Repeated psychiatric examinations of 42 litigants were compared to determine reasons for differences in findings by experts hired by the defendant and by the plaintiffs. The lawsuit resulted from the collapse of a coal slag heap in Buffalo Creek, W. Va., in 1972. All psychiatric reports prepared for the trial were screened. Experts for the two sides differed systematically over the extent of recovery from psychiatric symptoms and in other areas. Changes in the plaintiffs' mental statuses over time are shown not to be the cause. Extraneous factors, such as "forensic identification," the subtle influence of adversarial proceedings on initially neutral witnesses, are shown to play a part.