Skip to site navigation Skip to main content Skip to footer content Skip to Site Search page Skip to People Search page

Bylined Articles

Updated Federal Rules Can Improve Product Liability MDLs

By Alan Klein and William R. Heaston
June 11, 2024

Updated Federal Rules Can Improve Product Liability MDLs

By Alan Klein and William R. Heaston
June 11, 2024

Read below

In the evolving universe of multidistrict litigation, begun in the antitrust cases against major electronics manufacturers in the 1960s,[1] federal courts have developed varying approaches to fulfilling their responsibilities to achieve efficiency and reduce costs. This process continues today almost 60 years since the creation of the first MDL.

This article will highlight two recent federal rule changes that, in their implementation, hold great promise for plaintiffs and defendants alike by providing needed guidance in high-stakes consolidated litigation to achieve meaningful early discovery and the preparation of massed cases for trial, settlement, dismissal or remand.

The rule changes discussed are the amendment of Rule 702 of the Federal Rules of Evidence, relating to the admissibility of expert witness evidence, and proposed Rule 16.1 of the Federal Rules of Civil Procedure, which establishes a framework for early MDL case management. These changes create a pathway for a prioritized consideration and disposition of key issues, especially, but not exclusively, in product liability cases.

We will first consider amended Rule 702, which furnishes both trial judges and litigants with important guideposts in determining the admissibility of expert evidence. We then will highlight the features of proposed Rule 16.1, set to be approved and codified late next year, and analyze its promise and a few shortcomings.

At the conclusion of this article, we will share thoughts on how these rules can work together to create a framework for determining potentially dispositive issues involving plaintiff product use and general causation, which often take center stage in many MDLs involving prescription pharmaceuticals and medical devices, and in other product liability cases.

Why Rule 702 Was Amended

On Dec. 1, 2023, two changes to Rule 702 took effect.

First, the drafters added language clarifying that the proponent of expert testimony bears the burden of establishing that the testimony "more likely than not" meets the rule's reliability requirements. Second, the drafters revised Rule 702(d) to stress that an expert's opinion must reflect "a reliable application" of the expert's methodology.[2]

Notably, neither change was designed to introduce new standards regarding the admissibility of expert testimony; rather, the amendments merely sought to clarify how courts should have already been applying Rule 702.

And clarification was much needed. Over the past two decades, numerous courts have misconstrued and misapplied Rule 702, admitting the very sort of expert testimony that the rule was designed to exclude. Since 2000, the Judicial Conference Advisory Committee on the Federal Rules of Evidence's notes to Rule 702 have stressed — in accordance with the U.S. Supreme Court's 1993 ruling in Daubert v. Merrell Dow Pharmaceuticals Inc. and its progeny[3] — the "trial court's role as gatekeeper" and that "the proponent has the burden of establishing that the pertinent admissibility requirements are met by a preponderance of the evidence."[4]

Nonetheless, many courts have erroneously held that whether an expert has relied on what Rule 702 calls "sufficient facts or data," or reliably applied a given methodology, are questions of weight or credibility for the jury, rather than questions of admissibility for the judge. In so holding, courts have abdicated their gatekeeping role in favor of an overly lenient stance toward expert testimony, creating a presumption of admissibility that flips Rule 702 on its head.

These errors are apparent in many MDL cases. For one, judges presiding over MDLs have often failed to apply the preponderance of the evidence standard that Rule 702 demands.[5] For another, some judges in the MDL context have failed to assess whether experts reliably applied their chosen methodology, treating the issue as "a matter for cross-examination" instead.[6]

Although these errors are evident in non-MDL cases as well, the problems they generate are accentuated in the MDL context. Indeed, the MDL process principally exists to promote uniformity and efficiency; however, the unpredictability that stems from courts' inconsistent applications of Rule 702 undercuts both objectives. And because a given MDL typically involves hundreds if not thousands of cases, misapplications of Rule 702 can have far-reaching effects.

Given these considerations, the recent amendments to Rule 702 — and the clarity and consistency they aim to promote — are a particularly welcome addition to the MDL landscape.

Use of Rule 702 in MDLs: Meeting Daubert Gatekeeper Responsibilities and Advancing Case Dispositions

Against this backdrop of unpredictability and inconsistency, amended Rule 702 offers an opportunity for courts to embrace their role as gatekeepers. A number of judges presiding over recent MDLs have done just that.

