In Re: Hydrogen ( 2008 )


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  •                                                                                                                            Opinions of the United
    2008 Decisions                                                                                                             States Court of Appeals
    for the Third Circuit
    12-30-2008
    In Re: Hydrogen
    Precedential or Non-Precedential: Precedential
    Docket No. 07-1689
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    PRECEDENTIAL
    UNITED STATES COURT OF APPEALS
    FOR THE THIRD CIRCUIT
    No. 07-1689
    IN RE: HYDROGEN PEROXIDE
    ANTITRUST LITIGATION
    Arkema Inc., Arkema France S.A.,
    FMC Corp., Kemira Chemicals
    Canada, Inc., Kemira OYJ,
    Appellants
    On Appeal from the United States District Court
    for the Eastern District of Pennsylvania
    D.C. Civil Action No. 05-cv-0666
    and MDL No. 1682
    (Honorable Stewart Dalzell)
    Argued April 17, 2008
    Before: SCIRICA, Chief Judge,
    AMBRO and FISHER, Circuit Judges.
    (Filed December 30, 2008)
    STEVEN E. BIZAR, ESQUIRE (ARGUED)
    LANDON Y. JONES III, ESQUIRE
    THOMAS P. MANNING, ESQUIRE
    HOWARD D. SCHER, ESQUIRE
    Buchanan Ingersoll & Rooney
    1835 Market Street, 14th Floor
    Philadelphia, Pennsylvania 19103
    Attorneys for Appellants,
    Arkema Inc. and Arkema France SA
    MICHAEL I. FRANKEL, ESQUIRE
    Dechert LLP
    Cira Centre, 18th Floor
    2929 Arch Street
    Philadelphia, Pennsylvania 19104
    Attorney for Appellant,
    FMC Corporation
    JEFFREY S. CASHDAN, ESQUIRE
    STEPHEN P. CUMMINGS, ESQUIRE
    CHRISTINE A. HOPKINSON, ESQUIRE
    CATHERINE M. O’NEIL, ESQUIRE
    King & Spalding
    1180 Peachtree Street
    Atlanta, Georgia 30309
    2
    JOANNA J. CLINE, ESQUIRE
    BARBARA W. MATHER, ESQUIRE
    Pepper Hamilton
    3000 Two Logan Square
    18th & Arch Streets
    Philadelphia, Pennsylvania 19103
    Attorneys for Appellants,
    Kemira OYJ and Kemira Chemicals Canada, Inc.
    GREGORY K. ARENSON, ESQUIRE (ARGUED)
    ROBERT N. KAPLAN, ESQUIRE
    Kaplan Fox & Kilsheimer
    805 Third Avenue, 22nd Floor
    New York, New York 10022
    ANTHONY J. BOLOGNESE, ESQUIRE
    Bolognese & Associates
    Suite 320, Two Penn Center Plaza
    1500 John F. Kennedy Boulevard
    Philadelphia, Pennsylvania 19102
    WILLIAM P. BUTTERFIELD, ESQUIRE
    Cohen Milstein Hausfeld & Toll
    West Tower, Suite 500
    1100 New York Avenue, N.W.
    Washington, D.C. 20005
    Attorneys for Appellees,
    Artco Chemical, Inc., Astro Chemicals, Inc.,
    3
    Borden & Remington Corporation, Chem/Ser, Inc.,
    EMCO Chemical Distributors, Inc.,
    Finch Pruyn and Company, Inc.,
    Interstate Chemical Company, Lensco Products, Inc.,
    Lincoln Paper & Tissue, LLC, Ohio Chemical Services,
    Inc., James R. Pacific, Robert Chemical Company, Inc.,
    Safer Textile Processing Corporation, Young Chemical
    Company, City of Philadelphia, Borough of Middletown
    and Middletown Borough Authority
    STEVEN A. KANNER, ESQUIRE
    Freed Kanner London & Millen
    2201 Waukegan Road, Suite 130
    Bannockburn, Illinois 60015
    Attorney for Appellees,
    Direct Purchaser Plaintiffs and
    EMCO Chemical Distributors, Inc.
    OPINION OF THE COURT
    SCIRICA, Chief Judge.
    At issue in this antitrust action are the standards a district
    court applies when deciding whether to certify a class. We will
    vacate the order certifying the class in this case and remand for
    proceedings consistent with this opinion.
    4
    In deciding whether to certify a class under Fed. R. Civ.
    P. 23, the district court must make whatever factual and legal
    inquiries are necessary and must consider all relevant evidence
    and arguments presented by the parties. See Newton v. Merrill
    Lynch, Pierce, Fenner & Smith, Inc., 
    259 F.3d 154
    , 166, 167 (3d
    Cir. 2001) (citing Szabo v. Bridgeport Machs., Inc., 
    249 F.3d 672
    , 676 (7th Cir. 2001); Manual for Complex Litigation (Third)
    § 30.1 (1995)). In this appeal, we clarify three key aspects of
    class certification procedure. First, the decision to certify a class
    calls for findings by the court, not merely a “threshold showing”
    by a party, that each requirement of Rule 23 is met. Factual
    determinations supporting Rule 23 findings must be made by a
    preponderance of the evidence. Second, the court must resolve
    all factual or legal disputes relevant to class certification, even
    if they overlap with the merits—including disputes touching on
    elements of the cause of action. Third, the court’s obligation to
    consider all relevant evidence and arguments extends to expert
    testimony, whether offered by a party seeking class certification
    or by a party opposing it.
    I.
    Purchasers of hydrogen peroxide and related chemical
    products brought this antitrust conspiracy action against
    chemical manufacturers.1 An inorganic liquid, hydrogen
    1
    Named as defendants were Arkema, Inc., Arkema France
    S.A., FMC Corp., Degussa Corp., Degussa GmBH, Kemira
    Chemicals Canada, Inc., Kemira OYJ, Solvay America, Inc.,
    5
    peroxide is used most prominently as a bleach in the pulp and
    paper industry with smaller amounts appearing in chemicals and
    laundry products, environmental applications, textiles, and
    electronics. Hydrogen peroxide is available in solutions of
    different concentrations and grades depending on its intended
    use. Major concentrations are 35, 50, and 70 percent. The
    grades, roughly in order from least- to most-expensive, are:
    standard, food/cosmetic (which must meet FDA standards),
    electronic, and propulsion. All defendants sold the standard
    grade, but not all defendants sold all other grades. Defendants
    sold different amounts of each of the grades. Each grade has
    different supply and demand conditions because the grades are
    sold to end-users in a variety of industries with different
    economic characteristics. According to defendants, the different
    grades are not economic substitutes for each other, but plaintiffs
    disagree. Prices diverge dramatically among grades; electronic
    or propulsion grade can be as much as five times more
    Solvay Chemicals, Inc., Solvay S.A., EKA Chemicals, Inc.,
    Akzo Nobel, Inc., and Akzo Nobel Chemicals International B.V.
    Degussa Corp. and Degussa GmBH are now known as Evonik
    Degussa Corp. and Evonik Degussa GmBH, respectively. The
    following defendants are no longer participating in this appeal
    because plaintiffs voluntarily dismissed them after settlement:
    Evonik Degussa Corp., Evonik Degussa GmBH, EKA
    Chemicals, Inc., Akzo Nobel, Inc., Akzo Nobel Chemicals
    International B.V., Solvay S.A., Solvay America, Inc., and
    Solvay Chemicals, Inc.
    6
    expensive than standard grade.
    The other two products at issue are sodium percarbonate
    and sodium perborate, together known as persalts, which are
    granular solids containing hydrogen peroxide used primarily as
    detergents. Among the defendants, only Solvay produced and
    sold sodium percarbonate in the United States during the class
    period. Solvay Chemicals, Degussa Corp., and FMC sold
    sodium perborate in the United States during the class period.
    Akzo, Arkema, and Kemira did not sell or produce sodium
    perborate in the United States during the class period.
    After the United States Department of Justice and the
    European Commission began investigating possible violations
    of the antitrust laws in the hydrogen peroxide industry,2 several
    plaintiffs filed class action complaints against producers of
    hydrogen peroxide and persalts under § 4 of the Clayton Act, 15
    U.S.C. § 15, alleging a conspiracy in restraint of trade violating
    § 1 of the Sherman Act, 15 U.S.C. § 1. The Judicial Panel on
    2
    European Commission regulators charged eighteen
    hydrogen peroxide manufacturers with price-fixing on January
    31, 2005. In 2006, two defendants in this action, Solvay S.A.
    and Akzo Nobel Chemicals International, B.V., agreed to plead
    guilty in the United States to price-fixing in the hydrogen
    peroxide market for the period July 1, 1998 to December 1,
    2001. Solvay also agreed to plead guilty to price-fixing sodium
    perborate sold to one customer from June 1, 2000 to December
    1, 2001.
    7
    Multidistrict Litigation transferred all cognate federal actions to
    the United States District Court for the Eastern District of
    Pennsylvania, which consolidated the cases. See In re Hydrogen
    Peroxide Antitrust Litig., 
    374 F. Supp. 2d 1345
    (J.P.M.L. 2005).
    The consolidated amended complaint alleged that during an
    eleven-year class period (January 1, 1994–January 5, 2005)
    defendants (1) communicated about prices they would charge,
    (2) agreed to charge prices at certain levels, (3) exchanged
    information on prices and sales volume, (4) allocated markets
    and customers, (5) agreed to reduce production capacity, (6)
    monitored each other, and (7) sold hydrogen peroxide at agreed
    prices.
    The District Court denied defendants’ motion to dismiss
    the complaint for failure to state a claim. Following extensive
    discovery,3 plaintiffs moved to certify a class of direct
    purchasers of hydrogen peroxide, sodium perborate, and sodium
    percarbonate, over an eleven-year class period. In support of
    class certification, plaintiffs offered the opinion of an
    economist. Defendants, opposing class certification, offered the
    opinion of a different economist. Defendants separately moved
    to exclude the opinion of plaintiffs’ economist as unreliable
    under Daubert v. Merrell Dow Pharmaceuticals, Inc., 
    509 U.S. 3
        Defendants assert, and plaintiffs do not dispute, that they
    provided to plaintiffs all available sales transactions and other
    market data relevant to how hydrogen peroxide and persalts
    were bought and sold during the class period.
    8
    579 (1993). Concluding plaintiffs’ expert’s opinion was
    admissible and supported plaintiffs’ motion for class
    certification, the District Court certified a class of direct
    purchasers of hydrogen peroxide, sodium perborate, and sodium
    percarbonate under Fed. R. Civ. P. 23(b)(3). See In re
    Hydrogen Peroxide Antitrust Litig., 
    240 F.R.D. 163
    (E.D. Pa.
    2007). The District Court identified seven issues to be tried on
    a class-wide basis: (1) whether defendants and others engaged
    in a combination and conspiracy to fix, raise, maintain, or
    stabilize prices; allocate customers and markets; or control and
    restrict output of hydrogen peroxide, sodium perborate, and
    sodium percarbonate sold in the United States; (2) the identity
    of the participants in the alleged conspiracy; (3) the duration of
    the alleged conspiracy and the nature and character of
    defendants’ acts performed in furtherance of it; (4) the effect of
    the alleged conspiracy on the prices of hydrogen peroxide and
    persalts during the class period; (5) whether the alleged
    conspiracy violated the Sherman Act; (6) whether the activities
    alleged in furtherance of the conspiracy or their effect on the
    prices of hydrogen peroxide and persalts during the class period
    injured named plaintiffs and the other members of the class; and
    (7) the proper means of calculating and distributing damages.
    The class was defined as:
    All persons or entities, including state, local and
    municipal government entities (but excluding
    defendants, their parents, predecessors,
    successors, subsidiaries, and affiliates as well as
    9
    federal government entities) who purchased
    hydrogen peroxide, sodium perborate, or sodium
    percarbonate in the United States, its territories, or
    possessions, or from a facility located in the
    United States, its territories, or possessions,
    directly from any of the defendants, or from any
    of their parents, predecessors, successors,
    subsidiaries, or affiliates, at any time during the
    period from September 14, 1994 to January 5,
    2005.
    We granted defendants’ petition for an interlocutory
    appeal under Fed. R. Civ. P. 23(f).4
    II.
    Class certification is proper only “if the trial court is
    satisfied, after a rigorous analysis, that the prerequisites” of Rule
    23 are met.5 Gen. Tel. Co. of Sw. v. Falcon, 
    457 U.S. 147
    , 161
    4
    The District Court had jurisdiction under 28 U.S.C. §§ 1331,
    1337. We have jurisdiction under 28 U.S.C. § 1292(e) and Fed.
    R. Civ. P. 23(f).
    5
    Although the Supreme Court in the quoted statement
    addressed Fed. R. Civ. P. 23(a), there is “no reason to doubt”
    that the language “applies with equal force to all Rule 23
    requirements, including those set forth in Rule 23(b)(3).” In re
    Initial Pub. Offerings Sec. Litig., 
    471 F.3d 24
    , 33 n.3 (2d Cir.
    10
    (1982); see Beck v. Maximus, Inc., 
    457 F.3d 291
    , 297 (3d Cir.
    2006); see also Amchem Prods., Inc. v. Windsor, 
    521 U.S. 591
    ,
    615 (1997) (Rule 23(b)(3) requirements demand a “close look”).
    “A class certification decision requires a thorough examination
    of the factual and legal allegations.” 
    Newton, 259 F.3d at 166
    .6
    2006).
    6
    A class action is
    an exception to the usual rule that litigation is
    conducted by and on behalf of the individual
    named parties only. Class relief is peculiarly
    appropriate when the issues involved are common
    to the class as a whole and when they turn on
    questions of law applicable in the same manner to
    each member of the class. For in such cases, the
    class-action device saves the resources of both the
    courts and the parties by permitting an issue
    potentially affecting every [class member] to be
    litigated in an economical fashion under Rule 23.
    
