5 Must-Ask Questions When Choosing a Product Liability Expert


Product Liability Expert WitnessIn the world of product liability cause of actions, an expert witness can make or break the case. Product liability lawsuits, the legal liability of a manufacturer for selling a defective product, are as broad as the products themselves. Generally, in product liability cases, a plaintiff must prove that: 1) the product was defective or unreasonably dangerous; 2) the product’s defective condition existed at the time it left the domain of the defendant; and 3) the product’s defective condition was a proximate cause of plaintiff’s injuries.

The number or products that can be subjected to a lawsuit are limitless. But some are more frequently litigated than others. Automobiles, children’s products, medical devices, household appliances, chemicals, food, and industrial machinery top the list as the most common products to face lawsuits.

1) What Kinds of Experts are Needed?

Oftentimes, several types of experts are needed in a products liability case. The technical details and design of a product are best handled by an engineer in the field. Which of course, depends on the product at issue. Mechanical engineering experts may testify to the mechanical structure, design, and failure of the product. Similarly, metallurgical engineers study the design and processing of metals. This may be useful in any product that is constructed with those materials; from automobiles to kitchen appliances. Even in the cases of food products, a food science expert can be used to testify to the processing, testing, and quality control of mass-produced food.

As to causation, a biomechanical/biomedical engineering expert is pivotal in proving how the defective product caused the plaintiff’s injuries. These engineers are trained in the study of the effect of external and internal forces on the movement of the body and internal stresses and deformations of biological tissue. This type of testimony is often used in cases involving automobiles, children’s products, and medical devices. Because biomechanics experts often possess both engineering and medical degrees, their testimony can help explain the actual defect of the product. As well as how it proximately caused the plaintiff’s injury.

Product liability cases frequently revolve around the technical details of a product. However, it is important to also utilize a human factors expert to explain how people interact with the product. Human factors experts study the effects of products on individuals. They take into account the real-life issues of perception, attention, memory, and risk.

2) What is the Expert’s Experience with the Product?

In order for expert witnesses to present the most compelling testimony in a product liability case, they need experience both in and outside the courtroom. As should always be the requirement, the expert needs to have experience testifying in court; particularly in light of the technical and complex nature of the topics at issue. More so, the expert needs to be able to convey scientific terminology in layman’s terms so that a jury understands the underlying points of the testimony. A seasoned expert witness will be able to thoroughly and efficiently explain the details of a product’s structure and design; without unnecessarily confusing or burdening the jury with information that is beyond its purview.

However, it is equally important to obtain an expert witness that has experience handling and studying the product. Not just testifying about it. Because the credibility of an expert witness is fundamental (particularly experts for the defense as the defendants in product liability cased are oftentimes large corporations and thus, not as favored by a jury), it is important to obtain an expert witness that has both a technical and academic background. An expert witness that has studied, handled, researched, and written about the product at issue will be more likely to gain credibility with a jury.

3) Can the Expert Prove the Defect?

There are three general types of product defects each with its own standard of liability – manufacturing defects, design defects, and failure to warn. A product contains a manufacturing defect when the product departs from its intended design. Therefore, if alleging a manufacturing defect, an expert witness would need to testify to whether the product deviated from the manufacturer’s design and if such deviation caused the injuries.

In contrast, a design defect occurs when the entire product range is defective by design. A design defect can be proven by either the risk-utility test, when the foreseeable risks of harm could have been reduced by a reasonable alternative design; or the consumer expectations test, which allows the jury to assess the defect based on their own experiences as consumers. In either test, an expert witness should be utilized to testify as to the technical issues of cost, practicality, risk, and benefit when assessing the design.

Lastly, a failure to warn case must prove that the product was defective because of inadequate warnings. And that the foreseeable risks of harm could have been reduced or avoided by reasonable instructions. Expert witnesses are particularly useful in explaining the warnings and risks of more complex products and machinery of which a typical layperson would be unaware.

4) Can the Expert Testify as to Alternative Design or Warning?

If a products liability case centers on a design or failure to warn defect; it is important for an expert witness to be able to offer an alternative. Some jurisdictions, such as New York, require that the availability of a safer design be proven in a design defect claim. Regardless, it is always wise to have an expert that can attest to design alternatives; so that a jury may better conceptualize the defect.

In jurisdictions that use the risk-utility test for design defects, the expert may need to go beyond alleging safer design alternative and actually conduct testing and studies. Such as in the consumer expectations test, alleging an alternative design is simpler, as an expert may theorize possibilities to the jury. With regard to failure to warn cases, it is critical that an expert witness can explain not only why the warning was inadequate; but also how the harm could have been ameliorated with proper instructions. The exact proof requirements differ throughout jurisdictions. But it is still important for an expert witness to provide alternative warnings to the jury. So that they may better understand why the product’s warning was deficient.

5) What is the Expert’s Deposition History?

Particularly when utilizing expert witnesses that are experienced in testifying, it is important to review the expert’s deposition history. As is the case with any witness, they may be easily impeached by having their own previous words used against them by opposing counsel. But with product liability cases, it is particularly important to become familiar with the expert’s previous testimony. Including all of the necessary technical and scientific information. If fully informed of the expert’s previous admissions, it is easier to prepare for cross-examination by opposing counsel. And if necessary, rehabilitate the expert.

Overall, product liability cases can be quite complex and extensive in nature. Even the most seemingly straightforward, simple consumer product may present technical issues that require expert witness testimony. In light of the nearly limitless troves of information surrounding a product’s design, it’s critical an expert witness is utilized.

About The Author

Anjelica Cappellino, J.D. is an accomplished defense attorney and legal writer who has represented numerous federal criminal defendants in the Southern and Eastern Districts of New York.