Editor's Note: For brevity, "comparative fault" is used interchangeably with "comparative negligence" in this article.

An affirmative defense is generally an argument by a defendant that goes like this: "Everything you claim may be true, but we still win because of [fill in the blank]."¹ Comparative fault² by the plaintiff (the subrogator's insured) is a great example of such a defense: even if the defendant was negligent (or strictly liable) and caused an accident, fault by the plaintiff can reduce your claim or even bar it. 

Comparative fault is a common defense in products liability claims. In this article, we'll discuss several recent products opinions in which courts addressed the defense of comparative fault. In addition, we will address the Restatement of the Law Second, Torts³ and the Restatement of Law Third, Torts – Products Liability.⁴ My hope is that the reader will be able to use this article in evaluating current and future products liability cases in which comparative fault by the claimant, including a subrogator's insured, is argued by the defendant.

The American Law Institute publishes restatements of law in many areas, including torts, in order to "clarify, modernize, and otherwise improve the law."⁵ While courts are not bound by the ALI's restatements, they frequently give great weight to them. Even though the most recent restatement text on products liability was published in 1998⁶ (Restatement Third), many courts still cite to the Restatement Second, which was published in 1965.