FOR PUBLICATION

UNITED STATES COURT OF APPEALS

FOR THE NINTH CIRCUIT

SHIRLEY “RAE” ELLIS; LEAH 

HORSTMAN; ELAINE SASAKI, on

behalf of themselves and all others No. 07-15838

similarly situated, D.C. No.

Plaintiffs-Appellees,  CV-04-03341-MHP

v. OPINION

COSTCO WHOLESALE CORPORATION,

Defendant-Appellant. 

Appeal from the United States District Court

for the Northern District of California

Marilyn H. Patel, District Judge, Presiding

Argued on April 14, 2008 and

Resubmitted on September 9, 2011

San Francisco, California

Filed September 16, 2011

Before: Ronald M. Gould, Richard R. Clifton, and

N. Randy Smith, Circuit Judges.

Opinion by Judge N.R. Smith

17693
COUNSEL

Kenwood C. Youmans, David D. Kadue, David B. Ross, Gerlad L. Maatman, & Thomas J. Wybenga, Seyfarth Shaw LLP,

New York, New York, for defendant-appellant Costco

Wholesale Corporation.

Brad Seligman & Jocelyn D. Larkin, The Impact Fund,

Berkeley, California; Steve Stemerman, Elizabeth A. Lawrence, & Sarah Varela, Davis, Cowell & Bowe, San Francisco, California; Bill Lann Lee, Lindsay Nako, & Julia

Campins, Lewis, Feinberg, Lee, Renaker & Jackson, P.C.,

Oakland, California, for plaintiffs-appellees Shirley “Rae”

Ellis, Leah Horstman, & Elaine Sasaki.

OPINION

N.R. Smith, Circuit Judge:

Costco Wholesale Corporation appeals the district court’s

order granting class certification in a class action brought by

Shirley “Rae” Ellis, Leah Horstman, and Elaine Sasaki (collectively Plaintiffs). In the class action, Plaintiffs allege that

Costco’s promotional practices discriminate based on gender.

Because we granted Costco permission to file an interlocutory

appeal, our jurisdiction arises under 28 U.S.C. § 1292(e). We

affirm in part, vacate in part, and remand.

This complicated case requires us to consider a number of

issues relating to class certification. Several of these issues

have recently been clarified by the Supreme Court’s decision

in Wal-Mart Stores, Inc. v. Dukes, 131 S. Ct. 2541, 2551

(2011). Given this new precedent altering existing case law,

we must remand to the district court. See Associated Builders

& Contractors, Inc. v. Curry, 68 F.3d 342, 343 (9th Cir.

1995). Specifically, we take the following actions: (1)

ELLIS v. COSTCO WHOLESALE CORP. 17697
Because at least one named Plaintiff (Sasaki) alleges a concrete injury that is both directly traceable to Costco’s allegedly discriminatory practices and is redressable by both

injunctive relief and monetary damages, see Bates v. United

Parcel Serv., Inc., 511 F.3d 974, 985 (9th Cir. 2007) (en

banc), we affirm the district court’s ruling on standing. (2) We

vacate and remand the district court’s ruling as to “commonality” under Rule 23(a) of the Federal Rules of Civil Procedure. The district court failed to conduct the required

“rigorous analysis” to determine whether there were common

questions of law or fact among the class members’ claims.

Gen. Tel. Co. of the Sw. v. Falcon, 457 U.S. 147, 161 (1982).

Instead it relied on the admissibility of Plaintiffs’ evidence to

reach its conclusion on commonality. (3) We vacate the district court’s ruling as to “typicality” under Rule 23(a), because

the district court failed to consider the effect that defenses

unique to the named Plaintiffs’ claims have on that question.

Hanon v. Dataproducts Corp., 976 F.2d 497, 508 (9th Cir.

1992). (4) We affirm the district court’s ruling that Sasaki is

an adequate class representative under Rule 23(a). As a current employee who continues to be denied promotion, Sasaki

has incentive to vigorously pursue injunctive relief as well as

monetary damages on behalf of all the class members. Hanlon

v. Chrysler Corp., 150 F.3d 1011, 1020 (9th Cir. 1998). However, we vacate the district court’s finding that Ellis and

Horstman could adequately represent the class, because they

were former employees and had no incentive to pursue

injunctive relief. (5) In light of Wal-Mart’s rejection of the

“predominance” test, 131 S. Ct. at 2557-59, the district court

must consider whether the claims for various forms of monetary relief will require individual determinations and are

therefore only appropriate for a Rule 23(b)(3) class. Thus, we

vacate the district court’s certification of the class under Rule

23(b)(2).

