Fixed vs. flexible neuropsychological test batteries under the Daubert standard for the admissibility of scientific evidence.

In Chapple v. Ganger, (1994), the Daubert standard was applied for the very first time to the use of fixed (standardized) versus flexible (nonstandardized) neuropsychological test batteries in the federal court. In this personal injury case the Chapple court gave far greater weight to the results obtained from a fixed battery than to the results obtained from two flexible neuropsychological test batteries. Significantly, under the Daubert standard the District Judge noted the lack of medical and scientific evidence to support the conclusions made by the Plaintiffs' two expert witnesses, a psychologist and a neuropsychologist, even though each had administered a comprehensive and flexible neuropsychological test battery and had based their conclusions on the test results. However, the Judge accepted as scientific evidence the objective test results obtained from the fixed Halstead-Reitan Neuropsychological Test Battery for Older Children administered by the Defendants' expert witness Dr. Ralph Reitan and also accepted his scientific expert medical testimony which was closely derived from these data. Applying the Daubert standard to the neuropsychological test results and opinions of the expert witnesses, the District Judge held that the entire reasoning process and not simply part of the reasoning process upon which the expert witness derives a conclusion must reflect scientific methodology.