    Falcon, 457 U.S. at 155
    (quotation marks and citations omitted)
    (alteration in original) (quoting Califano v. Yamasaki, 
    442 U.S. 682
    , 700–01 (1979)).
    Class certification under Rule 23 has two primary
    components. The party seeking class certification must first
    establish the four requirements of Rule 23(a): “(1) the class is so
    numerous that joinder of all members is impracticable
    [numerosity]; (2) there are questions of law or fact common to
    11
    The trial court, well-positioned to decide which facts and
    legal arguments are most important to each Rule 23 requirement,
    possesses broad discretion to control proceedings and frame
    issues for consideration under Rule 23. See 
    Amchem, 521 U.S. at 630
    (Breyer, J., concurring in part and dissenting in part)
    (recognizing that the decision on class certification may
    implicate “highly fact-based, complex, and difficult matters”).
    But proper discretion does not soften the rule: a class may not be
    certified without a finding that each Rule 23 requirement is met.
    Careful application of Rule 23 accords with the pivotal status of
    class certification in large-scale litigation, because
    denying or granting class certification is often the
    defining moment in class actions (for it may
    sound the “death knell” of the litigation on the
    part of plaintiffs, or create unwarranted pressure
    the class [commonality]; (3) the claims or defenses of the
    representative parties are typical of the claims or defenses of the
    class [typicality]; and (4) the representative parties will fairly
    and adequately protect the interests of the class [adequacy].”
    Fed. R. Civ. P. 23(a). If all four requirements of Rule 23(a) are
    met, a class of one of three types (each with additional
    requirements) may be certified.           See Fed. R. Civ. P.
    23(b)(1)–(3). (Rule 23 received stylistic revisions effective
    December 1, 2007. Fed. R. Civ. P. 23 advisory committee’s
    note, 2007 Amendment. We quote the restyled version; its
    changes are immaterial to this appeal.)
    12
    to settle nonmeritorious claims on the part of
    defendants) . . . .
    
    Newton, 259 F.3d at 162
    ; see 
    id. at 167
    (“Irrespective of the
    merits, certification decisions may have a decisive effect on
    litigation.”); see also Coopers & Lybrand v. Livesay, 
    437 U.S. 463
    , 476 (1978). In some cases, class certification “may force
    a defendant to settle rather than incur the costs of defending a
    class action and run the risk of potentially ruinous liability.”
    Fed. R. Civ. P. 23 advisory committee’s note, 1998
    Amendments. Accordingly, the potential for unwarranted
    settlement pressure “is a factor we weigh in our certification
    calculus.” 
    Newton, 259 F.3d at 168
    n.8. The Supreme Court
    recently cautioned that certain antitrust class actions may present
    prime opportunities for plaintiffs to exert pressure upon
    defendants to settle weak claims. See Bell Atl. Corp. v.
    Twombly, 
    127 S. Ct. 1955
    , 1967 (2007).
    III.
    Here, the District Court found the Rule 23(a)
    requirements were met, a determination defendants do not now
    challenge. Plaintiffs sought certification under Rule 23(b)(3),
    which is permissible when the court “finds that the questions of
    law or fact common to class members predominate over any
    questions affecting only individual members, and that a class
    action is superior to other available methods for fairly and
    13
    efficiently adjudicating the controversy.” 7 Fed. R. Civ. P.
    23(b)(3). The twin requirements of Rule 23(b)(3) are known as
    predominance and superiority.
    Only the predominance requirement is disputed in this
    appeal. Predominance “tests whether proposed classes are
    sufficiently cohesive to warrant adjudication by representation,”
    
    Amchem, 521 U.S. at 623
    , a standard “far more demanding”
    than the commonality requirement of Rule 23(a), 
    id. at 623–24,
    “requiring more than a common claim,” 
    Newton, 259 F.3d at 187
    . “Issues common to the class must predominate over
    individual issues . . . .” In re The Prudential Ins. Co. of Am.
    7
    See Fed. R. Civ. P. 23(b)(3) advisory committee’s note,
    1966 Amendment (“The court is required to find, as a condition
    of holding that a class action may be maintained under this
    subdivision, that the questions common to the class predominate
    over the questions affecting individual members. It is only
    where this predominance exists that economies can be achieved
    by means of the class-action device.”).
    Rule 23(b)(3) identifies some “matters pertinent to these
    findings”: “(A) the class members’ interests in individually
    controlling the prosecution or defense of separate actions; (B)
    the extent and nature of any litigation concerning the
    controversy already begun by or against class members; (C) the
    desirability or undesirability of concentrating the litigation of the
    claims in the particular forum; and (D) the likely difficulties in
    managing a class action.” Fed. R. Civ. P. 23(b)(3)(A)–(D).
    14
    Sales Practices Litig., 
    148 F.3d 283
    , 313–14 (3d Cir. 1998).
    Because the “nature of the evidence that will suffice to resolve
    a question determines whether the question is common or
    individual,” Blades v. Monsanto Co., 
    400 F.3d 562
    , 566 (8th
    Cir. 2005), “‘a district court must formulate some prediction as
    to how specific issues will play out in order to determine
    whether common or individual issues predominate in a given
    case,’” In re New Motor Vehicles Can. Exp. Antitrust Litig., 
    522 F.3d 6
    , 20 (1st Cir. 2008) [hereinafter New Motor Vehicles]
    (quoting Waste Mgmt. Holdings, Inc. v. Mowbray, 
    208 F.3d 288
    ,
    298 (1st Cir. 2000)).8 “If proof of the essential elements of the
    cause of action requires individual treatment, then class
    certification is unsuitable.”      
    Newton, 259 F.3d at 172
    .
    Accordingly, we examine the elements of plaintiffs’ claim
    “through the prism” of Rule 23 to determine whether the District
    Court properly certified the class. 
    Id. at 181.
    A.
    The elements of plaintiffs’ claim are (1) a violation of the
    antitrust laws—here, § 1 of the Sherman Act, (2) individual
    injury resulting from that violation, and (3) measurable
    damages. 15 U.S.C. § 15; Am. Bearing Co. v. Litton Indus., Inc.,
    