17698 ELLIS v. COSTCO WHOLESALE CORP.
FACTUAL BACKGROUND

I. The Parties

A. Costco

Costco is a corporation headquartered in Issaquah, Washington. Costco operates over 350 warehouse-style retail establishments (warehouses). These warehouses sell items ranging

from groceries to electronics. Within each Costco warehouse,

the management structure consists of a General Manager

(GM), two to three Assistant General Managers (AGM), and

three to four Senior Staff Managers. A Costco GM is responsible for the entire operation of his or her respective warehouse and earns an average salary of approximately $116,000,

plus stock and bonuses. Costco AGMs are second in command within each warehouse and earn an average salary of

approximately $73,000, plus stock and bonuses. Costco’s

Senior Staff Managers are divided into four categories: Front

End Managers, Administration Managers, Receiving Managers, and Merchandise Managers.1

 Front End Managers oversee cashiers, membership/marketing personnel, cart staff, and

other employees who deal directly with Costco members.

Administration Managers manage administrative functions

such as payroll and human resources. Receiving Managers

oversee stocking of all incoming items from the receiving

dock to the shelves. Merchandising Managers oversee lower

level managers and are responsible for planning floor displays

to maximize sales. 

Costco promotes almost entirely from within its organization. Only current Costco AGMs are eligible for GM positions. Costco does not have any written policy explaining to

employees the criteria to be considered for promotion to GM

1Most warehouses employ four Senior Staff Managers—one for each of

the four Senior Staff Manager positions. However, in some larger warehouses, one of the AGMs assumes the role of Administration Manager. 

ELLIS v. COSTCO WHOLESALE CORP. 17699
or AGM, though candidates are promoted from a list of promotable candidates. Costco does not have written guidelines

explaining how candidates should be selected for the promotable lists and does not regularly inform employees about the

existence of such lists. Costco does not require that more than

one candidate be considered for any particular opening or that

a performance evaluation or any other documents be reviewed

before a recommended candidate is approved. Costco also

lacks a consistent practice for interviewing potential candidates for GM and AGM openings. Costco does not keep

records regarding the selection process.

Costco employs a different promotion procedure for Senior

Staff Managers. Costco fills the majority of Senior Staff openings by rotating managers among the four Senior Staff positions. This rotation is part of Costco’s philosophy and, in

Costco’s opinion, trains and develops managers for future

advancement by exposing them to different aspects of Costco’s operations. Like the GM and AGM promotion procedures, Costco has no written guidelines regarding rotation of

Senior Staff Managers.

B. Ellis

Costco hired Shirley Ellis as an AGM in 1998. Prior to

joining Costco, Ellis worked for nearly 20 years in retail management, including five years as a general manager for Sam’s

Club (Costco’s chief competitor). According to Ellis, she left

Sam’s Club, because she was actively recruited by Costco and

promised promotion to GM within a year. On the other hand,

Costco claims that it recruited Ellis because she misrepresented herself as a star at Sam’s Club, when she had, in fact,

lost her job for poor performance. 

In Ellis’s first year with Costco, she transferred locations

twice in order to further her goal of promotion to GM. During

this time, several GM positions became available, but she did

not learn of the openings until after they were filled. In 2000,

17700 ELLIS v. COSTCO WHOLESALE CORP.
Ellis transferred to Colorado to assist her sick mother.

According to Ellis, a supervisor told her that it would not hurt

her chances for promotion. After six months, Ellis notified

Costco that she was again able to relocate anywhere as a GM.

In 2002, Ellis sent a letter to her supervisors expressing a

“burning desire” to help Costco be successful and advance

within the company, asking how the GM selection process

worked, where she stood as a candidate for promotion, and

what she needed to do to become a GM. 

In October 2002, Ellis, while still employed with Costco as

an AGM, filed a gender discrimination charge with the Equal

Employment Opportunity Commission (EEOC), alleging that

she had been passed over for promotion to GM because she

was female. Ellis left Costco in November 2004.

