MDL defendants should insist that Rule 16.1, properly understood and applied, requires plaintiffs' firms to make early disclosures of basic verifying information about each of their cases. And defendants should further encourage courts to weed out baseless claims.
Executive Summary
Multidistrict litigation (MDL) proceedings were established almost a halfcentury ago to coordinate discovery and other pretrial matters when multiple cases involving overlapping factual issues are pending in different federal courts. But as the volume of MDL litigation has multiplied in recent years, some MDL courts facing hundreds, thousands, or even tens of thousands of cases have departed from ordinary application of the Federal Rules of Civil Procedure and managed cases on a largely ad hoc basis.
This proliferation of MDLs has become a serious problem. In particular, and as discussed in prior editions of ILR Briefly, the sprawling and undisciplined nature of many MDLs frequently diminishes defendants' ability to test the validity of individual cases and weed out meritless or unsupported claims.1 All too often, plaintiffs' firms cast a wide net to solicit clients so that they can stockpile an "inventory" of cases to maximize coercive settlement leverage regardless of the merits of the claims. And frequently, those firms do not adequately vet their clients or their claims.
In traditional, single-party litigation, the courts have procedural tools—such as motions to dismiss— that, while imperfect, can weed out meritless or unsupportable claims early in the case. But in the MDL context, many courts confronted with hundreds or thousands of consolidated lawsuits have effectively thrown up their hands, concluding that they lack the capacity to consider motions to dismiss each individual case. And plaintiffs' lawyers have convinced those courts that it is too burdensome for them to provide mandatory initial disclosures or basic discovery responses in each of the hundreds or thousands of cases they have filed. There is thus no mechanism to separate the weaker claims from the potentially meritorious and weed out the weaker or even entirely meritless claims.
"... [T]he sprawling and undisciplined nature of many MDLs frequently diminishes defendants' ability to test the validity of individual cases and weed out meritless or unsupported claims."
"Rule 16.1 reflects a meaningful step in the right direction in addressing abuses of the MDL process—in particular, the widespread filing of unverified or unsupportable claims that could not survive for long outside of the MDL context."
Against this backdrop, the federal Advisory Committee on Civil Rules formed an MDL Subcommittee in November 2017 to report on modern MDL practice and suggest possible amendments to the Federal Rules of Civil Procedure.2 The years-long efforts that followed culminated in the recent adoption of Federal Rule of Civil Procedure 16.1, which goes into effect on December 1, 2025.3 Rule 16.1 is the first rule of civil procedure to expressly address MDL proceedings, and it seeks to provide MDL courts with a framework for early case management and to develop a plan for "orderly pretrial activity in the MDL proceedings."4 Among other things, Rule 16.1(b)(3)(B) directs the parties to provide—in advance of the initial management conference— their views on "how and when the parties will exchange information about the factual bases for their claims and defenses."5 As the commentary to the Rule notes, lawyers' obligations under Rule 11 continue to apply in MDL proceedings, and Rule 16.1(b)(3)(B) is designed to ensure that claims are asserted in compliance with that Rule.6 Rule 16.1 further directs early judicial attention to "likely pretrial motions" and "the principal factual and legal issues likely to be presented."7
Rule 16.1 reflects a meaningful step in the right direction in addressing abuses of the MDL process—in particular, the widespread filing of unverified or unsupportable claims that could not survive for long outside of the MDL context. However, the Rule only establishes a process for raising these issues. Defendants have to use that process to urge MDL courts to require plaintiffs' counsel to provide basic verifying information about their claims at the outset—for example, that the claimant used the defendant's product at issue and suffered an injury—and to urge MDL courts to screen out unsupportable claims early in the proceedings.
How the Rule will operate in practice remains unknown. Plaintiffs' lawyers can be expected to continue to take advantage of the MDL process to try and coerce settlements based on claim inventory rather than merit, and to argue that Rule 16.1 does not require early scrutiny of each of their asserted claims. And some courts may decline to require early disclosures and to penalize plaintiffs' firms that file unverified or insupportable claims in violation of their professional obligations. Further reforms built on the initial foundation of Rule 16.1 would help curtail these likely abuses.