    729 F.2d 943
    , 948 (3d Cir. 1984); 
    Blades, 400 F.3d at 566
    .
    8
    See Sandwich Chef, Inc. v. Reliance Nat’l Indem. Ins. Co.,
    
    319 F.3d 205
    , 218 (5th Cir. 2003) (Rule 23(b)(3) requires the
    court to “consider how a trial on the merits would be conducted
    if a class were certified”).
    15
    Importantly, individual injury (also known as antitrust impact)
    is an element of the cause of action; to prevail on the merits,
    every class member must prove at least some antitrust impact
    resulting from the alleged violation. Bogosian v. Gulf Oil Corp.,
    
    561 F.2d 434
    , 454 (3d Cir. 1977); see 
    Newton, 259 F.3d at 188
    (In antitrust and securities fraud class actions, “[p]roof of injury
    (whether or not an injury occurred at all) must be distinguished
    from calculation of damages (which determines the actual value
    of the injury)”).
    In antitrust cases, impact often is critically important for
    the purpose of evaluating Rule 23(b)(3)’s predominance
    requirement because it is an element of the claim that may call
    for individual, as opposed to common, proof. See New Motor
    
    Vehicles, 522 F.3d at 20
    (“In antitrust class actions, common
    issues do not predominate if the fact of antitrust violation and
    the fact of antitrust impact cannot be established through
    common proof.”); Bell Atl. Corp. v. AT&T Corp., 
    339 F.3d 294
    ,
    302 (5th Cir. 2003) (“[W]here fact of damage cannot be
    established for every class member through proof common to
    the class, the need to establish antitrust liability for individual
    class members defeats Rule 23(b)(3) predominance.”); see also
    
