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Page Number: 14.0

10 

WAL-MART STORES, INC. v. DUKES 

Opinion of the Court 

erate  common  answers  apt  to  drive  the  resolution  of 
the  litigation.  Dissimilarities  within  the  proposed 
class  are  what  have  the  potential  to  impede  the  gen-
eration of common answers.”  Nagareda, supra, at 132. 

Rule 23 does not set forth a mere pleading standard.  A 
party  seeking  class  certification  must  affirmatively  dem-
onstrate his compliance with the Rule—that is, he must be
prepared  to  prove  that  there  are  in  fact  sufficiently  nu-
merous parties, common questions of law or fact, etc.  We 
recognized in Falcon that “sometimes it may be necessary
for the court to probe behind the pleadings before coming
to rest on the certification question,” 457 U. S., at 160, and 
that certification is proper only if “the trial court is satis-
fied,  after  a  rigorous  analysis,  that  the  prerequisites  of 
Rule 23(a) have been satisfied,” id., at 161; see id., at 160 
(“[A]ctual,  not  presumed,  conformance  with  Rule  23(a) 
remains  . . .  indispensable”).    Frequently  that  “rigorous 
analysis”  will  entail  some  overlap  with  the  merits  of 
the  plaintiff ’s  underlying  claim.    That  cannot  be  helped. 
“ ‘[T]he  class  determination  generally  involves  considera-
tions  that  are  enmeshed  in  the  factual  and  legal  issues
comprising the plaintiff ’s cause of action.’ ”  Falcon, supra, 
at  160  (quoting  Coopers  &  Lybrand  v.  Livesay,  437  U. S. 
463, 469 (1978); some internal quotation marks omitted).6 
—————— 

6 A statement in one of our prior cases, Eisen v. Carlisle & Jacquelin, 
417  U. S.  156,  177  (1974),  is  sometimes  mistakenly  cited  to  the  con-
trary: “We find 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.”  But in that case, the judge had conducted a preliminary
inquiry into the merits of a suit, not in order to determine the propriety 
of certification under Rules 23(a) and (b) (he had already done that, see 
id.,  at  165),  but  in  order  to  shift  the  cost  of  notice  required  by  Rule 
23(c)(2) from the plaintiff to the defendants.  To the extent the quoted
statement  goes  beyond  the  permissibility  of  a  merits  inquiry  for  any
other  pretrial  purpose,  it  is  the  purest  dictum  and  is  contradicted  by 
our other cases.