The Eighth Circuit excluded an expert’s opinion because the testing he relied on did not prove what he claimed that it did. In Presley v. Lakewood Engineering and Mfg. Co. 553 F3d 638 (8th Cir. 2009), Plaintiffs suffered personal injuries and there was property damage as a result of a fire which occurred during the night in their home. Defendant was a manufacturer of an oil fired space heater which plaintiffs’ expert Raymond Arms opined was the source of the fire. The expert had metallurgical testing done on evidence collected at the fire scene. Following these tests he had C&A flammability tests done on components of an exemplary heater.
Based on the testing and his own observations, he opined that a manufacturing defect in the heater caused the fire. The trial court excluded Arm’s testimony and granted defendant summary judgment.
The Court of Appeals affirmed and found that the testing was not an adequate basis for the expert theory because it was not appropriate and did not analytically prove the expert’s hypothesis. In other words, the testing did not prove what the expert claimed it proved. The Court said:
“The ignition and spread in Arm’s theory was the product of Arm’s speculation based upon his expertise analyzing the basic results of the metallurgical tests and the C & A flammability tests. An expert generally cannot formulate a theory through supposition based on his or her own expertise. See General Elec. Co. v. Joiner, 522 U.S. 136, 146, 118 S.Ct. 512, 139 L.Ed. 2d 509 (1997) (stating neither “Daubert [n]or the Federal Rules of Evidence requires a district court to admit opinion evidence that is connected to existing data only by the ipse dixit of the expert” because “[a] court may conclude that there is simply too great an analytical gap between the data and the opinion proffered”). The general bases provided by Arms for his theories did not match the complexity of the theories, and the district court did not abuse its considerable discretion in excluding Arm’s expert testimony.” (pp 646-7)