    Blades, 400 F.3d at 572
    (“[P]roof of conspiracy is not proof of
    common injury.”).
    Plaintiffs’ burden at the class certification stage is not to
    prove the element of antitrust impact, although in order to
    prevail on the merits each class member must do so. Instead, the
    task for plaintiffs at class certification is to demonstrate that the
    16
    element of antitrust impact is capable of proof at trial through
    evidence that is common to the class rather than individual to its
    members. Deciding this issue calls for the district court’s
    rigorous assessment of the available evidence and the method or
    methods by which plaintiffs propose to use the evidence to
    prove impact at trial. See Fed. R. Civ. P. 23 advisory
    committee’s note, 2003 Amendments (“A critical need is to
    determine how the case will be tried.”); see, e.g., In re
    Linerboard Antitrust Litig., 
    305 F.3d 145
    , 155 (3d Cir. 2002)
    (“reject[ing] the contention that plaintiffs did not demonstrate
    that sufficient proof was available, for use at trial, to prove
    antitrust impact common to all the members of the class”).
    Here, the District Court found the predominance
    requirement was met because plaintiffs would be able to use
    common, as opposed to individualized, evidence to prove
    antitrust impact at trial. On appeal, defendants contend the
    District Court erred in three principal respects in finding
    plaintiffs satisfied the predominance requirement: (1) by
    applying too lenient a standard of proof for class certification,
    (2) by failing meaningfully to consider the views of defendants’
    expert while crediting plaintiffs’ expert, and (3) by erroneously
    applying presumption of antitrust impact under 
    Bogosian, 561 F.2d at 454
    –55.
    We review a class certification order for abuse of
    discretion, which occurs if the district court’s decision “rests
    upon a clearly erroneous finding of fact, an errant conclusion of
    law or an improper application of law to fact.” Newton, 
    259 17 F.3d at 165
    . “[W]hether an incorrect legal standard has been
    used is an issue of law to be reviewed de novo.” In re Initial
    Pub. Offerings Sec. Litig., 
    471 F.3d 24
    , 32 (2d Cir. 2006)
    [hereinafter IPO] (citation omitted).9
    B.
    We summarize briefly the evidence and arguments
    offered to the District Court. As noted, both plaintiffs and
    defendants presented the opinions of expert economists.
    Importantly, the experts disagreed on the key disputed
    predominance issue—whether antitrust impact was capable of
    proof at trial through evidence common to the class, as opposed
    to individualized evidence.
    Plaintiffs’ expert, John C. Beyer, Ph.D., offered an
    opinion purporting to show that “there is common proof that can
    9
    See Koon v. United States, 
    518 U.S. 81
    , 100 (1996) (“A
    district court by definition abuses its discretion when it makes
    an error of law.”); Regents of Univ. of Cal. v. Credit Suisse First
    Boston (USA), Inc., 
    482 F.3d 372
    , 380 (5th Cir. 2007)
    (“Whether the district court applied the correct legal standard in
    reaching its decision on class certification . . . is a legal question
    that we review de novo.” (quoting Allison v. Citgo Petroleum
    Corp., 
    151 F.3d 402
    , 408 (5th Cir. 1998)) (quotation marks
    omitted); Elcock v. Kmart Corp., 
    233 F.3d 734
    , 745 (3d Cir.
    2000) (“Because we are evaluating the District Court’s legal
    interpretation of a federal rule, our review is plenary.”).
    18
    be used to demonstrate that the alleged conspiracy to raise
    prices, restrict output and allocate customers would have
    impacted all purchasers of hydrogen peroxide, sodium
    perborate, and sodium percarbonate.” Beyer’s “market analysis”
    suggested that conditions in the hydrogen peroxide industry
    favored a conspiracy that would have impacted the entire class.
    First, hydrogen peroxide and persalts are fungible,
    undifferentiated commodity products, which means producers
    compete on price, not quality or other features. Second,
    production is heavily concentrated in a small group of
    manufacturers.10 Third, there are high barriers to entry in the
    industry and no close economic substitutes, preventing any
    competitors from entering the market and undercutting prices.
    Fourth, defendants’ geographic markets overlapped, so that
    purchasers would have benefitted from price competition if not
    for the alleged conspiracy.
    Beyer also observed a “pricing structure” in the hydrogen
    peroxide industry which, he contended, showed prices across
    producers, grades and concentrations of hydrogen peroxide, and
    10
    As defendants note, however, DuPont—not a named
    defendant—was a major producer of hydrogen peroxide (with
    about 25 percent market share) during the beginning of the class
    period until it left the market in 1999.
    19
    end uses moved similarly over time. 11 This, according to Beyer,
    suggested a conspiracy would have impacted all class members:
    My analysis of the similarity in price movements
    over time indicates that hydrogen peroxide prices
    charged by different manufacturers are affected
    by the same market forces of supply and demand
    . . . . These similarities in movement are
    sometimes referred to as “pricing structure” or
    “structure to prices.” This analysis confirms that
    prices would have behaved similarly, in a
    consistent and generalized manner[,] to a
    conspiracy to fix prices at artificially high levels
    [and] to restrict output or to allocate customers.
    Beyer also pointed to coordinated increases in list prices by
    defendants as evidence of common impact.
    Beyer identified two “potential approaches” to estimating
    damages on a class-wide basis: (1) benchmark analysis, which
    would compare actual prices during the alleged conspiracy with
    prices that existed before the class period; and (2) regression
    analysis, through which it “may be possible . . . to estimate the
    relationship between price of hydrogen peroxide, sodium
    perborate, and sodium percarbonate and the various market
    forces that influence prices, including demand and supply
    11
    Beyer also contended sodium perborate sales exhibited a
    pricing structure over the “long-term trend.”
    20
    variables.” These methods, according to Beyer, could be used
    to estimate the prices plaintiffs would have faced but for the
    conspiracy. Beyer stated that “sufficient reliable data” exist to
    allow him to employ one or both of the potential approaches.
    Defendants offered the opinion of their own expert
    economist, Janusz A. Ordover, Ph.D., to “provide an
    independent expert assessment of whether certification of the
    proposed class of Plaintiffs is appropriate in this matter.”
    Specifically, Ordover set out to address “whether, assuming a
    conspiracy of the kind described in the Complaint, the Plaintiffs
    will be able to show, through common proof, that all or virtually
    all of the members of the proposed class suffered economic
    injury caused by the alleged conspiracy.” Ordover also
    “opine[d] on whether a formulaic approach exists by which
    impact could be demonstrated and damages to the class could be
    reasonably calculated.” Ordover responded to and disputed
    many of Beyer’s opinions.
    First, Ordover disputed Beyer’s finding that hydrogen
    peroxide and persalts are fungible, contending that the “various
    grades of hydrogen peroxide . . . [and persalts] have different
    supply characteristics and face different demand conditions.
    The existence of supply and demand characteristics that are
    specific to the various grades and uses requires individualized
    assessment of the impact of the alleged conspiracy at least
    across these different grades and uses. Consequently, a finding
    of class-wide impact from the alleged conspiracy cannot be
    inferred from the mere fact of the conspiracy and from common
    21
    evidence.” Second, Ordover alleged that, over the eleven-year
    proposed class period, “the industry experienced prolonged
    periods of increasing capacity, increasing production, and an
    overall trend of declining real and nominal prices in the face of
    stable or increasing costs.” Ordover disputed Beyer’s pricing
    structure analysis, contending “there is no tendency for prices
    charged to individual customers to move together, which
    indicates that the alleged conspiracy cannot be shown to have
    had class-wide impact,” necessitating individualized inquiries to
    determine whether a customer incurred impact.
    Ordover also found some of defendants’ price-increase
    announcements were ineffective—actual prices did not follow
    the purported announcements—suggesting list prices could not
    be used to measure antitrust impact on a basis common to the
    class. Ordover observed that a number of contracts for the sale
    of hydrogen peroxide were individually negotiated, with a
    variety of contract terms. And deposition testimony from named
    plaintiffs indicated list prices were sometimes disregarded.
    Ordover opined that the statistical methods by which Beyer
    proposed to demonstrate common impact and damages were not
    feasible. Given the record of prices and output in the industry
    and the apparent influence of individualized factors on pricing,
    “class-wide assessment of impact based on aggregate price
    information [was] impossible,” and any formulaic approach to
    determine a set of “but-for prices” would have to incorporate a
    multitude of different “variables,” defeating any reasonable
    notion of proof common to the class.
    22
    Significantly, Ordover presented empirical analysis of the
    data on individual sales transactions and found that different
    customers purchasing the two most common grades and three
    most common concentrations from the same hydrogen peroxide
    producer in a given year were as likely to experience a decline
    in actual prices over the year as an increase, while other
    similarly situated customers experienced no change in price.
    Defendants contend this disparity goes to the core of the
    predominance issue—plaintiffs and their expert, Beyer, failed to
    “explain . . . how or which common proof could be used to
    determine that the alleged conspiracy impacted customers whose
    prices declined, as well as customers whose prices increased or
    stayed the same, over the same time period.” 12 Br. of Appellant
    at 5. Beyer, according to defendants, only “promised” to come
    up with a method to overcome this obstacle, without showing or
    even suggesting how it might be done. Defendants contend the
    market analysis is “generic” and note it would apply equally to
    a large number of industries. With respect to the pricing
    structure analysis, they contend Beyer’s use of average prices,
    rather than those of individual transactions, to show pricing
    structure, was erroneous because it glossed over differences in
    actual prices. The theme of defendants’ argument is that the
    12
    See ABA Section of Antitrust Law, Econometrics 210
    (2005) (“Generally, when the prices for some customers are
    going up while the prices of other customers are not, there is
    reason to doubt that the different customers (class members) are
    experiencing a common impact.”).
    23
    data, which Ordover analyzed, rebut Beyer’s “theory” that
    common proof was feasible. Beyer’s and Ordover’s analyses
    are irreconcilable.
    In addition to presenting Ordover’s testimony, defendants
    moved to exclude Beyer’s testimony as unreliable, citing
    Daubert v. Merrell Dow Pharmaceuticals, Inc., 
    509 U.S. 579
    (1993).13 The District Court denied the Daubert motion in its
    memorandum and order certifying the class.
    C.
    The District Court concluded the predominance
    requirement was met. It held that “[e]ither [Beyer’s] market
    13
    Before the District Court, both parties agreed Fed. R. Evid.
    702 and Daubert should be applied to assess whether Beyer’s
    testimony should be admitted for consideration. On appeal,
    neither party argues otherwise, and defendants do not now
    challenge the District Court’s denial of the Daubert motion.
    (The District Court stated that “because the evidence is here
    offered for the limited purpose of class certification, our inquiry
    is perhaps less exacting than it might be for evidence to be
    presented at trial.”) As we explain, however, a district court’s
    conclusion that an expert’s opinion is admissible does not
    necessarily dispose of the ultimate question—whether the
    district court is satisfied, by all the evidence and arguments
    including all relevant expert opinion, that the requirements of
    Rule 23 have been met.
    24
    analysis or the pricing structure analysis would likely be
    independently sufficient at this stage. Plaintiffs and Dr. Beyer
    have provided us with both. Despite defendants’ claims to the
    contrary, we should require no more of plaintiffs in a motion for
    class certification.” Because hydrogen peroxide is fungible, the
    court found, “purchasing decisions [are] made primarily on the
    basis of price rather than quality or specific properties,” and
    “price is by far the most significant means of competition among
    producers and an agreement to control prices will seriously
    hinder competition.” The court rejected defendants’ objection
    that different grades and concentrations of hydrogen peroxide
    called into question its fungibility. The prices of the grades and
    concentrations were related to each other, so in the view of the
    court, the differences would not preclude common proof of
    antitrust impact. Defendants’ high combined market share
    meant that “no competitor who was not a member of the
    conspiracy would be able to take up the slack and keep prices
    stable.” The high barriers to entry and lack of economic
    substitutes implied “a conspiracy such as the one alleged here
    [could] continue indefinitely with limited risk that a new
    competitor would enter the market and undercut the agreed-
    upon prices.” Also, the court accepted Beyer’s opinion that
    “prices in the hydrogen peroxide industry moved similarly over
    time and the industry exhibited structure in pricing.” The court
    added that it believed “plaintiffs would be able to show antitrust
    impact on all purchasers merely by showing that defendants kept
    list prices that were artificially high because of their
    conspiracy.”
    25
    The District Court held that it was sufficient that Beyer
    proposed reliable methods for proving impact and damages; it
    did not matter that Beyer had not completed any benchmark or
    regression analyses, and the court would not require plaintiffs to
    show at the certification stage that either method would work.
    IV.
    A.
    Defendants contend the District Court applied too lenient
    a standard of proof with respect to the Rule 23 requirements by
    (1) accepting only a “threshold showing” by plaintiffs rather
    than making its own determination, (2) requiring only that
    plaintiffs demonstrate their “intention” to prove impact on a
    class-wide basis, and (3) singling out antitrust actions as
    appropriate for class treatment even when compliance with Rule
    23 is “in doubt.”
    Although it is clear that the party seeking certification
    must convince the district court that the requirements of Rule 23
    are met, little guidance is available on the subject of the proper
    standard of “proof” for class certification.14 The Supreme Court
    has described the inquiry as a “rigorous analysis,” 
    Falcon, 457 U.S. at 161
    , and a “close look,” 
    Amchem, 521 U.S. at 615
    , but
    14
    The burden of proof rests on the movant. See Unger v.
    Amedisys Inc., 
    401 F.3d 316
    , 320 (5th Cir. 2005) (“The party
    seeking certification bears the burden of establishing that all
    requirements of Rule 23 have been satisfied.”).
    26
    it has elaborated no further.
    1.
    The following principles guide a district court’s class
    certification analysis. First, the requirements set out in Rule 23
    are not mere pleading rules. 
    Szabo, 249 F.3d at 675
    –77. The
    court may “‘delve beyond the pleadings to determine whether
    the requirements for class certification are satisfied.’” 
    Newton, 259 F.3d at 167
    (quoting 5 James Wm. Moore et al., Moore’s
    Federal Practice § 23.61[5]); see 
    Beck, 457 F.3d at 297
    (same);
    see also Johnston v. HBO Film Mgmt., Inc., 
    265 F.3d 178
    , 189
    (3d Cir. 2001) (district court properly “examine[d] the factual
    record underlying plaintiffs’ allegations in making its
    certification decision”).15
    15
    See 5 James Wm. Moore et al., Moore’s Federal Practice
    § 23.61[1] (3d ed. 2008) (“Pleading requirements are distinct
    from the requirements for certifying a case as a class action. A
    court may not and should not certify a class action without a
    rigorous examination of the facts to determine if the certification
    requirements of Rule 23(a) and (b) have been met.” (citation
    omitted)); 
    Szabo, 249 F.3d at 675
    (“The proposition that a
    district judge must accept all of the complaint’s allegations
    when deciding whether to certify a class cannot be found in Rule
    23 and has nothing to recommend it.”); see also 
    Unger, 401 F.3d at 321
    ) (“The plain text of Rule 23 requires the court to
    ‘find,’ not merely assume, the facts favoring class certification.”
    (quoting Fed. R. Civ. P. 23(b)(3))); Gariety v. Grant Thornton,
    27
    LLP, 
    368 F.3d 356
    , 365 (4th Cir. 2004) (“If it were appropriate
    for a court simply to accept the allegations of a complaint at face
    value in making class action findings, every complaint asserting
    the requirements of Rule 23(a) and (b) would automatically lead
    to a certification order, frustrating the district court’s
    responsibilities for taking a ‘close look’ at relevant matters, for
    conducting a ‘rigorous analysis’ of such matters, and for making
    ‘findings’ that the requirements of Rule 23 have been satisfied.”
    (citations omitted)); Tardiff v. Knox County, 
    365 F.3d 1
    , 4–5
    (1st Cir. 2004) (“It is sometimes taken for granted that the
    complaint’s allegations are necessarily controlling; but class
    action machinery is expensive and in our view a court has the
    power to test disputed premises early on if and when the class
    action would be proper on one premise but not another.”). In
    Szabo, the Court of Appeals for the Seventh Circuit offered this
    persuasive explanation:
    The reason why judges accept a complaint’s
    factual allegations when ruling on motions to
    dismiss under Rule 12(b)(6) is that a motion to
    dismiss tests the legal sufficiency of a pleading.
    Its factual sufficiency will be tested later—by a
    motion for summary judgment under Rule 56, and
    if necessary by trial. By contrast, an order
    certifying a class usually is the district judge’s last
    word on the subject; there is no later test of the
    decision’s factual premises (and, if the case is
    28
    An overlap between a class certification requirement and
    the merits of a claim is no reason to decline to resolve relevant
    disputes when necessary to determine whether a class
    certification requirement is met. Some uncertainty ensued when
    the Supreme Court declared in Eisen v. Carlisle & Jacquelin,
    
