A product liability lawsuit may be based on a flaw in the design of the product. A design defect refers to when a danger associated with a product should have been foreseen and the risk associated with it could have been reduced or eliminated had a reasonable alternative design been used. While a lawsuit claiming a manufacturing error focuses on mistakes in the process of making a product, a case claiming a design defect alleges errors in the plans themselves. In a product liability lawsuit alleging a defect in design, the plaintiff must first prove that an alternative design would make the product safer and then show that the alternative is both practical and cost-efficient.