In a product liability claim, expert witnesses may be helpful in proving that a product is defective or that the product caused injuries. For example, a company may claim that the plaintiff’s injuries were caused by the plaintiff’s own misuse of the product, rather than any defect. An expert witness could testify as to why and how the plaintiff’s injuries were caused by the product. Expert witnesses are not necessary for every case, and it will depend on the facts of the case and what the plaintiff is alleging. A competent lawyer will know when to call for an expert witness and what type of expert witness to call.