Even before the amendments formally took effect in December, courts were already applying the guidelines articulated by the amended rule to determine the admissibility of expert testimony. For instance, in two antitrust MDLs, the district judges acknowledged the language of the then-proposed amendments to Rule 702 and took them into consideration in evaluating the admissibility of the expert opinions in question.[7]

On the product liability front, in 2022, the U.S. District Court for the Southern District of Florida in In re: Zantac (Ranitidine) Product Liability Litigation used Rule 702's gatekeeping principles to exclude expert testimony asserting that Zantac, a heartburn medication, causes cancer.[8] There, the court stressed that its gatekeeping role required it to "consider the reliability of the individual studies" used by the plaintiffs' experts, along with their "processes for evaluating and weighing the studies, to determine whether the studies reliably support the conclusions" that the experts reached.[9]

The Zantac court took its role seriously, finding that the experts' opinions exceeded the limitations of the studies they relied upon and therefore amounted to "overreaching conclusions."[10] Accordingly, the court granted summary judgment in favor of the defendants.[11] This is the very sort of close scrutiny of expert testimony that Rule 702 has always required — and that the amended rule intends.

Following the amendment of Rule 702, district courts in high-profile MDLs have relied upon it to closely scrutinize the reliability of expert opinions.[12]

For example, in April, the U.S. District Court for the Southern District of Illinois in In re: Paraquat Products Liability Litigation excluded the plaintiffs' sole expert on general causation and granted summary judgment in favor of the defendants.[13] There, the plaintiffs alleged that their exposure to paraquat, an herbicide, caused them to develop Parkinson's disease.[14]

After observing that Rule 702 was amended to ensure that judges properly exercised their gatekeeping responsibilities,[15] the court concluded that the plaintiffs' expert had failed to provide a reliable general causation opinion because the expert "inconsistently applied" his chosen methodology and even "at times transparently reverse-engineered" his analysis.[16]

As the court stated and as the amendments to Rule 702 make clear, "Rule 702 requires more than the label of a reliable methodology." That methodology must also be reliably applied.[17]

In the cases discussed above, the courts used the principles of the amended rule to exclude unreliable expert opinions. In so doing, they properly treated the factual basis of the experts' opinions and the application of their chosen methodologies as issues of admissibility for the judge, rather than matters of credibility for the jury.

In structuring their respective MDLs, these courts sequenced proceedings so the crucial issue of general causation would be addressed through early stage discovery and dispositive motions practice, thereby allowing the MDL judge to efficiently address and resolve that key issue.

Proposed FRCP 16.1: Streamlining MDLs Through Early Expert and Fact Discovery

Purpose and Current Status of Proposed Rule 16.1

In August 2023, the Judicial Conference Advisory Committee on Civil Rules published for comment a draft version of proposed Rule 16.1. The rule, as envisioned by its proponents, enhances early case assessment and management. Proposed Rule 16.1 recognizes the increasing importance and predominance of MDLs on federal dockets, which heavily weigh toward data breach, automobile, prescription pharmaceutical and medical device litigation.[18]

When circulated for public comment, the draft rule engendered considerable feedback from the judiciary, the bar, and legal groups representing both plaintiffs and defendants. The draft rule was revised by the advisory committee in April and recirculated; the committee estimates that by December 2025 the Supreme Court will consider and adopt proposed Rule 16.1, then transmit it to Congress.

What Proposed Rule 16.1 Provides

Proposed Rule 16.1 in its current form is similar in its purpose to its counterpart, Rule 16 of the Federal Rules of Civil Procedure; both address the court's initial pretrial conference. Proposed Rule 16.1, however, focuses solely on MDLs and addresses topics generally inapposite to other kinds of federal court litigation. These include the selection and appointment of leadership attorneys, the management of new cases coming into the MDL, the potential necessity for consolidated pleadings, and the coordination of proceedings in the MDL with other cases filed outside the MDL.

Unlike Rule 16, which requires a trial court to issue a scheduling order after receiving the parties' preconference report submitted under Rule 26(f), proposed Rule 16.1 adopts a precatory tone, using throughout such terms as "may" and "should," which has drawn negative comment from segments of the bar.

Others have supported such language because of the complexity of such cases in their claims and defenses, as well as the likelihood of additional cases filed directly in the MDL or transferred to the MDL by the Judicial Panel on Multidistrict Litigation, or JPML. Trial judges commenting upon the proposed draft rule have overwhelmingly supported its flexibility.

Implicit in the proposed rule is the realization, particularly in MDLs, that any initial case management order will not be the last word on the subject, as modifications and further orders will be essential as the case proceeds through preliminary motions, fact and expert discovery and, potentially, bellwether case selection and trials.