MDL Abuses and the Road to Rule 16.1
For the first few decades after the MDL statute was enacted in 1968, multidistrict litigation constituted only a small portion of federal civil litigation.8 It's an understatement to say that the volume of suits has changed dramatically. By 2018, over half of the overall civil caseload in federal courts was consolidated in MDLs.9 In recent years, the number of cases that are part of MDLs has only continued to swell.
As of January 2, 2025, there were 302,338 pending cases consolidated in active federal MDLs, with the vast majority involving personal injury claims.10 By comparison, there were 501,908 total civil cases pending in all U.S. district courts, of which 461,512 were private civil cases (not involving the federal government), according to the most recent available data published by the federal courts covering the period ending on December 31, 2024.11 Thus, MDLs account for nearly two thirds of the 2024 year-end total of all private civil litigation in federal court.
Especially given the prevalence of MDL proceedings in the landscape of federal civil litigation, it is critical that the Federal Rules of Civil Procedure—which are supposed to apply to all cases—govern in the MDL context. But the structure of MDLs includes built-in disadvantages for defendants that in practice deny defendants full use of many of those rules, including the rules related to motions to dismiss and discovery.12
The Problem of Unsupported Claims
Perhaps most significantly, it has been difficult for defendants in large mass tort MDLs to verify that all or even most of the cases filed against them are well grounded. In ordinary litigation, a defendant can file a motion to dismiss an insupportable lawsuit or seek early summary judgment based on initial discovery revealing that the plaintiff's claims are groundless. While this initial screening process is imperfect, it at least serves as a check on baseless lawsuits and is designed to reserve for potentially meritorious lawsuits the burdens of more intensive discovery and, if necessary, a trial.
In the world of mass tort MDLs, however, the number of claims asserted and the informational asymmetry between plaintiffs' counsel and defendants often mean that courts are unable to undertake a meaningful vetting process of individual cases.
A single district court confronted with hundreds, thousands, or tens of thousands of individual cases may conclude that it lacks the capacity to consider motions to dismiss individual cases, and plaintiffs' counsel often successfully resist producing initial discovery or basic verifying information in each of the hundreds or thousands of cases they have filed.13 Orders dismissing all or most of the cases in an MDL on the basis of broadly applicable issues like lack of jurisdiction, preemption, or the implausibility of the underlying allegations are rare, and in that unusual circumstance plaintiffs can take an immediate appeal. By contrast, defendants are generally unable to obtain interlocutory appellate review for decisions denying important dispositive motions.14
"A single district court confronted with hundreds, thousands, or tens of thousands of individual cases may conclude that it lacks the capacity to consider motions to dismiss individual cases, and plaintiffs' counsel often successfully resist producing initial discovery or basic verifying information in each of the hundreds or thousands of cases they have filed."
As a result, defendants in MDL proceedings often obtain at best selective application of key rules, including Rules 12(b)(6) (motions to dismiss), 12(e) (more definite statement), 26 (general discovery), 30 (depositions), 33 (interrogatories), 34 (document production), 36 (requests for admissions), and 56 (summary judgment).15 And without a mechanism to weed out weak claims from potentially meritorious ones, individual cases languish on the MDL docket until the MDL reaches a broader resolution—typically through global settlements or "inventory" settlements with the plaintiffs' firms that hold large groups of cases. For example, one study reported that between 2000 and 2015, 72 percent of MDL case terminations resulted from settlements.16 And, more broadly, it is exceedingly rare for cases to be remanded back to their originating court for trial. Since 1968, when Congress passed the MDL statute, transferee courts have remanded back to the originating courts fewer than three percent of all cases consolidated into an MDL, which means that transferee courts terminated over 97 percent of cases themselves.17
Plaintiffs' Lawyers Respond to the Incentive to Amass "Inventories" of Claims Without Regard to Merit
These dynamics—a lack of reliable vetting of individual cases combined with the pressure on defendants to settle on an inventory or global basis without the opportunity to assess which claims are baseless and which have potential merit—create a powerful incentive for plaintiffs' lawyers to generate the largest possible inventories of claims and file as many lawsuits as possible. That is exactly what happens. Plaintiffs' firms aggressively advertise and solicit clients and stockpile inventories of potential claimants—both to increase their settlement leverage and to jockey for lucrative positions as leadership counsel.
"Since 1968, when Congress passed the MDL statute, transferee courts have remanded back to the originating courts fewer than three percent of all cases consolidated into an MDL, which means that transferee courts terminated over 97 percent of cases themselves."
