Fourth circuit denies rehearing in case with major implications for Article III standing and trial court’s role as gatekeeper for expert testimony

The district court decision

The underlying case is a putative class action in the Southern District of West Virginia seeking medical monitoring for alleged increased cancer risk resulting from defendants' ethylene oxide emissions in South Charleston. Tort claims for medical monitoring based on alleged increased risk of future disease are recognized by a small minority of states. Defendants moved for summary judgment on the basis that the case was non-justiciable because the plaintiff did not allege an injury cognizable under Article III.

In a detailed opinion, District Judge Joseph Goodwin determined that the plaintiff “failed to provide any evidence of present injury beyond the speculative increase in risk” and held that “claims for medical monitoring seeking damages without a manifest injury do not satisfy the injury-in-fact requirement for Article III standing.”¹

A few months before its decision on standing, the district court also granted² the defendants' motion to strike plaintiff's expert, Dr. Ranajit Sahu, a mechanical engineer who has testified for plaintiffs in every EtO case tried to date.³  Judge Goodwin concluded that Dr. Sahu's opinions were unreliable under Federal Rule of Evidence 702 and Daubert.

Overturned on appeal

On appeal, a divided Fourth Circuit panel reversed both the district court's justiciability determination and the exclusion of Dr. Sahu under Daubert.⁴ The panel majority held that “plaintiffs properly alleging the elements of West Virginia's medical monitoring tort have Article III standing.”  Chief Judge Diaz dissented for essentially the reasons given by the district court: “an increased risk of developing cancer” is too speculative for Article III standing.

The panel also criticized the district court's Daubert analysis for reaching too far into the factual underpinnings of Dr. Sahu's opinions and addressing matters of weight and credibility, not admissibility under Rule 702.

On November 4, the court denied the defendants' petition for en banc rehearing. 

Threading the needle of expert challenges

The Fourth Circuit opinion places district courts in a difficult position. As the dissent noted, the majority effectively faults the district court for exercising the gatekeeping role commanded by Rule 702, which the Fourth Circuit in other cases has admonished district courts not to “abdicate.”

Rule 702 requires expert testimony to be “based on sufficient facts or data” and represent “a reliable application of the principles and methods to the facts of the case.” This rule was amended in 2023 specifically to address the misconception in “many courts” that “the critical questions of the sufficiency of an expert's basis, and the application of the expert's methodology, are questions of weight and not admissibility.” The advisory committee rebuffed the misconception “that arguments about the sufficiency of an expert's basis always go to weight and not admissibility.”

This tension was not lost on the district court. Indeed, Judge Goodwin expressly rejected the plaintiff's argument that the challenges to Dr. Sahu were matters of “weight and credibility” rather than admissibility under Daubert. The district court held that “the issues presented to the court deal not only with the validity of the underlying data . . . but also with Dr. Sahu's methods in applying that data to the facts of the case.” The panel majority disagreed, stating that “the district court's analysis was not a true critique of Dr. Sahu's ‘methodology,' but a veiled credibility determination.” 

What now?

In the Fourth Circuit at least, district courts—and litigators—must carefully navigate holding expert witnesses to Rule 702's reliability standards while taking care not to frame arguments as contested fact issues.  This task is complicated by the panel majority's extensive criticism of the district court's detailed decision, which is at odds with the abuse-of-discretion standard governing appellate review of district court decisions under Rule 702.

In particular, a major factor in the majority's decision was the fact that Dr. Sahu “provided reasons” for using the data he did, ignoring other data, and other curious decisions in his analysis.  Most expert witnesses, especially those as experienced in the courtroom as Dr. Sahu, can contrive some explanation in response to criticism from an opposing party. It remains to be seen how a district court can evaluate these excuses without some assessment of the proffered evidence and the expert's credibility.

Litigators should keep the following principles in mind in opposing another party's expert witnesses:

• Frame the argument as far as possible in terms of methodology, comparing the expert witness's approach with established standards and methods outside the courtroom 
• Be cautious in how you attack the factual underpinnings of the expert witness's opinions.  Avoid detailed criticisms of individual sources that would invite the court to weigh evidence or make credibility determinations.
• You can sprinkle in other criticisms for atmospherics, but don't let it overwhelm your arguments grounded in Rule 702
• Think about these issues long before the time for expert challenges.  For example, when deposing an opposing expert witness, seek concessions about proper methodology in the relevant scientific field(s).  Try to box the expert in as to (a) what the expert actually did in the analysis in the case, and (b) the evidence the expert considered, ignored, or rejected and the reasons for each.

These suggestions are necessarily general and will need to be adapted to each jurisdiction's particular approach to Daubert challenges and the specific facts of each case.

What's next?

For now, the Fourth Circuit panel decision stands, and the case will return to the district court for further proceedings.  Defendants may be able to file another motion to exclude Dr. Sahu's opinions for reasons consistent with the Fourth Circuit's decision. A renewed expert challenge could be framed to avoid the panel's criticisms, focusing more narrowly on methodological flaws.  They may also urge summary judgment on a basis other than standing, including grounds they raised before that the district court did not reach.

Defendants, to be sure, can also petition the Supreme Court for certiorari. The high court may be intrigued by the standing issue, which raises an important issue of constitutional dimension affecting multiple jurisdictions. It is unlikely the Supreme Court would grant review with respect to the Daubert issue on its own and could decline to rule on that issue even if certiorari is granted.  Defendants have until February 2 to file a cert petition. 

Our team continues to monitor this case and related developments in jurisdictions across the United States. 

Authored by Lee Whitesell and Lacy G. Brown.