products liability operates primarily under a strict liability regime. That means a plaintiff does not need to prove the defendant was negligent — only that the product was defective and that defect caused the plaintiff’s injury. This is a huge departure from standard negligence analysis.

Here’s the basic framework: A commercial supplier (manufacturer, distributor, or retailer) is strictly liable for selling a defective product that causes injury to a foreseeable plaintiff. The plaintiff must prove three elements: (1) the product was defective, (2) the defect existed when the product left the defendant’s control, and (3) the defect caused the plaintiff’s injury.

The key battleground is always the first element: what kind of defect are we dealing with? The three categories — manufacturing, design, and warning — each have different proof requirements and different defenses. Mixing them up will cost you points.

Manufacturing Defects: When the Product Deviates from the Plan

A manufacturing defect exists when a product departs from its intended design, making it more dangerous than consumers expect. Think of the exploding soda bottle, the car with faulty brakes that passed inspection, or the contaminated batch of medication. The product was supposed to be made one way, but something went wrong in production.

Test for manufacturing defect: Compare the product that injured the plaintiff to other products in the same line. If this particular unit differs from the manufacturer’s specifications or from identical products, it’s defective.

Here’s a classic MBE fact pattern: A consumer buys a jar of peanut butter from a grocery store. When she opens it, she discovers a shard of glass embedded in the peanut butter, which cuts her mouth. She sues the manufacturer. This is a manufacturing defect. The manufacturer didn’t intend for glass to be in the peanut butter — this jar deviated from the intended design.

Why manufacturing defects are easier for plaintiffs: The plaintiff doesn’t need to prove the defendant was careless or that the design itself was flawed. She only needs to show that this specific product was different from how it was supposed to be. The doctrine of strict liability does the heavy lifting. The defendant is liable even if it exercised all possible care in the manufacturing process.

Common MBE trap: The examiners will try to make you think about negligence. They’ll tell you the manufacturer had state-of-the-art quality control or that no other product in the batch was defective. Ignore that. If this one unit was defective when it left the defendant’s control, strict liability applies. You don’t analyze the defendant’s conduct — you analyze the product.

Design Defects: When the Entire Product Line Is Dangerous

A design defect exists when the product is manufactured exactly as intended, but the design itself is unreasonably dangerous. Every unit in the product line has the same flaw. Think of the SUV with a high center of gravity that’s prone to rollovers, or the electric heater without an automatic shutoff that causes fires.

Two tests for design defect (and yes, you need to know both):

1. Consumer Expectation Test: The product is defective if it fails to perform as safely as an ordinary consumer would expect when used in an intended or reasonably foreseeable manner. This test is subjective and focuses on consumer expectations. It’s most useful for obviously dangerous products — the exploding lawnmower, the collapsing chair.

2. Risk-Utility Test (also called the Reasonable Alternative Design test): The product is defective if the risks of the design outweigh its benefits, and a reasonable alternative design was available that would have reduced the risk without excessive cost or loss of utility. This is the more common test on the MBE. The plaintiff must show that a safer design was feasible.

Here’s how this plays out on the exam: A plaintiff is injured when his table saw kicks back and severs two fingers. He sues the manufacturer, claiming the saw should have included a blade guard that would have prevented the injury. The manufacturer argues that blade guards reduce visibility and make the saw less useful for precision cuts. This is a design defect claim under the risk-utility test. The jury must weigh the risk of injury against the cost and utility of the alternative design (the blade guard).

Key distinction from manufacturing defects: With a design defect, every product in the line has the same “flaw” — because that’s how the manufacturer designed it. The plaintiff is arguing the design choice itself was unreasonable.

Common MBE trap: The examiners will give you a fact pattern where the product is dangerous but widely used in the industry. Don’t assume that industry custom makes the design reasonable. The defendant can still be liable if a safer alternative design was feasible. Compliance with industry standards is evidence of reasonableness, but it’s not dispositive.

Warning Defects (Failure to Warn): When the Danger Isn’t Obvious

A failure to warn claim arises when the product is properly manufactured and reasonably designed, but the manufacturer failed to provide adequate instructions or warnings about non-obvious risks. The product isn’t defective in its physical form — it’s defective because it lacks necessary information.

Test for failure to warn: The manufacturer must warn of risks that are (1) not obvious or generally known, and (2) present even when the product is used as intended or in a reasonably foreseeable manner. The warning must be clear, conspicuous, and specific enough to inform users of the nature and extent of the risk.

Example: A pharmaceutical company sells a prescription drug that can cause liver damage if taken with alcohol. The drug is properly manufactured and its benefits outweigh its risks when used correctly. However, the label contains no warning about the alcohol interaction. A patient takes the drug with wine and suffers liver failure. This is a failure to warn. The risk was not obvious, and a warning could have prevented the harm.

