Practice Tip: Expert Preparation ' The Ipse Dixit Problem

Every product liability trial lawyer must make sure when preparing his/her expert for testimony that the expert does not give an opinion that is merely ipse dixit. In Joiner, the Supreme Court affirmed a lower court's decision to exclude testimony of the plaintiff's experts who opined that the plaintiff's lung cancer was caused by exposure to the defendant's transformers containing PCBs, a prohibited compound. The plaintiff claimed that PCBs contained derivatives, PCCDS, which enhanced his cancer, initiated by his smoking. The trial judge said the evidence failed to show whether the plaintiff was ever exposed to PCBs and, for that reason, precluded the expert's testimony. On appeal, the Eleventh Circuit reversed, Joiner v. General Electric Co. 78 F3d 524 (11th Cir. 1997); it found the lower court failed to use the proper standard of review, to wit: abuse of discretion. The Supreme Court reversed the appellate court and went on to say that neither Daubert nor the Federal Rules of Evidence require a district court to admit evidence that is connected to existing data only by the “ipse dixit” of the expert. Because the plaintiff's expert was missing the link in evidence that connected the PCBs to the plaintiff, his testimony was properly precluded.