    417 U.S. 156
    , 177 (1974), that there is “nothing in either the
    language or history of Rule 23 that gives a court any authority
    to conduct a preliminary inquiry into the merits of a suit in order
    to determine whether it may be maintained as a class action.”
    Only a few years later, in addressing whether a party may bring
    an interlocutory appeal when a district court denies class
    certification,16 the Supreme Court pointed out that “the class
    determination generally involves considerations that are
    ‘enmeshed in the factual and legal issues comprising the
    plaintiff’s cause of action.’” 
    Livesay, 437 U.S. at 469
    (quoting
    Mercantile Nat’l Bank v. Langdeau, 
    371 U.S. 555
    , 558 (1963)).
    As we explained in 
    Newton, 259 F.3d at 166
    –69, Eisen is best
    understood to preclude only a merits inquiry that is not
    necessary to determine a Rule 23 requirement. Other courts of
    settled, there could not be such an examination
    even if the district judge viewed the certification
    as 
    provisional). 249 F.3d at 675
    –76.
    16
    This case pre-dated Fed. R. Civ. P. 23(f), which provides
    for interlocutory appeals from class certification orders.
    29
    appeals have agreed.17         Because the decision whether
    17
    See, e.g., New Motor 
    Vehicles, 522 F.3d at 24
    (“It is a
    settled question that some inquiry into the merits at the class
    certification stage is not only permissible but appropriate to the
    extent that the merits overlap the Rule 23 criteria.”); Oscar
    Private Equity Invs. v. Allegiance Telecom, Inc., 
    487 F.3d 261
    ,
    268 (5th Cir. 2007) (“Eisen did not drain Rule 23 of all rigor.
    A district court still must give full and independent weight to
    each Rule 23 requirement, regardless of whether that
    requirement overlaps with the merits.”); Regents of Univ. of
    
    Cal., 482 F.3d at 380
    (“[W]e may address arguments that
    implicate the merits of plaintiffs’ cause of action insofar as those
    arguments also implicate the merits of the class certification
    decision.”); 
    IPO, 471 F.3d at 41
    (“With Eisen properly
    understood to preclude consideration of the merits only when a
    merits issue is unrelated to a Rule 23 requirement, there is no
    reason to lessen a district court’s obligation to make a
    determination that every Rule 23 requirement is met before
    certifying a class just because of some or even full overlap of
    that requirement with a merits issue.”); 
    Gariety, 368 F.3d at 366
    (“[W]hile an evaluation of the merits to determine the strength
    of plaintiffs’ case is not part of a Rule 23 analysis, the factors
    spelled out in Rule 23 must be addressed through findings, even
    if they overlap with issues on the merits.”); 
    Szabo, 249 F.3d at 677
    (“[N]othing in the 1966 amendments to Rule 23, or the
    opinion in Eisen, prevents the district court from looking
    beneath the surface of a complaint to conduct the inquiries
    30
    identified in that rule and exercise the discretion it confers.”);
    see also 7AA Charles Alan Wright, Arthur R. Miller & Mary
    Kay Kane, Federal Practice and Procedure § 1785 (3d ed.
    2005), at 379; Geoffrey P. Miller, Review of the Merits in Class
    Action Certification, 33 Hofstra L. Rev. 51, 63 (2004) (“It
    would be bizarre to conclude that the framers of Rule 23 would
    have set forth a careful set of prerequisites for class certification
    only to deny trial courts the ability to apply those prerequisites
    in a factually-based and reasoned manner.”); New Motor
    
    Vehicles, 522 F.3d at 17
    (“It would be contrary to the ‘rigorous
    analysis of the prerequisites established by Rule 23 before
    certifying a class’ to put blinders on as to an issue simply
    because it implicates the merits of the case.” (quoting Smilow v.
    Sw. Bell Mobile Sys., Inc., 
    323 F.3d 32
    , 38 (1st Cir. 2003))).
    When a district court properly considers an issue overlapping
    the merits in the course of determining whether a Rule 23
    requirement is met, it does not do so in order to predict which
    party will prevail on the merits. Rather, the court “determine[s]
    whether the alleged claims can be properly resolved as a class
    action.” 
    Newton, 259 F.3d at 168
    ; see 
    IPO, 471 F.3d at 39
    n.10.
    A concern for merits-avoidance “should not be talismanically
    invoked to artificially limit a trial court’s examination of the
    factors necessary to a reasoned determination of whether a
    plaintiff has met her burden of establishing each of the Rule 23
    class action requirements.” Castano v. Am. Tobacco Co., 
    84 F.3d 734
    , 744 n.17 (5th Cir. 1996) (quoting Love v. Turlington,
    31
    to certify a class “requires a thorough examination of the factual
    and legal allegations,” 
    id. at 166,
    the court’s rigorous analysis
    may include a “preliminary inquiry into the merits,” 
    id. at 168,
    and the court may “consider the substantive elements of the
    plaintiffs’ case in order to envision the form that a trial on those
    issues would take,” 
    id. at 166
    (quoting 5 Moore’s Federal
    Practice § 23.46[4]) (quotation marks omitted). See 
    id. at 168
    (“In reviewing a motion for class certification, a preliminary
    inquiry into the merits is sometimes necessary to determine
    whether the alleged claims can be properly resolved as a class
    action.”).18 A contested requirement is not forfeited in favor of
    the party seeking certification merely because it is similar or
    even identical to one normally decided by a trier of fact.
    
    733 F.2d 1562
    , 1564 (11th Cir. 1984)) (quotation marks
    omitted).
    18
    Chiang v. Veneman, 
    385 F.3d 256
    , 262 (3d Cir. 2004),
    decided after Newton and Johnston, cited Eisen for the
    proposition that “in determining whether a class will be
    certified, the substantive allegations of the complaint must be
    taken as true.” No supporting analysis of Rule 23 jurisprudence
    accompanied this statement, which contradicts and conflicts
    with Newton, Johnston, and Szabo (which we relied upon in
    Newton). “To the extent that the decision of a later panel
    conflicts with existing circuit precedent, we are bound by the
    earlier, not the later, decision.” United States v. Monaco, 
    23 F.3d 793
    , 803 (3d Cir. 1994).
    32
    Although the district court’s findings for the purpose of class
    certification are conclusive on that topic, they do not bind the
    fact-finder on the merits.19
    The evidence and arguments a district court considers in
    the class certification decision call for rigorous analysis. A
    party’s assurance to the court that it intends or plans to meet the
    requirements is insufficient. See 
    id. at 191
    (“[W]here the court
    finds, on the basis of substantial evidence as here, that there are
    serious problems now appearing, it should not certify the class
    merely on the assurance of counsel that some solution will be
    found.” (quoting Windham v. Am. Brands, Inc., 
    565 F.2d 59
    , 70
    (4th Cir. 1977)) (quotation marks omitted); Wachtel v. Guardian
    Life Ins. Co., 
    453 F.3d 179
    , 184, 186 (3d Cir. 2006) (the
    requirement that a district court include in its class certification
    order “a clear and complete summary of those claims, issues, or
    19
    “[T]he determination as to a Rule 23 requirement is made
    only for purposes of class certification and is not binding on the
    trier of facts, even if that trier is the class certification judge.”
    
    IPO, 471 F.3d at 41
    (citing 
    Gariety, 368 F.3d at 366
    ); see 
    id. at 39
    (“A trial judge’s finding on a merits issue for purposes of a
    Rule 23 requirement no more binds the court to rule for the
    plaintiff on the ultimate merits of that issue than does a finding
    that the plaintiff has shown a probability of success for purposes
    of a preliminary injunction.”); 
    Unger, 401 F.3d at 323
    (“[T]he
    court’s determination for class certification purposes may be
    revised (or wholly rejected) by the ultimate factfinder . . . .”).
    33
    defenses subject to class treatment” provides for the “full and
    clear articulation of the litigation’s contours at the time of class
    certification”).
    Support for our analysis is drawn from amendments to
    Rule 23 that took effect in 2003. First, amended Rule
    23(c)(1)(A) altered the timing requirement for the class
    certification decision. The amended rule calls for a decision on
    class certification “[a]t an early practicable time after a person
    sues or is sued as a class representative,” while the prior version
    had required that decision be made “as soon as practicable after
    commencement of an action.” We recognized in Weiss v. Regal
    Collections, 
    385 F.3d 337
    , 347 (3d Cir. 2004), that this change
    in language, though subtle, reflects the need for a thorough
    evaluation of the Rule 23 factors—for this reason the rule does
    not “require or encourage premature certification
    determinations.” We explained:
    Fed. R. Civ. P. 23 directs that certification
    decisions be made “at an early practicable time.”
    Fed. R. Civ. P. 23(c)(1)(a). This recent
    amendment replaced the language of the old rule:
    The former “‘as soon as practicable’ exaction
    neither reflect[ed] prevailing practice nor
    capture[ed] the many valid reasons that may
    justify deferring the initial certification decision.”
    See Fed. R. Civ. P. 23(c)(1)(a) Advisory
    Committee Notes. . . .
    Allowing time for limited discovery
    34
    supporting certification motions may . . . be
    necessary for sound judicial administration. See
    [
    Newton, 259 F.3d at 166
    ] (“[I]t may be necessary
    for the Court to probe behind the pleadings before
    coming to rest on the certification question.”)
    (quoting 
    [Falcon, 457 U.S. at 160
    ]) . . . .
    