No duty to warn of obvious dangers: A manufacturer does not need to warn that a knife is sharp, that a ladder can cause falls if misused, or that alcohol impairs driving. These are common knowledge. The MBE loves to test this — they’ll give you a fact pattern with an obvious risk and ask whether the manufacturer should have warned about it. The answer is almost always no.

Learned intermediary doctrine: For prescription drugs and medical devices, the manufacturer’s duty to warn runs to the prescribing physician, not the patient. If the doctor is adequately warned, the manufacturer has satisfied its duty — even if the doctor fails to pass the warning on to the patient. This is a minority rule but appears on the MBE.

Common MBE trap: The examiners will combine a failure to warn claim with a misuse defense. They’ll tell you the plaintiff used the product in an unforeseeable way and didn’t read the warnings. Remember: The manufacturer must warn about reasonably foreseeable misuses, not just intended uses. If teenagers are known to huff aerosol cans, the manufacturer may have a duty to warn about that risk, even though it’s misuse.

Defenses to Products Liability Claims

Even if the plaintiff proves a defect, the defendant may have defenses:

Assumption of risk: If the plaintiff knew of the defect and voluntarily encountered the risk, recovery may be barred (in jurisdictions that recognize this as a complete defense) or reduced (in comparative fault jurisdictions). The plaintiff must have actual knowledge of the specific risk — general awareness that “products can be dangerous” isn’t enough.

Comparative fault: Many jurisdictions apply comparative negligence principles to products liability. If the plaintiff’s misuse of the product contributed to the injury, damages are reduced by the plaintiff’s percentage of fault. Note that comparative fault applies to the plaintiff’s conduct, not to the defendant’s — the defendant is still strictly liable for the defect.

Product alteration: If the product was substantially altered after it left the defendant’s control, and that alteration caused the defect, the defendant is not liable. The alteration must be unforeseeable. If the defendant should have anticipated that users would modify the product (e.g., removing a safety guard), the defendant remains liable.

Unforeseeable misuse: The defendant is not liable for injuries resulting from unforeseeable misuse. But remember: Many misuses are foreseeable. Using a ladder on an icy surface, standing on the top rung, or using a hair dryer in the bathtub — all foreseeable.

Who Can Be Held Liable?

Strict products liability applies to all commercial suppliers in the distribution chain: manufacturers, wholesalers, distributors, and retailers. Even if the retailer had no role in creating the defect and no ability to inspect for it, the retailer can be held strictly liable. This is a policy choice — it ensures the plaintiff has a solvent defendant and spreads the risk across the commercial chain.

Casual sellers are generally not subject to strict liability. If you sell your used car to a neighbor and the brakes fail, you’re not strictly liable (though you might be liable for negligence if you knew about the defect and failed to disclose it).

Service providers are typically not subject to strict products liability. If a hospital provides a defective pacemaker during surgery, most courts treat this as a service (medical malpractice) rather than a product sale, and the hospital is not strictly liable for the device defect. The manufacturer of the pacemaker, however, would be strictly liable.

Putting It All Together: How to Approach Products Liability on the MBE

When you see a products liability question, follow this checklist:

  1. Identify the type of defect: Did this specific unit deviate from the design (manufacturing)? Was the entire product line unreasonably dangerous (design)? Or was the product missing necessary warnings (failure to warn)?

  2. Apply the appropriate test: Manufacturing defects use the deviation-from-design test. Design defects use consumer expectation or risk-utility. Failure to warn requires a non-obvious risk and inadequate instructions.

  3. Check for defenses: Did the plaintiff know about the defect and use it anyway (assumption of risk)? Did the plaintiff misuse the product in an unforeseeable way? Was the product altered after it left the defendant’s control?

  4. Confirm the defendant is a commercial supplier: Strict liability doesn’t apply to casual sales or (usually) service providers.

  5. Prove causation: The defect must have caused the plaintiff’s injury. If the plaintiff would have been injured even with a non-defective product, there’s no liability.

The MBE will try to blur these categories. They’ll describe a manufacturing defect but throw in language about “industry standards” to make you think it’s a design defect. They’ll give you a failure to warn scenario but tell you the plaintiff didn’t read the label, tempting you to think the defendant wins automatically. Stay disciplined. Identify the defect type first, then apply the correct rule.

What to Memorize for Exam Day

Here’s your takeaway checklist for products liability MBE questions:

If you want all 88 Torts rules organized for active recall — including the complete products liability framework, negligence elements, and intentional torts — FlashTables breaks them down in a two-column format designed for memorization under pressure. The tables eliminate the clutter and give you exactly what you need to recognize the issue and apply the rule on exam day. Check out the Torts table at getflashtables.com.

Products liability questions are point-getters if you know the framework. Nail down the three defect types, memorize the tests, and you’ll spot these issues instantly when they appear on your exam.