C. Horstman

Leah Horstman worked for Costco for more than 23 years

beginning in 1981. In 1996, after 15 years with Costco, Horstman was promoted to be a Senior Staff Manager. By 2000,

Horstman had rotated through the Administrative Manager,

Merchandise Manager, and Receiving Manager positions. She

had earlier worked as an Assistant Front End Manager, but

did not rotate to the Front End Manager position because of

scheduling conflicts and her duties as a single mother with

two young daughters. 

Throughout her career with Costco, Horstman repeatedly

expressed her interest in advancing to AGM and GM and

questioned supervisors about the requirements for both positions. Heeding the advice of a supervisor, Horstman also

transferred to a high-volume store and expressed a willingness

to move from California to Texas in order to become an

AGM. However, in her final three annual self-performance

reviews, Horstman indicated that her goal was to stay in a

position similar to that which she held at the time for three to

five years so that she could balance her family life and then

ELLIS v. COSTCO WHOLESALE CORP. 17701
to continue her advancement to AGM and GM. Horstman

filed a discrimination charge with the EEOC in October 2003

and resigned in June 2004.

D. Sasaki

Elaine Sasaki began working for Costco in 1985. Sasaki

advanced to become a Senior Staff Manager within four

years. She received consistently high performance reviews,

and her GM first indicated that she was ready to be promoted

to AGM in 1993. Although Sasaki offered to transfer to

places as far away as Hong Kong, she was not promoted to

AGM until 1996. Sasaki is currently an AGM in Visalia, California. 

Since Sasaki was promoted to AGM in 1996, she has not

been selected for at least eight GM positions. She claims she

was not aware of any of these openings until after they were

filled. Sasaki has relocated four times to improve her chances

of promotion to GM. In September 2003, Sasaki wrote to

Costco’s director of human resources expressing her concern

that she had not been promoted because of her gender. At

least some of her concern stems from an incident in which she

claimed to rebuff the advances of her regional Senior Vice

President in a hotel elevator and was later told by him that he

holds her to higher standards than other AGMs. According to

Costco, Sasaki has not been promoted because both her performance appraisals and her self-evaluations identify areas for

improvement. Further, she has never ranked high on Costco’s

GM promotable list. Sasaki filed a gender discrimination

charge with the EEOC on March 1, 2005. She remains

employed as an AGM at Costco.

II. Procedural History

The EEOC dismissed Ellis’s charge of gender discrimination, after which Ellis filed suit in federal district court “on

behalf of a Title VII class of all women employed by Costco

17702 ELLIS v. COSTCO WHOLESALE CORP.
in the United States denied promotion to [AGM] and/or [GM]

positions.” Ellis’s complaint sought class-wide injunctive

relief, lost pay, and compensatory and punitive damages. Her

second amended complaint included Horstman and Sasaki as

named Plaintiffs. In August 2006, Plaintiffs filed a motion for

class certification under Rule 23(b)(2) and (b)(3) of the Federal Rules of Civil Procedure supported by numerous declarations, deposition transcripts, and Costco company documents.

Plaintiffs also submitted the declarations of three experts in

support of their class certification motion: statistician Dr.

Richard Drogin; labor economist Dr. Marc Bendick; and sociologist Dr. Barbara Reskin. Dr. Drogin concluded that female

employees are promoted at a slower rate and are underrepresented at the AGM and GM levels relative to their male

peers. Dr. Bendick concluded that female Costco employees

are under-represented in the Senior Staff Manager, AGM, and

GM positions relative to female employees in similar positions at comparable companies. Dr. Reskin concluded that

Costco has a pervasive culture of gender stereotyping and

paternalism. 

Costco opposed class certification and filed 200 employee

declarations in support. Costco additionally submitted declarations of its own experts, most notably, Dr. Ali Saad, a statistician and labor economist. Dr. Saad concluded that women

are not under-represented at Costco and that any gender disparities, if they exist, are confined to two regions. Costco

offered additional expert declarations concluding that gender

disparities, if they exist, are based upon factors such as

women’s lack of interest in jobs requiring early morning

hours. Costco also filed three separate motions to strike Plaintiffs’ experts, supported by Costco’s expert declarations challenging the relevance and reliability of Plantiffs’ experts’

analysis and conclusions. 

