What Evidence Is Needed to Prove a Product Is Defective in Court?

To prove that a product is defective in a legal claim, the consumer must present evidence demonstrating that the product did not function as expected, posed safety risks, or was not fit for its intended use. This evidence must establish a clear link between the defect and the harm caused.

Types of Evidence Needed

• Proof of Purchase: Receipts, invoices, or other documentation proving that the product was purchased from the retailer or manufacturer.
• Product Defect: Physical evidence of the defect, such as the malfunctioning product itself, or photographs and videos showing the defect.
• Expert Testimony: In complex cases, an expert opinion may be needed to explain why the product is defective and how it fails to meet safety or functional standards.
• Technical Reports: Reports from testing agencies or product evaluations that highlight the defect or failure in quality control.
• Warranty or Guarantee: Documentation of the warranty or guarantee terms to show that the product was expected to function properly and within a specific timeframe.
• Customer Communication: Emails, messages, or records of communication with the seller or manufacturer reporting the issue and their response (or lack thereof).
• Medical Records (if applicable): If the defect caused personal injury, medical records detailing the harm and connecting it to the product’s malfunction.

What the Consumer Must Prove

• The Product Was Defective: The consumer must prove that the defect existed either when the product was purchased or during its use, not as a result of mishandling or external damage.
• The Defect Caused Harm: The consumer must establish a direct link between the defect and the harm or injury suffered. For example, if the product malfunctioned and caused an injury, there must be a causal connection between the two.
• The Consumer Used the Product Properly: Evidence must show that the product was used as intended and according to any provided instructions or guidelines.

Legal Process

• Consumer Complaint: The consumer can file a legal complaint with the consumer court if the seller refuses to acknowledge the defect or provide a remedy.
• Expert Opinion: In court, an expert witness may be called to explain why the product was defective and how it should have functioned.
• Inspection of Product: The court may order an inspection of the defective product by an independent testing authority to verify the defect.

Example

If a person purchases a microwave from a retailer and it catches fire during normal use, the consumer should:

• Retain the receipt or proof of purchase to show that the product was bought from the retailer.
• Take photos or videos of the damaged microwave and the fire hazard to provide physical evidence of the defect.
• Provide any communication with the retailer where the defect was reported but not addressed.
• If personal injury occurred, provide medical records to show how the malfunction directly caused harm.
• If needed, involve an expert to explain how the microwave's malfunction posed a safety risk.