During the litigation of products liability cases, it is standard practice for the manufacturer or retailer to answer discovery and indicate its intent to offer evidence that the instant lawsuit is the first claim against the defendant for the product in question. The absence of other claims is often proffered to show that the defendants were not negligent, or that the product is not defective or that there is no causal relationship between the product’s design and injury causation. More often than not this evidence should be excluded because the defendant is unable to provide convincing evidence that it has in place an adequate means of identifying or learning of the product’s actual safety history. And, even if this self-serving information is proffered, it remains inadmissible absent proof that the product’s use or failure was the same as the circumstances in the instant case.

There is a developed body of case law addressing the exclusion of evidence of the absence of other similar incidents (OSIs) in a products liability action. Generally, evidence of the lack of similar incidents to prove a lack of fault or defect has less probative value than the occurrence of similar incidents because the lack of injury does not prove safety. See Ohlbaum, Edward D., Ohlbaum on the Pennsylvania Rules of evidence Section 401.10 (2013-2014 ed.). See also, Lai v. Sagle, 373 Md 306, 323, 818 A.2d 237, 248 (2003). The Pennsylvania Supreme Court has observed that “if the evidence is no more than testimony that no lawsuits have been filed, no claims have been made or that the defendant has never heard of any accidents, the trial judge should generally refuse such evidence since it has little probative value and has a high danger of prejudice.” See Spino v. John S. Tilley Ladder, 548 Pa. 286, 295 n.8 (1997). Because this sort of testimony can be highly prejudicial, courts require that a defendant lay a sufficient foundation to prove that the manufacturer/retailer has developed and consistently employed a robust method to to learn of the existence of prior substantially similar accidents before allowing any mention of the absence of such incidents. And that method has to be much more than testimony that the defendant has not been previously sued. Evidence of the absence of prior accidents is “permissible only if it relates to other accidents happening at substantially the same place and under the same conditions as those involved in the action on trial.” See DiBuono v. A. Barletta & Sons, 560 A.2d 893, 896 (Pa. Commw. 1989) (citation omitted).