In addition to those aspects of MDL practice unique to the genre highlighted above, proposed Rule 16.1 provides a checklist of topics appropriate for consideration at the court's initial conference with the parties and counsel. These may be, and often are, memorialized in an initial pretrial order.

Matters that may be addressed at the initial conference, as enumerated in the proposed rule, are the identification of key factual and legal issues, when the parties will exchange information about their claims and defenses, a proposed discovery plan, a schedule for addressing pretrial motions, whether a magistrate or special master is necessary to address specific matters, and the scheduling of future pretrial conferences.

Features of Proposed Rule 16.1: Early Determinations of Expert Opinion Admissibility and Plaintiffs' Product Use

In the public comments received by the advisory committee, plaintiffs counsel voiced concern that a new civil rule was unnecessary and that MDL transferee courts were already implementing procedures equivalent to the existing Rule 16 relative to the initial pretrial case management conference. Others from the bar were concerned that the proposed rule was discretionary in its implementation; they also suggested additional topics for inclusion in an initial case management conference and order.

Defense counsel criticized the absence of provisions in the proposed rule to curtail meritless cases filed in the MDL or transferred into the MDL by the JPML.

While the draft rule released by the advisory committee in April did not completely assuage these concerns, the committee's notes sought to provide a gloss to their implementation to meet some of these criticisms.

Given the predominance of MDLs in the federal litigation landscape and their increasing importance, they provide a unique opportunity for courts and litigants to channel efforts and resources to achieve case milestones efficiently and effectively.

Early case management conferences, guided by proposed Rule 16.1 in its final form and following appointment of leadership attorneys, can set the stage for an early determination of key factual and legal issues.

This can be accomplished by the scheduling and resolution of Rule 12 motions, sequenced discovery beginning with early productions of relatively easily assembled documents and electronically stored information from both plaintiffs and defendants,[19] ascertaining the necessity for and utility of consolidated pleadings, and creating a plan for administering new case filings and tag-along transfers.

General Causation Resolution

In this context, if important scientific issues are at play in the MDL, the court and parties may need to consider the early exchange of information relating to general causation, namely whether the product or products involved in the case are capable of causing the injuries alleged by the plaintiffs. As the advisory committee found, general causation may be among the key issues "that should be addressed early in the proceeding."[20]

In certain high-profile MDLs discussed above, transferee courts created sequenced discovery and pretrial procedures to bring these issues to the fore following discovery and preliminary motions. As demonstrated in Zantac, and, most recently, in Paraquat, the MDL trial judges structured their MDLs to provide a framework and foundation for decisions on the important general causation issues in those cases that were central to the plaintiffs' claims.

Using amended Federal Rule of Evidence 702, these courts were able to address and resolve highly contested science issues relating to general causation prior to trial preparation and related proceedings.

Ascertaining Plaintiffs' Product Use

In most MDLs founded upon alleged injuries from products, one of the most important issues relates to the timing and extent of an individual plaintiff's use of or exposure to the product.

With cases transferred for MDL treatment by the JPML and others coming into the litigation via direct filing or other subsequent transfers, this information will be important for both the plaintiffs' counsel and their defense counterparts to determine throughout the consolidated proceedings. At the initial case management conference, therefore, and as provided for in proposed Rule 16.1, the parties, together or separately, may advise the transferee court of the need for discovery to achieve this objective.

In response to comments received from both plaintiffs counsel and the defense bar, the advisory committee highlighted this issue and suggested using fact sheets or a census mechanism for the early sharing of such information.[21] The use of such discovery can document key information such as the dates of each plaintiff's product use, exposure or ingestion; the nature of the alleged injury and its diagnosis date; medical treatment undertaken; the plaintiff's medical history; and any potential familial or other genetic confounders.

In endorsing the use of fact sheets and similar discovery devices in MDLs, the advisory committee found that "experience has shown that in many cases an early exchange of information about the factual bases for claims and defenses can facilitate efficient [case] management." The advisory committee also referenced attorney obligations under Rule 11(b) of the Federal Rules of Civil Procedure in support of its recommendation.[22]


[1] See, e.g., The University of Chicago School of Law, Legal Forum, Multidistrict Litigation and Choice of Law, at

[2] Fed. R. Evid. 702.

[3] See generally Daubert v. Merrell Dow Pharmaceuticals Inc. , 509 U.S. 579 (1993); General Electric Co. v. Joiner , 522 U.S. 136 (1997); Kumho Tire Co. v. Carmichael , 526 U.S. 137 (1999).

[4] Fed. R. Evid. 702 (2000 Amendments).

