In negligence-based product liability, which test determines whether a product has a defect?

In negligence-based product liability, which test determines whether a product has a defect?

• A. Res ipsa loquitur
• B. Parol Evidence Rule
• C. Hand Formula
• D. Consumer expectation or Risk-Utility

Answer: (D)

In negligence-based product liability, defect is determined using either the consumer expectations test or the risk-utility test. The consumer expectations test asks whether the product performed in a way that an ordinary consumer would expect; if it didn’t, the product is defective. The risk-utility test weighs the product’s risks against its benefits and costs to reduce risk; if the risks outweigh the benefits, the design or manufacture is defective. Either approach can establish a defect, depending on the facts and jurisdiction. Res ipsa loquitur is about proving negligence through circumstantial inference when the accident typically wouldn’t happen without negligence, not about identifying product defects. The Parol Evidence Rule governs contract interpretation and integration, not product defect analysis. The Hand Formula (the B < P × L test) is a general negligence standard for duty and breach, not the specific defect-determination framework used in product liability.

In negligence-based product liability, defect is determined using either the consumer expectations test or the risk-utility test. The consumer expectations test asks whether the product performed in a way that an ordinary consumer would expect; if it didn’t, the product is defective. The risk-utility test weighs the product’s risks against its benefits and costs to reduce risk; if the risks outweigh the benefits, the design or manufacture is defective. Either approach can establish a defect, depending on the facts and jurisdiction.

Res ipsa loquitur is about proving negligence through circumstantial inference when the accident typically wouldn’t happen without negligence, not about identifying product defects. The Parol Evidence Rule governs contract interpretation and integration, not product defect analysis. The Hand Formula (the B < P × L test) is a general negligence standard for duty and breach, not the specific defect-determination framework used in product liability.