For referring counsel: Expert testimony product defect cases live or die at the Sargon gate. Build the expert’s methodology to survive the motion, and turn the science into something a jury can see.
Refer or co-counsel: (323) 658-8077 · [email protected]
The gatekeeper. Sargon Enterprises, Inc. v. University of Southern California (2012) 55 Cal.4th 747 confirms that California trial courts act as gatekeepers for expert testimony. The court may exclude an opinion that is speculative, that rests on assumptions without evidentiary support, or that uses an unreliable methodology. Expert testimony product defect cases must satisfy that standard on both defect and causation.
What Sargon requires
The trial court does not weigh which expert is more persuasive. It screens for reliability. The opinion must rest on matters a reasonable expert would rely on, must be based on reliable principles and methods, and must not extend those methods to unsupported conclusions. An expert who reasons from tested principles to a conclusion the data supports will clear the gate. An expert who leaps from a credential to an unexplained conclusion will not.
The experts a defect case usually needs
A typical defective-product case calls for a design or engineering expert on the defect, an origin-and-cause expert in a fire case, a human-factors or warnings expert where the claim involves a failure to warn, and an economist or life-care planner on damages. Each must be prepared to show the method, not just the conclusion.
The Shinedling science made visible
The physics was simple and powerful. A radiant quartz element runs near 1,200 degrees. Common household fabrics ignite near 450 degrees. When the advertised shutoff did not prevent contact ignition, the gap between those two numbers explained the fire. Presented as a bar chart, the science became something the jury could see in a glance. Good expert testimony product defect cases translate engineering into a picture.
Practice points
Vet the methodology before you retain, because a brilliant resume does not survive a weak method. Prepare the expert to explain each analytical step in plain terms. Anticipate the defense motion and build the reliability record in the report. And convert the key science into a demonstrative, as the temperature comparison did in this case.
Refer or co-counsel
The firm accepts defective-product referrals across California and pays a referral fee consistent with California Rule of Professional Conduct 1.5.1, with a written fee-division agreement and the client’s written consent.
The Homampour Law Firm, PC · 15303 Ventura Blvd, Suite 1450, Sherman Oaks, CA 91436
Refer or co-counsel: (323) 658-8077 · [email protected] · homampour.com
Frequently asked questions
What is the standard for expert testimony in California product cases?
Under Sargon, the trial court is a gatekeeper. It may exclude opinions that are speculative, unsupported by the evidence, or based on unreliable methods. The court screens reliability, not persuasiveness.
What experts does a defective-product case usually require?
Commonly a design or engineering expert, an origin-and-cause expert in fire cases, a warnings or human-factors expert, and an economist or life-care planner on damages.
How do you keep an expert opinion from being excluded?
Build the methodology into the report, have the expert explain each step from reliable principles to a supported conclusion, and avoid analytical gaps that invite a Sargon challenge.
Free download
The space-heater demonstrative kit is available as a PDF and an editable PPTX.
Past results do not guarantee similar outcomes. Every case is different. This page is attorney advertising and general information, not legal advice, and it does not create an attorney-client relationship.