Product liability cases involve complex technical questions that juries cannot answer without specialized knowledge. Expert witnesses provide the scientific, engineering, and medical testimony necessary to prove defects exist and caused injuries. Understanding how experts function in product cases helps you appreciate what's required to build a winning claim.
Why Expert Witnesses Are Essential
Product defects aren't always obvious. Was a weld defective, or did it fail from improper use? Did a design create unreasonable danger, or was the injury unforeseeable? Expert testimony translates complex technical issues into terms juries can understand and evaluate.
Courts require expert testimony on technical matters where ordinary experience doesn't provide a sufficient basis for judgment. In most product cases, you cannot reach the jury without expert evidence on defect and causation.
Types of Expert Witnesses
Design engineers analyze whether product designs are unreasonably dangerous and whether safer alternative designs were feasible. They compare the product to industry standards, similar products, and engineering best practices.
Materials scientists and metallurgists examine failed components to determine why they broke. Metal fatigue, improper heat treatment, contamination, and manufacturing flaws all leave distinctive evidence.
Human factors experts analyze how people interact with products, whether warnings and instructions are adequate, and whether foreseeable misuse should have been anticipated.
Medical experts connect defects to injuries, explaining how the product caused the specific harm alleged. Biomechanical engineers may analyze injury mechanisms in accident cases.
Economists calculate damages—lost wages, future earning capacity, and the cost of future medical care.
Qualification Requirements
Expert witnesses must be qualified by knowledge, skill, experience, training, or education to offer opinions in their field. Experts need not be the foremost authorities, but must have sufficient expertise to assist the jury.
Qualifications typically include advanced degrees in relevant fields, years of practical experience, publications and research, and recognition by professional organizations.
The Daubert Standard
Federal courts and many state courts apply the Daubert standard for admitting expert testimony. Judges act as gatekeepers, excluding unreliable expert opinions. Under Daubert, expert opinions must be based on sufficient facts or data, be the product of reliable principles and methods, and reflect reliable application of those methods to the facts.
Courts consider whether the expert's theory can be and has been tested, whether it has been peer reviewed and published, its known or potential error rate, and whether it is generally accepted in the relevant scientific community.
What Experts Must Prove
Product liability experts typically must establish a defect existed (the product was unreasonably dangerous), the defect existed when the product left the defendant's control, the defect caused the plaintiff's injury, and the extent of damages.
Experts often testify about what the manufacturer should have done differently—alternative designs that would have been safer, warnings that should have been provided, or quality control measures that would have caught the defect.
Challenging Defense Experts
Manufacturers retain their own experts to dispute defect and causation claims. Effective cross-examination and rebuttal testimony are crucial for countering defense experts. Common defense arguments include the product met all applicable standards, no defect existed, the plaintiff misused the product, and the alleged defect didn't cause this injury.
Your attorneys must be prepared to challenge these opinions through Daubert motions, cross-examination, and competing expert testimony.
Cost of Expert Testimony
Expert witnesses are expensive. Fees of $300-$600 per hour for consultation and testimony are common, with total expert costs in complex cases reaching tens or hundreds of thousands of dollars.
This cost is one reason product liability cases are typically handled on contingency—attorneys advance expert costs and are only reimbursed if the case succeeds. The investment in quality experts often determines case outcomes.
Working with Your Attorney
Your role in expert testimony involves providing complete, accurate information about the accident, your injuries, and their effects on your life. Preserve all physical evidence so experts can examine it. Be thorough in documenting symptoms, treatment, and limitations.
Your attorney will identify appropriate experts, work with them to analyze the case, and present their testimony effectively. The right experts—properly prepared and presented—are often the difference between winning and losing.