    Id. at 347–48
    n.17; see 
    Gariety, 368 F.3d at 365
    (noting the
    change).20 Relatedly, in introducing the concept of a “trial
    20
    The Advisory Committee’s note explains:
    Time may be needed to gather information
    necessary to make the certification decision.
    Although an evaluation of the probable outcome
    on the merits is not properly part of the
    certification decision, discovery in aid of the
    certification decision often includes information
    required to identify the nature of the issues that
    actually will be presented at trial. In this sense it
    is appropriate to conduct controlled discovery into
    the “merits,” limited to those aspects relevant to
    making the certification decision on an informed
    basis.    Active judicial supervision may be
    required to achieve the most effective balance that
    expedites an informed certification determination
    without forcing an artificial and ultimately
    wasteful division between “certification
    discovery” and “merits discovery.”
    35
    plan,” the Advisory Committee’s 2003 note focuses attention on
    a rigorous evaluation of the likely shape of a trial on the issues:
    Fed. R. Civ. P. 23 advisory committee’s note, 2003
    Amendments.
    As the Standing Committee on Rules of Practice and
    Procedure explained in its report proposing this amendment, the
    new language
    authorizes the more flexible approach many
    courts take to class-action litigation, recognizing
    the important consequences to the parties of the
    court’s decision on certification. The current
    rule’s emphasis on dispatch in making the
    certification decision has, in some circumstances,
    led courts to believe that they are overly
    constrained in the period before certification. A
    certain amount of discovery may be appropriate
    during this period to illuminate issues bearing on
    certification, including the nature of the issues
    that will be tried; whether the evidence on the
    merits is common to the members of the proposed
    class; whether the issues are susceptible to
    class-wide proof; and what trial-management
    problems the case will present.
    Report of the Judicial Conference Committee on Rules of
    Practice and Procedure to the Chief Justice of the United States
    and Members of the Judicial Conference of the United States 10
    (2002) [hereinafter Committee Report].
    36
    A critical need is to determine how the case will
    be tried. An increasing number of courts require
    a party requesting class certification to present a
    “trial plan” that describes the issues likely to be
    presented at trial and tests whether they are
    susceptible of class-wide proof.
    Fed. R. Civ. P. 23 advisory committee’s note, 2003
    Amendments.
    Additionally, the 2003 amendments eliminated the
    language that had appeared in Rule 23(c)(1) providing that a
    class certification “may be conditional.” 21 The Advisory
    Committee’s note explains: “A court that is not satisfied that the
    requirements of Rule 23 have been met should refuse
    certification until they have been met.”         The Standing
    Committee on Rules of Practice and Procedure advised:
    The provision for conditional class certification is
    deleted to avoid the unintended suggestion, which
    some courts have adopted, that class certification
    may be granted on a tentative basis, even if it is
    unclear that the rule requirements are satisfied.
    Committee 
    Report, supra, at 12
    ; see 5 Moore’s Federal Practice
    21
    Although the language allowing for “conditional”
    certification has been removed, Fed. R. Civ. P. 23(c)(1)(C)
    provides that “[a]n order that grants or denies class certification
    may be altered or amended before final judgment.”
    37
    § 23.80[2] (“The 2003 amendment clarifies that courts should
    not grant certification except after searching inquiry, and that
    courts should not rely on later developments to determine
    whether certification is appropriate.”).
    While these amendments do not alter the substantive
    standards for class certification, they guide the trial court in its
    proper task—to consider carefully all relevant evidence and
    make a definitive determination that the requirements of Rule 23
    have been met before certifying a class. See 
    IPO, 471 F.3d at 39
    (2003 amendments “arguably combine to permit a more
    extensive inquiry into whether Rule 23 requirements are met
    than was previously appropriate”); 
    Oscar, 487 F.3d at 267
    (noting that these “subtle changes” reflect that “a district court’s
    certification order often bestows upon plaintiffs extraordinary
    leverage, and its bite should dictate the process that precedes
    it”).
    To summarize: because each requirement of Rule 23
    must be met, a district court errs as a matter of law when it fails
    to resolve a genuine legal or factual dispute relevant to
    determining the requirements.
    2.
    Class certification requires a finding that each of the
    requirements of Rule 23 has been met.22 See Unger, 
    401 F.3d 22
           As the Court of Appeals for the First Circuit has explained,
    [Some] circuits’ use of the term ‘findings’ in this
    38
    at 321 (“The plain text of Rule 23 requires the court to ‘find,’
    not merely assume, the facts favoring class certification.”);
    
    Gariety, 368 F.3d at 365
    (Rule 23(b)(3) requires the court to
    find predominance). Factual determinations necessary to make
    Rule 23 findings must be made by a preponderance of the
    evidence. In other words, to certify a class the district court
    must find that the evidence more likely than not establishes each
    fact necessary to meet the requirements of Rule 23. See
    Teamsters Local 445 Freight Div. Pension Fund v. Bombardier
    Inc., 
    546 F.3d 196
    , 202 (2d Cir. 2008).
    In reviewing a district court’s judgment on class
    certification, we apply the abuse of discretion standard. A
    district court abuses its discretion in deciding whether to certify
    a class action if its “decision rests upon a clearly erroneous
    finding of fact, an errant conclusion of law or an improper
    application of law to fact.” In re Gen. Motors Corp. Pick-Up
    Truck Fuel Tank Prods. Liab. Litig., 
    55 F.3d 768
    , 783 (3d Cir.
    1995) (citation and quotation marks omitted); see 
    Newton, 259 F.3d at 165
    . Under these Rule 23 standards, a district court
    context should not be confused with binding
    findings on the merits. The judge’s consideration
    of merits issues at the class certification stage
    pertains only to that stage; the ultimate factfinder,
    whether judge or jury, must still reach its own
    determination on these issues.
    New Motor 
    Vehicles, 522 F.3d at 24
    .
    39
    exercising proper discretion in deciding whether to certify a
    class will resolve factual disputes by a preponderance of the
    evidence and make findings that each Rule 23 requirement is
    met or is not met, having considered all relevant evidence and
    arguments presented by the parties. The abuse of discretion
    standard requires the judge to exercise sound discretion—failing
    that, the judge’s decision is not entitled to the deference
    attendant to discretionary rulings.
    If a class is certified, “the text of the order or an
    incorporated opinion must include (1) a readily discernible,
    clear, and precise statement of the parameters defining the class
    or classes to be certified, and (2) a readily discernible, clear, and
    complete list of the claims, issues or defenses to be treated on a
    class basis.” 
    Wachtel, 453 F.3d at 187
    ; see Fed. R. Civ. P.
    23(c)(1)(B).
    B.
    Although the District Court properly described the class
    certification decision as requiring “rigorous analysis,” some
    statements in its opinion depart from the standards we have
    articulated. The District Court stated, “So long as plaintiffs
    demonstrate their intention to prove a significant portion of their
    case through factual evidence and legal arguments common to
    all class members, that will now suffice. It will not do here to
    make judgments about whether plaintiffs have adduced enough
    evidence or whether their evidence is more or less credible than
    defendants’.” With respect to predominance, the District Court
    40
    stated that “[p]laintiffs need only make a threshold showing that
    the element of impact will predominantly involve generalized
    issues of proof, rather than questions which are particular to
    each member of the plaintiff class.” (quoting Lumco Indus., Inc.
    v. Jeld-Wen, Inc., 
    171 F.R.D. 168
    , 174 (E.D. Pa. 1997)). As we
    have explained, proper analysis under Rule 23 requires rigorous
    consideration of all the evidence and arguments offered by the
    parties. It is incorrect to state that a plaintiff need only
    demonstrate an “intention” to try the case in a manner that
    satisfies the predominance requirement. Similarly, invoking the
    phrase “threshold showing” risks misapplying Rule 23. A
    “threshold showing” could signify, incorrectly, that the burden
    on the party seeking certification is a lenient one (such as a
    prima facie showing or a burden of production) or that the party
    seeking certification receives deference or a presumption in its
    favor. So defined, “threshold showing” is an inadequate and
    improper standard. “[T]he requirements of Rule 23 must be
    met, not just supported by some evidence.” 
    IPO, 471 F.3d at 33
    ;
    see e.g., 
    id. at 40,
    42 (rejecting the view that a party seeking
    certification need only make “some showing” with respect to the
    Rule 23 requirements).
    Citing Cumberland Farms, Inc. v. Browning-Ferris
    Industries, 
    120 F.R.D. 642
    , 645 (E.D. Pa. 1988), the District
    Court reasoned, “[i]t is well recognized that private enforcement
    of [antitrust] laws is a necessary supplement to government
    action. With that in mind, in an alleged horizontal price-fixing
    conspiracy case when a court is in doubt as to whether or not to
    41
    certify a class action, the court should err in favor of allowing
    the class.” See also Eisenberg v. Gagnon, 
    766 F.2d 770
    , 785
    (3d Cir. 1985) (citing Kahan v. Rosenstiel, 
    424 F.2d 161
    , 169
    (3d Cir. 1970)) (advising that in a “doubtful” case when
    presented with a putative securities class action, court should
    err, if at all, in favor of certification). These statements invite
    error. Although the trial court has discretion to grant or deny
    class certification, the court should not suppress “doubt” as to
    whether a Rule 23 requirement is met—no matter the area of
    substantive law. Accordingly, Eisenberg should not be
    understood to encourage certification in the face of doubt as to
    whether a Rule 23 requirement has been met. Eisenberg pre-
    dates the recent amendments to Rule 23 which, as noted, reject
    tentative decisions on certification and encourage development
    of a record sufficient for informed analysis. See Fed. R. Civ. P.
    23 advisory committee’s note, 2003 Amendments (“A court that
    is not satisfied that the requirements of Rule 23 have been met
    should refuse certification until they have been met.”). We
    recognize the Supreme Court has observed that “[p]redominance
    is a test readily met in certain cases alleging consumer or
    securities fraud or violations of the antitrust laws.” 
    Amchem, 521 U.S. at 625
    . But it does not follow that a court should relax
    its certification analysis, or presume a requirement for
    certification is met, merely because a plaintiff’s claims fall
    within one of those substantive categories. See Fed. R. Civ. P.
    23(b)(3) advisory committee’s note, 1966 Amendment (“Private
    damage claims by numerous individuals arising out of concerted
    antitrust violations may or may not involve predominating
    42
    common questions.”); Robinson v. Tex. Auto. Dealers Ass’n,
    