"These dynamics—a lack of reliable vetting of individual cases combined with the pressure on defendants to settle on an inventory or global basis without the opportunity to assess which claims are baseless and which have potential merit—create a powerful incentive for plaintiffs' lawyers to generate the largest possible inventories of claims and file as many lawsuits as possible. That is exactly what happens."
"... [A]s one court presiding over the Paraquat Products Liability MDL put it, cases presenting 'implausible or far-fetched theories of liability' and that 'would not have been filed but for the availability of ... multidistrict litigation' continue to populate the court's docket despite judicial efforts to clean up the docket."
Unfortunately, this all too often results in plaintiffs' firms filing dubious cases in the MDL mass tort context that would never be filed as standalone suits.18 As the MDL Subcommittee reported:
The unfortunate reality that confronts experienced lawyers in MDL proceedings is that a significant number of claimants in those proceedings turn out not to have supportable claims. Were there no MDL centralization, arguably, this would not be a problem. Defendants would have an opportunity to challenge individual claims one by one. Indeed, but for the MDL centralization order, many of those claims might not have reached court at all.19
The Subcommittee further estimated that typically 20 percent to 30 percent, and as many as 50 percent, of the claims included in mass tort MDL proceedings may be marginal or downright frivolous—for example, "because the claimant did not use the product involved, or because the claimant had not suffered the adverse consequence in suit, or because the pertinent statute of limitations had run before the claimant filed suit."20 For these reasons, as one court presiding over the Paraquat Products Liability MDL put it, cases presenting "implausible or far-fetched theories of liability" and that "would not have been filed but for the availability of this multidistrict litigation" continue to populate the court's docket despite judicial efforts to clean up the docket.21
There simply is no doubt that unsupported claims are rampant in mass tort MDLs.22 Plaintiffs' lawyers should be vetting their clients to ensure that they have a basis for presenting a claim and communicating with their clients throughout the process—steps that are mandated by Rule 11 and the American Bar Association's Model Rules of Professional Conduct.23 But experience suggests that these requirements often are not met in mass tort MDL proceedings.
Unsupported Claims Also Harm Legitimate Claimants
The harm imposed by the proliferation of baseless claims in MDL proceedings is not limited to defendants. Claimants who may have more legitimate claims are forced to wait for a global or inventory settlement rather than obtaining a prompt resolution of their claims on the merits, leading to further delays in the already overburdened court system.24 And when The harm imposed by the proliferation of baseless claims in MDL proceedings is not limited to defendants. Claimants who may have more legitimate claims are forced to wait for a global or inventory settlement rather than obtaining a prompt resolution of their claims on the merits, leading to further delays in the already overburdened court system.24 And when a legitimate plaintiff does recover under a settlement, his or her recovery is diluted by illegitimate claims that drain away resources that could instead be used to provide greater compensation to legitimate claimants. Simply put, the inventory-based rather than merit-based disposition of claims in many MDL proceedings results in legitimate claimants subsidizing claimants with weaker or even completely frivolous claims.
Because of this dynamic and the lack of attention to and vetting of the merits of individual claims in MDL proceedings, it is no surprise that MDL plaintiffs report widespread dissatisfaction with the MDL process. A study conducted by Professor Elizabeth Burch of the University of Georgia found that:
- More than 75 percent of MDL mass tort plaintiffs surveyed "did not know what was happening in their case while it was being litigated;"
- Nearly two thirds were "somewhat or extremely dissatisfied with their lawyers;" and
- More than 80 percent of those who settled "were somewhat or extremely dissatisfied with the fairness of the settlement process."25
In short, it seems that many claimants are treated as fungible inventory because there is no meaningful early vetting process that forces plaintiffs' counsel to communicate with their clients and analyze the facts of each individual case. Except for the illegitimate claimants and their lawyers, who obtain an undeserved windfall, the claims-warehousing approach to MDL proceedings harms everyone—defendants, legitimate claimants, and the judicial system alike.
"In short, it seems that many claimants are treated as fungible inventory because there is no meaningful early vetting process that forces plaintiffs' counsel to communicate with their clients and analyze the facts of each individual case."
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Originally published by U.S. Chamber of Commerce Institute for Legal Reform.
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