On January 11, 2007, the district court filed a 37-page order

granting Plaintiffs’ motion to certify a class. The district court

certified a class that “consists of all current and former female

ELLIS v. COSTCO WHOLESALE CORP. 17703
Costco employees nationwide who have been denied promotion to GM or AGM or denied promotion to Senior Staff positions since January 3, 2002.” Ellis v. Costco Wholesale Corp.,

240 F.R.D. 627, 652 (N.D. Cal. 2007). Because the district

court certified a class broader than the class requested by Plaintiffs,2

 the parties stipulated to a narrower class definition that

consists of “all women employed by Costco on or after January 3, 2002 in a U.S. warehouse (including Puerto Rico) who,

at any time, have been employed at Costco as a Senior Staff

Manager . . . or [AGM]. The class includes women who have

been promoted to [GM] or [AGM] since January 3, 2002.”

3

Stipulation and Order Regarding Class Definition, Class

Notice and For Regulation of Costco’s Communications 2.

The district court found that all of the requirements of Rule

23(a)—numerosity, commonality, typicality, and adequacy—

had been satisfied. Id. at 638-42. It further found that Rule

23(b)(2)4 was satisfied, ruling that signed statements from the

Plaintiffs proved their predominant intent in filing suit was to

recover injunctive relief. Id. at 642-43. It dismissed Costco’s

arguments that Plaintiffs’ claims for punitive and compensatory damages precluded such a finding. Id. at 643. It did not

consider the fact that two of the named Plaintiffs—Ellis and

Horstman—were no longer employees of Costco at the time

of the filing of the complaint in making its determination. 

As part of its order, the district court ruled on Costco’s

motions to strike Plaintiffs’ experts. Id. at 644-51. The district

2The class certified by the district court was broader than that sought by

Plaintiffs because it included those employees who had been denied promotion to Senior Staff positions. 

3Costco did not stipulate to certification of the class, only to narrowing

the district court’s description of the class assuming that it was properly

certified. 

4Although Plaintiffs requested certification under both Rule 23(b)(2)

and (b)(3), the district court did not address certifying the class under

(b)(3). 

17704 ELLIS v. COSTCO WHOLESALE CORP.
court granted in part and denied in part Costco’s motion

regarding Dr. Drogin, striking Dr. Drogin’s conclusion

regarding the average number of years required to reach

AGM because of the dates Dr. Drogin used to conduct his

analysis. Id. at 648-49. The district court denied Costco’s

motions regarding Dr. Bendick and Dr. Reskin. Id. at 651. 

Costco then sought leave to file an interlocutory appeal,

alleging that the district court committed numerous errors by

certifying the class. On May 14, 2007, we granted permission

to appeal. 

ANALYSIS

I. Standing

Costco argues that the district court abused its discretion by

certifying the class, because Plaintiffs lack standing to seek

injunctive relief. “Standing is a threshold matter central to our

subject matter jurisdiction.” Bates, 511 F.3d at 985. We

review the district court’s factual findings under the clearly

erroneous standard and review the district court’s determination of standing de novo. Lozano v. AT&T Wireless Servs.,

Inc., 504 F.3d 718, 725 (9th Cir. 2007). In a class action, the

plaintiff class bears the burden of showing that Article III

standing exists. Bates, 511 F.3d at 985. “[S]tanding requires

that (1) the plaintiff suffered an injury in fact, i.e., one that is

sufficiently concrete and particularized and actual or imminent, not conjectural or hypothetical, (2) the injury is fairly

traceable to the challenged conduct, and (3) the injury is

likely to be redressed by a favorable decision.” Id. (quoting

Lujan v. Defenders of Wildlife, 504 U.S. 555, 560-61 (1992))

(internal quotation marks omitted). Plaintiffs must show

standing with respect to each form of relief sought. Id. Standing exists if at least one named plaintiff meets the requirements. Id.

[1] In order to satisfy the Lujan requirements, “[t]he plaintiff must demonstrate that he has suffered or is threatened

ELLIS v. COSTCO WHOLESALE CORP. 17705
with a concrete and particularized legal harm, coupled with a

sufficient likelihood that he will again be wronged in a similar

way.” Id. (internal citations and quotation marks omitted).

