Plourde claims that she has experienced congestion and elevated white blood cell count following the 1999 incident, as well as severe mental distress and trauma. Plaintiffs Andre and Daniele Plourde allege no direct physical injuries, but claim they suffered severe mental distress and trauma and related physical symptoms and illness in connection with that stress. II. Discussion Although subject-matter jurisdiction in this case is predicated on the diversity of the parties, federal evidentiary rules control on the admissibility of an expert’s opinion on injury causation. See, e.g., McCulloch v. H.B. Fuller Co., 61 F.3d 1038, 1042 (2d Cir.1995); Campbell v. Metro. Prop. & Cas. Ins. Co., 239 F.3d 179, 184 (2d Cir.2001); see also Forrestal v. Magendantz, 848 F.2d 303, 305 (1st Cir.1988) (<HOLDING>). Federal Rule of Evidence 702 provides: If
holding that state substantive rules of decision apply in federal diversity cases holding that the federal expert witness compensation rules are in direct conflict with the state rules even when the state rules allow for a greater recovery holding that the admissibility of expert testimony was governed by state law holding that federal evidentiary rules control on questions of admissibility of expert medical witness testimony even in diversity cases holding that federal courts must apply state substantive law in diversity cases