522 U.S. 166 (1997)
In 1973, Robert Joiner began work as an electrician in the Water & Light Department of Thomasville, Georgia.1 This job required him to work with and around the City's electrical transformers, which used a mineral-oil-based dielectric fluid as a coolant.2 Joiner often had to stick his hands and arms into the fluid to make repairs.3 The fluid would sometimes splash onto him, occasionally getting into his eyes and mouth.4 In 1983 the City discovered that the fluid in some of the transformers was contaminated with polychlorinated biphenyls (PCBs).5
Joiner was diagnosed with small-cell lung cancer in 1991.6 He sued petitioners in Georgia state court the following year.7 Petitioner Monsanto manufactured PCBs from 1935 to 1977; petitioners General Electric and Westinghouse Electric manufactured transformers and dielectric fluid.8 In his complaint Joiner linked his development of cancer to his exposure to PCBs and their derivatives, polychlorinated dibenzofurans (furans) and polychlorinated dibenzodioxins (dioxins).9 Joiner had been a smoker for approximately eight years, his parents had both been smokers, and there was a history of lung cancer in his family.10 Petitioners removed the case to federal court.11
Once in federal court, petitioners moved for summary judgment.12 They contended that there was no evidence that Joiner suffered significant exposure to PCBs, furans, or dioxins, and that there was no admissible scientific evidence that PCBs promoted Joiner's cancer.13 Joiner responded that there were numerous disputed factual issues that required resolution by a jury.14 He relied largely on the testimony of expert witnesses.15 In depositions, his experts had testified that PCBs alone can promote cancer and that furans and dioxins can also promote cancer.16 They opined that since Joiner had been exposed to PCBs, furans, and dioxins, such exposure was likely responsible for Joiner's cancer.17 The experts included Dr. Arnold Schecter, who testified that it was more likely than not that Mr. Joiner's lung cancer was causally linked to cigarette smoking and PCB exposure, and Dr. Daniel Teitelbaum, who testified that Joiner's lung cancer was caused by or contributed to in a significant degree by the materials with which he worked.18
The District Court ruled that there was a genuine issue of material fact as to whether Joiner had been exposed to PCBs.19 But it nevertheless granted summary judgment for petitioners because there was no genuine issue as to whether Joiner had been exposed to furans and dioxins.20 The testimony of Joiner's experts had failed to show that there was a link between exposure to PCBs and small-cell lung cancer. The court believed that the testimony of respondent's experts to the contrary did not rise above subjective belief or unsupported speculation.21 The Court of Appeals for the Eleventh Circuit reversed.22 It held that because the Federal Rules of Evidence governing expert testimony display a preference for admissibility, it applied a particularly stringent standard of review to the trial judge's exclusion of expert testimony.23 The Supreme Court granted petitioners' petition for a writ of certiorari in 1997.24
Whether abuse of discretion is the appropriate standard of review for a district court's decision to admit or exclude expert testimony under Daubert?25
Abuse of discretion is the proper standard of review of a district court's evidentiary rulings. Daubert did not alter this general rule for decisions to admit or exclude scientific evidence.26
Yes. The Court of Appeals applied a particularly stringent standard of review to the District Court's exclusion of expert testimony instead of traditional abuse-of-discretion review.27 The Supreme Court has long held that evidentiary rulings receive abuse-of-discretion review, and Daubert left the trial judge's gatekeeper role intact without changing the appellate standard.28 The District Court excluded Joiner's experts after determining that animal studies on infant mice and epidemiological studies on workers did not support the causation opinions linking PCB exposure to small-cell lung cancer.29
Abuse of discretion is the appropriate standard of review for a district court's decision to admit or exclude expert testimony under Daubert.30
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Justice Breyer concurs and stresses that trial judges must exercise special care when fulfilling their Daubert gatekeeping duties in toxic tort cases involving scientific evidence.31 He explains that judges, who lack scientific training, should use tools such as pretrial conferences under Rule 16, expert hearings, and appointment of independent experts under Rule 706 to evaluate complex methodology and ensure that tort liability targets the correct substances rather than destroying useful ones.32 Breyer notes the New England Journal of Medicine's offer of assistance from scientific organizations to help courts make reliable determinations.33
Whether the District Court abused its discretion when it excluded the testimony of Joiner's expert witnesses?34
No. The District Court did not abuse its discretion when it excluded the testimony of Joiner's expert witnesses.3738 The animal studies involved infant mice receiving massive PCB doses directly into their peritoneums and developing alveologenic adenomas, whereas Joiner was an adult human exposed to far lower concentrations through splashing fluid and developed small-cell lung cancer.39 The four epidemiological studies either found no statistically significant link to PCBs, involved different mineral oils, or included exposure to multiple other carcinogens.40 The experts' opinions therefore rested on an excessive analytical gap that the District Court properly rejected.41
The District Court did not abuse its discretion when it excluded the testimony of Joiner's expert witnesses.
Related opinions on this issue
Justice Stevens concurs in the standard of review but dissents from the judgment and Part III.42 He maintains that the District Court improperly attacked the experts' conclusions rather than their weight-of-the-evidence methodology, which is a scientifically acceptable approach used by the EPA and petitioners' own experts.43 Stevens argues that when qualified experts reach relevant conclusions on the basis of an acceptable methodology, their opinions should be admitted and any weaknesses tested through cross-examination and contrary evidence rather than wholesale exclusion.44
He would remand for the Court of Appeals to apply the correct standard to the full record.45