“Past wrongs do not in themselves amount to a real and

immediate threat of injury necessary to make out a case or

controversy” but “are evidence bearing on whether there is a

real and immediate threat of repeated injury.” Id. (internal

citations, alterations, and quotation marks omitted). For Plaintiffs to have standing here, the claimed threat of injury must

be likely to be redressed by the prospective injunctive relief.

Id.

[2] Sasaki satisfies all aspects of the standing requirements. The parties’ stipulated class description includes

female Costco employees who have been denied promotion to

AGM or GM. Sasaki has been denied promotion to GM. Costco’s failure to promote Sasaki (a current AGM) to GM is a

“concrete and particularized” harm, because the injury affects

her “in a personal and individual way.” Lujan, 504 U.S. at

560 n.1. Additionally, the “crux” of Plaintiffs’ lawsuit is that

the “harm alleged is directly traceable” to Costco’s promotion

practices and general corporate culture, which Plaintiffs allege

are discriminatory to women. See Bates, 511 F.3d at 986

(citation omitted). Sasaki can also show that there is a significant likelihood that she will be wronged again in a similar

way. See id. at 985. Sasaki has been employed as an AGM for

twelve years. Despite her expressed interest in becoming a

GM, coupled with numerous relocations to avail herself of

that opportunity, Sasaki has been passed over for promotion

at least eight times. Because Costco’s challenged promotion

practices for GM and AGM positions have not changed,5 there

5Costco’s adoption of the Rothman Workplan does not change this

result. The Workplan was adopted in response to criticisms that Costco’s

inconsistent promotion practices allowed for favoritism and individual

biases. However, it appears the Rothman Workplan only changed promotion practices as to the four Senior Staff jobs, but not as to AGM or GM

positions. 

17706 ELLIS v. COSTCO WHOLESALE CORP.
is a likelihood that Costco will continue to fail to promote

Sasaki. Finally, if Costco’s allegedly discriminatory policies

are enjoined, Sasaki’s claimed threat of being passed over for

promotion due to her gender is likely to be redressed. See

Bates, 511 F.3d at 985. 

[3] Costco, nevertheless, argues that Sasaki lacks standing

because, as a current AGM, she cannot challenge the denial

of AGM promotions. This argument more appropriately

addresses whether Sasaki’s claim is typical of other class

members, which we address below. Sasaki’s status as a current AGM does not preclude her from meeting Lujan’s standing requirements, given that the purported class also includes

women denied promotion to GM. Because only one named

Plaintiff must meet the standing requirements, the district

court did not err in finding that Plaintiffs have standing. 

II. Rule 23(a) 

[4] The district court held that Plaintiffs established all

four Rule 23(a) factors necessary for class certification.

Costco argues that the district court abused its discretion by

finding that Plaintiffs established commonality, typicality, and

adequacy of representation. However, Costco does not contest

the district court’s holding that Plaintiffs established numerosity.

Parties seeking class certification bear the burden of demonstrating that they have met each of the four requirements of

Federal Rule of Civil Procedure 23(a) and at least one of the

requirements of Rule 23(b). Zinser v. Accufix Research Inst.,

Inc., 253 F.3d 1180, 1186 (9th Cir.), amended by 273 F.3d

1266 (9th Cir. 2001). Here, the district court certified the class

under Rule 23(b)(2).

Rule 23(a) requires parties seeking class certification to

establish: (1) that the class is so large that joinder of all members is impracticable (numerosity); (2) that there are one or

ELLIS v. COSTCO WHOLESALE CORP. 17707
more questions of law or fact common to the class (commonality); (3) that the named parties’ claims are typical of the

class (typicality); and (4) that the class representatives will

fairly and adequately protect the interests of other members of

the class (adequacy of representation). Fed. R. Civ. P. 23(a).

We review the district court’s decision regarding class certification for abuse of discretion. Lozano, 504 F.3d at 725.

“The district court abuses its discretion if its certification

order is premised on impermissible legal criteria.” Id. (citing

Moore v. Hughes Helicopters, Inc., 708 F.2d 475, 479 (9th

Cir. 1983)). 