[5] See, e.g., In re: Zyprexa Products Liability Litigation , 489 F. Supp. 2d 230, 282 (E.D.N.Y. 2007) ("Since Rule 702 embodies a liberal standard of admissibility for expert opinions, the assumption the court starts with is that a well-qualified expert's testimony is admissible.") (quotation omitted); In re: Chantix (Varenicline) Prods. Liab. Litig. , 889 F. Supp. 2d 1272, 1297 (N.D. Ala. 2012) (citing authority indicating that "the factual basis of an expert opinion is assessed by the jury"); In re: Prempro Prods. Liab. Litig. , 2012 WL 13033298, at *3 (E.D. Ark. Apr. 11, 2012) ("[I]n most cases, objections to the inadequacies of a study are more appropriately considered an objection going to the weight of the evidence rather than its admissibility.") (quotation omitted).

[6] See, e.g., In re: Testosterone Replacement Therapy Prods. Liab. Litig. , 2017 WL 1833173, at *5 (N.D. Ill. May 8, 2017) ("The soundness of the factual underpinnings of the expert's analysis and the correctness of the expert's conclusions based on that analysis are factual matters to be determined by the jury.") (quotation omitted); In re: Lipitor (Atorvastatin Calcium) Mktg., Sales Practices & Prods. Liab. Litig. , 174 F. Supp. 3d 911, 921 (D.S.C. 2016) (finding that expert's alleged misapplication of Bradford Hill criteria was "a matter for cross-examination, not exclusion").

[7] See In re: Google Play Store Antitrust Litig. , 2023 WL 5532128, at *5 (N.D. Cal. Aug. 28, 2023) ("For present purposes, the Court is mindful of FRE 702 as it stands today and as it will be imminently amended."); In re: Payment Card Interchange Fee & Merchant Discount Antitrust Litig. , 2022 WL 15053250, at *4 n.9 (E.D.N.Y. Oct. 26, 2022) ("Because the amendments are not in force at the time this decision is published, the Court does not apply the amended version of Rule 702. However, in deciding these motions the Court is mindful of the proposed amendments' purpose ... .").

[8] In re: Zantac (Ranitidine) Prods. Liab. Litig. , 644 F. Supp. 3d 1075 (S.D. Fla. Dec. 6, 2022).

[9] Id. at 1168.

[10] Id. at 1216.

[11] See id. at 1277.

[12] In addition, the U.S. Court of Appeals for the Sixth Circuit in February affirmed the U.S. District Court for the Eastern District of Kentucky's grant of summary judgment after it excluded the plaintiffs' sole causation expert because his opinion that the defendants' drug caused heart failure was based upon unreliable studies and cherry-picked data. See In re: Onglyza (Saxagliptin) & Kombiglyze (Saxagliptin & Metformin) Prod. Liab. Litig. , 93 F. 4th 339, 345-47 (6th Cir. 2024). In so doing, the court noted that it "employ[ed] the old rule [702] because it was still in force at the time of the district court's decision," but in any event "the district court's reasoning align[ed] with the updated Rule 702." Id. at 345 n.4. Thus, the Sixth Circuit observed that its "decision here would be the same under either version of the rule." Id.

[13] 2024 WL 1659687 (S.D. Ill. Apr. 17, 2024) (excluding expert testimony); In re: Paraquat Prods. Liab. Litig. , 2024 WL 1655500 (S.D. Ill. Apr. 17, 2024) (granting summary judgment and dismissing four trial selected cases with prejudice, thereby leaving many cases pending for future disposition).

[14] Id. at *1.

[15] See id. at *4 nn. 8-9.

[16] Id. at 33.

[17] Id.

[18] Currently, over 60% of civil cases on federal dockets are in MDLs. Most of these are products liability actions: "Pending actions in products liability cases currently account for more than 90% of all actions pending across the MDL landscape." Bloomberg Law, 2023 Statistics Series: Multidistrict Litigation, found at

[19] Advisory Committee Notes (April 1, 2024) (hereinafter "Notes"), at Rule 16.1(b)(3)(B).

[20] Notes, id., at Rule 16.1(b)(3)(B).

[21] Id.

[22] Notes, id., at 16.1(b)(3)(B): "In some MDL proceedings, concerns have been raised on both the plaintiff side and the defense side that some claims and defenses have been asserted without the inquiry called for by Rule 11(b)…" Rule 11(b) requires that attorneys submitting every filing certify "that the factual contentions have evidentiary support or…will likely have evidentiary support after a reasonable opportunity for further investigation or discovery."

Reprinted with permission of Law360.