Expert Witness Blog
Appeals court affirms opinion of district court that experts’ testimony was not scientifically reliable. However, the court does set precedent on differential diagnoses to support general and specific causation.
Facts: This case (C.W. and E.W., by Guardians and Next Friends Adele A. Wood and Jason A. Woon v. Textron, Inc- United States Court of Appeals For the Seventh Circuit – August 26th, 2015) involves the exposure of vinyl chloride (a carcinogen, mutagen, and genotoxin) to two infant children. Textron challenges the three environmental toxicology expert witnesses brought forth by the Woods’.
Textron operated a fastener manufacturing plant from 1954 to 2006. At some point during this time, the plant released vinyl chloride, which seeped into the groundwater and contaminated nearby residential wells. One of the wells was owned by the Woods. While living in their house their two adopted children experienced various gastrointestinal symptoms, including vomiting and bloody stools, and other immunological and neurological issues. After moving to a new house, their symptoms decreased and their health improved.
The Woods then sued Textron in Fulton County Circuit for negligence, negligence per se, and negligent infliction of emotional distress. The case was removed to federal court. In order to succeed on causation grounds, the Woods’ need to present evidence on specific (whether the substance caused the harm) and general causation (whether the substance had the capacity to cause the harm) and Textron subsequently filed motions to exclude the testimony of the three expert witnesses that were opining on these two forms of causation. The district court agreed with Textron and ruled that the testimony should be excluded on reliability grounds.
Discussion: The appellants offered the testimony of Drs James G Dahlgren, Dr. Vera S. Byers, and Dr. Jill E. Ryer-Powder. Dr. Dahlgren provided an expert report concluding that the vinyl chloride can cause and did cause the illnesses, basing these conclusions on differential etiology. This type of scientific causation approach involves the elimination of other possible causes for the illness to come to the conclusion that the only one not eliminated was the cause. His findings were based on other doctors’ examinations of the children as well as scientific studies.
The district court pointed to Gen. Elec. v. Joiner (522 U.S. 136), a U.S. Supreme Court opinion, which stated that nothing in Daubert or the Federal Rules of Evidence requires a court to admit opinion evidence which is connected to data only by the “ipse dixit” of the expert. If there is too great a gap between the data and the opinion offered, the testimony should be excluded.
Dr. Byers expert testimony falls into the same trap. She used differential diagnosis to come up with her conclusions that the vinyl chloride could and did cause the childrens’ symptoms and illnesses. The court excluded her testimony based on the same reasoning at Dr. Dahlgren, that of the failure to bridge the gap between the studies of causation and the illnesses of the children.
Dr. Ryer-Powder relied on regulatory exceedances to form her opinion on causation. This means that by looking at the standards and regulations of how high certain levels of toxicity should be, and then comparing them to the levels found at the specific area, one can prove possible causation. She also looked at studies in this area. The district court excluded her methodology in that it did not offer a reliable basis to support her opinion.
The appeals court looked at the district court opinion and concluded that they were in the realm of their authority to exclude the testimony. There was too great of analytical gap between the data and the opinion offered. The appellants argue that there are no studies available on the impact on vinyl chloride on children as they would cause ethical and moral concerns. The appeals court points out that there is a work-around to this, using computer based models to extrapolate data from animal studies to humans. The appellants did not utilize these models to prove their case, and affirmed the opinion of the district court on all grounds.
That said, they did disagree with the district court, that of always excluding differential etiology as a method to establish general causation. The appeals court states that there may be cases where general and specific causation can be proven by this method, pointing to a Second Circuit opinion that has taken this approach.
Held: The opinion of the district court to exclude the testimony of the experts is confirmed.