    387 F.3d 416
    , 420–21 (5th Cir. 2004) (“There are no hard and
    fast rules . . . regarding the suitability of a particular type of
    antitrust case for class action treatment. Rather, the unique facts
    of each case will generally be the determining factor governing
    certification.” (citations and quotation marks omitted)).
    “[A]ctual, not presumed, conformance” with the Rule 23
    requirements remains necessary. 
    Newton, 259 F.3d at 167
    (quoting 
    Falcon, 457 U.S. at 160
    ); see, e.g., E. Tex. Motor
    Freight Sys., Inc. v. Rodriguez, 
    431 U.S. 395
    , 405 (1977)
    (although a putative class may bring a type of claim that
    “typically” involves common questions of law or fact, “careful
    attention to the requirements of [Rule 23] remains . . .
    indispensable”).
    To the extent that the District Court’s analysis reflects
    application of incorrect standards, remand is appropriate. We
    recognize that the able District Court did not have the benefit of
    the standards we have articulated. Faced with complex, fact-
    intensive disputes, trial courts have expended considerable effort
    to interpret and apply faithfully the requirements of Rule 23.
    One important reason for granting interlocutory appeals under
    Fed. R. Civ. P. 23(f) is to address “novel or unsettled questions
    of law” like those presented here. 
    Newton, 259 F.3d at 164
    ; see
    Fed. R. Civ. P. 23 advisory committee’s note, 1998
    Amendments (cases in which “the certification decision turns on
    a novel or unsettled question of law” are among the best
    candidates for interlocutory appeal).
    43
    C.
    Defendants contend the District Court erred as a matter
    of law in failing to consider the expert testimony of defendants’
    expert, Ordover, instead deferring to the opinion of plaintiffs’
    expert, Beyer. Plaintiffs do not dispute that a district court may
    properly consider expert opinion with respect to Rule 23
    requirements at the class certification stage, but maintain that in
    this case the District Court considered and rejected Ordover’s
    opinion and defendants’ arguments based on it.
    In addressing defendants’ Daubert motion to exclude
    Beyer’s opinion, the court discussed whether it should consider
    Ordover’s opinion in deciding whether Beyer’s opinion was
    admissible. The court stated it would be improper to “weigh the
    relative credibility of the parties’ experts”—in other words, to
    weigh Ordover’s opinion against Beyer’s—for the purpose of
    deciding whether to admit or exclude Beyer’s opinion.
    Concluding Beyer’s opinion was admissible, the court denied
    the Daubert motion.          But in addressing the Rule 23
    requirements, the court did not confront Ordover’s analysis or
    his substantive rebuttal of Beyer’s points. Nor did the court
    address Ordover’s finding of substantial price disparities among
    similarly situated purchasers of hydrogen peroxide. The court
    appears to have assumed it was barred from weighing Ordover’s
    opinion against Beyer’s for the purpose of deciding whether the
    requirements of Rule 23 had been met. This was erroneous.
    44
    1.
    Expert opinion with respect to class certification, like any
    matter relevant to a Rule 23 requirement, calls for rigorous
    analysis. See 
    West, 282 F.3d at 938
    .23 It follows that opinion
    testimony should not be uncritically accepted as establishing a
    Rule 23 requirement merely because the court holds the
    testimony should not be excluded, under Daubert or for any
    other reason. See 
    IPO, 471 F.3d at 42
    (rejecting the view that
    “an expert’s testimony may establish a component of a Rule 23
    requirement simply by being not fatally flawed” and instructing
    that “[a] district judge is to assess all of the relevant evidence
    admitted at the class certification stage and determine whether
    each Rule 23 requirement has been met, just as the judge would
    resolve a dispute about any other threshold prerequisite for
    23
    See Kermit Roosevelt III, Defeating Class Certification in
    Securities Fraud Actions, 22 Rev. Litig. 405, 425 (2003)
    (“Critical evaluation of an expert’s opinion as to what
    conclusions the evidence supports will frequently bring courts
    close upon the merits, but it is no more than Rule 23 demands.
    An expert who testifies, for example, that every plaintiff has
    suffered injury is in effect testifying that injury may be
    established by common proof. However, the decision as to
    whether the elements of a claim are susceptible to common
    proof is for the judge and may not be handed off to experts.”
    (footnote omitted)).
    45
    continuing a lawsuit”); 24 
    Blades, 400 F.3d at 569
    –70, 575
    (affirming denial of class certification where the district court
    denied defendants’ Daubert motion and “considered all expert
    testimony offered by both sides in support of or in opposition to
    class certification” and “afforded that testimony such weight as
    [it] deemed appropriate”). Under Rule 23 the district court must
    be “satisfied,” 
    Falcon, 457 U.S. at 161
    , or “persuaded,” 
    IPO, 471 F.3d at 41
    , that each requirement is met before certifying a
    class. Like any evidence, admissible expert opinion may
    persuade its audience, or it may not. This point is especially
    important to bear in mind when a party opposing certification
    offers expert opinion. The district court may be persuaded by
    the testimony of either (or neither) party’s expert with respect to
    whether a certification requirement is met.             Weighing
    conflicting expert testimony at the certification stage is not only
    permissible; it may be integral to the rigorous analysis Rule 23
    demands. See 
    Blades, 400 F.3d at 575
    (“[I]n ruling on class
    certification, a court may be required to resolve disputes
    concerning the factual setting of the case,” including “the
    resolution of expert disputes concerning the import of evidence
    concerning the factual setting—such as economic evidence as to
    business operations or market transactions”); 
    West, 282 F.3d at 24
           The District Court found the Court of Appeals for the
    Second Circuit’s opinion in IPO arguably imposes a higher
    burden on a party seeking certification than our circuit’s case
    law. We find IPO consistent with a proper application of our
    circuit’s standards.
    46
    938 (cautioning that neglecting to resolve disputes between
    experts “amounts to a delegation of judicial power to the
    plaintiffs, who can obtain class certification just by hiring a
    competent expert”); see also Cordes & Co. Fin. Servs. v. A.G.
    Edwards & Sons, Inc., 
    502 F.3d 91
    , 106–07 (2d Cir. 2007)
    (analyzing the opinions of plaintiffs’ and defendants’ experts);
    In re Polymedica Corp. Sec. Litig., 
    432 F.3d 1
    , 5–6, 19 (1st Cir.
    2005) (vacating class certification order but finding no error in
    the “level of inquiry” the district court applied under Rule 23
    when it “went well beyond the four corners of the pleadings,
    considering both parties’ expert reports and literally hundreds of
    pages of exhibits focused on market efficiency”).25
    Resolving expert disputes in order to determine whether
    a class certification requirement has been met is always a task
    for the court—no matter whether a dispute might appear to
    implicate the “credibility” of one or more experts, a matter
    resembling those usually reserved for a trier of fact. Rigorous
    analysis need not be hampered by a concern for avoiding
    25
    In New Motor Vehicles, the Court of Appeals for the First
    Circuit analyzed the opinions of both plaintiffs’ and defendants’
    
    experts. 522 F.3d at 20
    –21. It also observed that in Polymedica
    and In re Xcelera.com Securities Litigation, 
    430 F.3d 503
    (1st
    Cir. 2005), the district court and the court of appeals had
    “rigorously tested the evidence submitted by both sides” with
    respect to the fraud-on-the-market presumption. New Motor
    
    Vehicles, 522 F.3d at 25
    .
    47
    credibility issues; as noted, findings with respect to class
    certification do not bind the ultimate fact-finder on the merits.
    A court’s determination that an expert’s opinion is persuasive or
    unpersuasive on a Rule 23 requirement does not preclude a
    different view at the merits stage of the case.
    That weighing expert opinions is proper does not make
    it necessary in every case or unlimited in scope. As the Court of
    Appeals for the Second Circuit instructed,
    To avoid the risk that a Rule 23 hearing will
    extend into a protracted mini-trial of substantial
    portions of the underlying litigation, a district
    judge must be accorded considerable discretion to
    limit both discovery and the extent of the hearing
    on Rule 23 requirements. But even with some
    limits on discovery and the extent of the hearing,
    the district judge must receive enough evidence,
    by affidavits, documents, or testimony, to be
    satisfied that each Rule 23 requirement has been
    met.
    
