Holding that expert testimony was inadmissible based on its unreliable methodology notwithstanding "the impressive qualifications of plaintiffs' experts"
Holding that "[r]ulings on admissibility under Daubert inherently require the trial court to conduct an exacting analysis of the proffered expert's methodology"
Holding that, in order to avoid summary judgment, the plaintiffs in a FELA action were required to produce expert testimony that exposure to chemicals played a part in causing their injuries
Holding that a right to damages is substantive and governed by state law in a diversity action because the remedy "is inseparably connected with the right of action"
Holding a party's lack of explanation for why an opinion based on data acquired before the expert report was due but disclosed later in the case to be cause for excluding the expert's new analysis