lead levels, from which “a jury could reasonably infer that if [defendant’s property] was not contributing source [of lead exposure,]” plaintiffs blood lead levels would have decreased while living at that property). And, of course, a plaintiff who overcomes summary judgment still bears the burden of proof as to the element of causation at trial, where expert opinion can play a critical role in persuading a jury. The standard for admissibility of expert testimony as to source causation is thus a vital one in lead paint actions. The Majority holds today that an expert who gives an opinion that a defendant’s property caused a plaintiffs harm does not need to show or explain that other reasonably probable sources did not cause the plaintiffs harm. Majority Op. at 250-51, 164 A.3d at 238 (<HOLDING>) The Majority’s removal of the requirement that
holding that the district court did not abuse its discretion in allowing plaintiffs expert witness to testify when it also allowed defendants expert witness who disputed the methodology used by plaintiffs expert to testify holding that an expert is not competent to testify as to statutory interpretation holding that an expert witnesss testimony on an ultimate issue was admissible recognizing that the expert did not specifically testify that the defendant was guilty or that as a matter of law the facts satisfied the applicable legal standard holding that it is not the rule that a source causation expert in a lead paint action must exclude other properties before he can testify that the plaintiff was exposed to lead at the subject property recognizing that a plaintiff must produce a medical expert to testify as to causation in all but the most selfevident medical malpractice actions