    IPO, 471 F.3d at 41
    . In its sound discretion, a district court may
    find it unnecessary to consider certain expert opinion with
    respect to a certification requirement, but it may not decline to
    resolve a genuine legal or factual dispute because of concern for
    an overlap with the merits. Genuine disputes with respect to the
    Rule 23 requirements must be resolved, after considering all
    relevant evidence submitted by the parties. See West, 
    282 F.3d 48
    at 938 (“Tough questions must be faced and squarely decided,
    if necessary by holding evidentiary hearings and choosing
    between competing perspectives.”); 
    Szabo, 249 F.3d at 676
    (district court must “resolve the disputes before deciding
    whether to certify the class”); 
    IPO, 471 F.3d at 41
    (Rule 23 calls
    for “definitive assessment” of its requirements); 
    id. at 42
    (rejecting the view that “a district judge may not weigh
    conflicting evidence and determine the existence of a Rule 23
    requirement just because that requirement is identical to an issue
    on the merits”).
    2.
    Plaintiffs contend the District Court’s acceptance of their
    expert’s opinion was consistent with In re Linerboard Antitrust
    Litigation, 
    305 F.3d 145
    (3d Cir. 2002), an antitrust conspiracy
    action in which we affirmed class certification. There are a
    number of surface similarities between this case and Linerboard.
    Plaintiffs’ expert, Beyer, also appeared as an expert for the
    plaintiffs in Linerboard, and in both cases he presented an
    analysis of the industry and a “structure in pricing” analysis. 
    Id. at 153.
    As in Linerboard, Beyer here proposed to demonstrate
    antitrust impact through the use of “benchmarks” and “multiple
    regression analysis.” 
    Id. at 153–54.
    In affirming the district
    court’s grant of class certification in Linerboard, we concluded
    that Beyer, along with another expert for the plaintiffs,
    “effectively utilized supporting data, including charts and
    exhibits, to authenticate their professional opinions that all class
    members would incur” antitrust impact. 
    Id. at 155.
    49
    In Linerboard we did not address whether such expert
    opinion offered by the party opposing class certification would
    have been properly considered by the district court in the
    exercise of its discretion. But defendants here presented expert
    opinion disputing much of the evidence and argument plaintiffs
    offered for certification—specifically, Ordover disputed Beyer’s
    characterizations of the market and the alleged pricing structure.
    Defendants contend Ordover raised substantial doubts, not
    considered by the District Court, about whether common proof
    would be available for plaintiffs to demonstrate antitrust impact
    at trial.
    We do not question plaintiffs’ general proposition, which
    the District Court accepted, that a conspiracy to maintain prices
    could, in theory, impact the entire class despite a decrease in
    prices for some customers in parts of the class period, and
    despite some divergence in the prices different plaintiffs paid.
    But the question at class certification stage is whether, if such
    impact is plausible in theory, it is also susceptible to proof at
    trial through available evidence common to the class. When the
    latter issue is genuinely disputed, the district court must resolve
    it after considering all relevant evidence. Here, the District
    Court apparently believed it was barred from resolving disputes
    between the plaintiffs’ and defendants’ experts. Rule 23 calls
    for consideration of all relevant evidence and arguments,
    including relevant expert testimony of the parties. Accordingly,
    we will vacate the order certifying the class and remand for
    50
    proceedings consistent with this opinion.26
    D.
    Defendants contend the District Court, by relying on
    Bogosian v. Gulf Oil Corp., 
    561 F.2d 434
    (3d Cir. 1977),
    erroneously presumed the predominance requirement was met.
    In Bogosian, also a Clayton Act § 4 case in which plaintiffs
    sought class certification, the district court had denied class
    certification on the assumption that the issue of antitrust impact
    would have to be proven on an individual, as opposed to
    common, 
    basis. 561 F.2d at 454
    . Finding that assumption
    erroneous, we reasoned that “when an antitrust violation impacts
    upon a class of persons who do have standing, there is no reason
    in doctrine why proof of the impact cannot be made on a
    common basis so long as the common proof adequately
    demonstrates some damage to each individual. Whether or not
    fact of damage can be proven on a common basis therefore
    depends upon the circumstances of each case.” 
    Id. Applying the
    concept, we continued:
    If, in this case, a nationwide conspiracy is proven,
    the result of which was to increase prices to a
    class of plaintiffs beyond the prices which would
    26
    The current record suggests it may be possible to overcome
    some obstacles to class certification by shortening the class
    period or by fashioning sub-classes. See Fed. R. Civ. P.
    23(c)(5).
    51
    obtain in a competitive regime, an individual
    plaintiff could prove fact of damage simply by
    proving that the free market prices would be
    lower than the prices paid and that he made some
    purchases at the higher price. If the price
    structure in the industry is such that nationwide
    the conspiratorially affected prices at the
    wholesale level fluctuated within a range which,
    though different in different regions, was higher
    in all regions than the range which would have
    existed in all regions under competitive
    conditions, it would be clear that all members of
    the class suffered some damage, notwithstanding
    that there would be variations among all dealers
    as to the extent of their damage.
    
    Id. at 455;
    see 
    Newton, 259 F.3d at 179
    n.21 (“In antitrust class
    actions, injury may be presumed when it is clear the violation
    results in harm to the entire class.”); 
    Linerboard, 305 F.3d at 151
    –53.
    In Linerboard, we found a “strong argument [could] be
    made that the Bogosian concept of presumed impact was
    properly applied” on the facts of that case. 
    Id. at 152.
    Plaintiffs
    had alleged a horizontal conspiracy by manufacturers to restrict
    supply and raise prices of linerboard, the paper lining used in
    corrugated cardboard boxes and sheets. 
    Id. Over a
    two-year
    period, defendants allegedly had agreed to idle their plants to
    reduce inventories to a twenty-year low and boost prices. 
    Id. at 52
    150–51. During the two-year class period, prices had risen by
    ninety percent. See 
    id. at 152
    (“Coincident with [defendants’]
    interference with the normal market forces, linerboard prices in
    the eastern United States rose in six consecutive price increases,
    from a low of around $270 to $290 per ton in third quarter 1993
    to $530 per ton by April 1995.”). The record in this case is
    different. Although the price of hydrogen peroxide rose at some
    points during the lengthy class period, the price was lower, not
    higher, at the end of the class period than at the beginning. And
    the evidence, as interpreted by defendants’ expert, shows that
    through much of the class period the production of hydrogen
    peroxide was increasing rather than decreasing. Moreover, there
    was an active dispute between the experts as to the “price
    structure in the industry” to which Bogosian refers. Defendants
    cited, for example, Ordover’s empirical analysis showing
    substantial price disparities among similarly situated customers.
    Accordingly, defendants contended, it was far from “clear the
    violation result[ed] in harm to the entire class,” 
    Newton, 259 F.3d at 179
    n.21. It is not apparent that the District Court
    considered, or believed it had the authority to consider, all the
    evidence in the record with respect to this dispute.
    While the District Court found the Bogosian presumption
    applied, it also relied on Beyer’s analysis. Cf. 
    Linerboard, 305 F.3d at 155
    (“[T]his was not a case where plaintiffs relied solely
    on presumed impact and damages.”). As in Linerboard,
    plaintiffs here stress that they do not rely merely on Bogosian’s
    presumption to support class certification, but also on their
    53
    expert’s analysis. Plaintiffs do not contend a bare allegation of
    a price-fixing conspiracy, in the absence of supporting evidence
    and analysis, suffices to support class certification consistent
    with a proper “rigorous analysis” under Rule 23. We emphasize
    that “[a]ctual, not presumed, conformance” with the Rule 23
    requirements is essential. 
    Newton, 259 F.3d at 167
    (quoting
    
    Falcon, 457 U.S. at 160
    ) 
    Falcon, 457 U.S. at 160
    ; 
    Newton, 259 F.3d at 167
    . Applying a presumption of impact based solely on
    an unadorned allegation of price-fixing would appear to conflict
    with the 2003 amendments to Rule 23, which emphasize the
    need for a careful, fact-based approach, informed, if necessary,
    by discovery. See Fed. R. Civ. P. 23 advisory committee’s note,
    2003 Amendments (“[D]iscovery in aid of the certification
    decision often includes information required to identify the
    nature of the issues that actually will be presented at trial.”).
    The District Court, upon review of all the evidence
    consistent with this opinion, may again consider whether the
    reasoning in Bogosian is compatible with the record of this case.
    See In re Salomon Analyst Metromedia Litig., 
    544 F.3d 474
    ,
    485–86 (2d Cir. 2008) (remanding for opportunity for party
    opposing class certification to present evidence rebutting the
    fraud-on-the-market presumption, because Rule 23 requires a
    “definitive assessment” as to the predominance requirement).
    V.
    For the foregoing reasons, we will vacate the class
    certification order and remand for proceedings consistent with
    54
    this opinion.
    55