The United States Supreme Court requires district courts to

engage in a “rigorous analysis” of each Rule 23(a) factor

when determining whether plaintiffs seeking class certification have met the requirements of Rule 23. Falcon, 457 U.S.

at 161. The Supreme Court has also noted that the

“[e]valuation of many of the questions entering into determination of class action questions is intimately involved with the

merits of the claims. The typicality of the representative’s

claims or defenses, the adequacy of the representative, and the

presence of common questions of law or fact are obvious

examples.” Coopers & Lybrand v. Livesay, 437 U.S. 463, 469

n.12 (1978) (internal citation and quotation marks omitted).

When considering class certification under Rule 23, district

courts are not only at liberty to, but must perform “a rigorous

analysis [to ensure] that the prerequisites of Rule 23(a) have

been satisfied.” Wal-Mart, 131 S. Ct. at 2551 (internal citation

and quotation marks omitted). In many cases, “that ‘rigorous

analysis’ will entail some overlap with the merits of the plaintiff ’s underlying claim. That cannot be helped.” Id. Here, the

question of commonality overlaps with Plaintiffs’ claim that

Costco’s system of promotion and corporate culture constitutes a pattern or practice of discrimination. 

17708 ELLIS v. COSTCO WHOLESALE CORP.
A. Commonality

Costco challenges the district court’s finding of commonality, arguing primarily that the district court failed to conduct

the required “rigorous analysis” and impermissibly declined

to resolve numerous disputed issues of law and fact necessary

to determine whether Plaintiffs established commonality.

Costco argues that the district court erred by relying on the

declarations of Plaintiffs’ experts to establish commonality.6

We agree. Because the district court premised its certification

order on improper legal criteria, Lozano, 504 F.3d at 725, the

district court abused its discretion. We vacate its order as to

commonality and remand for the district court to reconsider

this issue consistent with our holding today.

[5] To show commonality, Plaintiffs must demonstrate that

there are questions of fact and law that are common to the

class. Fed. R. Civ. P. 23(a)(2). The requirements of Rule

23(a)(2) have “been construed permissively,” and “[a]ll questions of fact and law need not be common to satisfy the rule.”

Hanlon, 150 F.3d at 1019. However, it is insufficient to

6

In the district court, Costco moved to strike the entirety of Plaintiffs’

three expert declarations. With the exception of Dr. Drogin’s conclusion

regarding the average number of years required to reach AGM, the district

court held that Plaintiffs’ experts’ declarations were admissible. It noted

that, while Costco’s arguments may eventually render the declarations

unconvincing at trial, they did not render the declarations inadmissible. On

appeal, Costco does not argue that the district court abused its discretion

by failing to strike Plaintiffs’ experts’ declarations. Instead, it devotes a

substantial portion of its opening brief to arguments challenging the validity of the conclusions in Plaintiffs’ experts’ declarations, but only in the

context of challenging the district court’s conclusion that Plaintiffs had

established commonality under Rule 23(a). We “will not ordinarily consider matters on appeal that are not specifically and distinctly argued in

appellant’s opening brief . . . .” Miller v. Fairchild Indus., Inc., 797 F.2d

727, 738 (9th Cir. 1986). Therefore, we affirm the district court’s decision

to not strike Plaintiffs’ experts’ declarations and consider Costco’s challenges to Plaintiffs’ experts only in our review of the district court’s Rule

23(a) analysis. 

ELLIS v. COSTCO WHOLESALE CORP. 17709
merely allege any common question, for example, “Were

Plaintiffs passed over for promotion?” See Wal-Mart, 131 S.

Ct. at 2551-52. Instead, they must pose a question that “will

produce a common answer to the crucial question why was I

disfavored.” Id. at 2552; see also id. at 2551 (“What matters

to class certification is not the raising of common ‘questions’

. . . but, rather the capacity of a classwide proceeding to generate common answers apt to drive the resolution of the litigation.” (internal citation, alteration, and quotation marks

omitted)). In other words, Plaintiffs must have a common

question that will connect many individual promotional decisions to their claim for class relief. 

The precise standard the district court used to evaluate

commonality is difficult to discern from its order. The district

court began by citing Blackie v. Barrack, 524 F.2d 891, 901

n.17 (9th Cir. 1975), for the proposition that “in adjudicating

a motion for class certification, the court accepts the allegations in the complaint as true so long as those allegations are

sufficiently specific to permit an informed assessment as to

whether the requirements of Rule 23 have been satisfied.”

Ellis, 240 F.R.D. at 635. It proceeded to note, relying on

Eisen v. Carlisle & Jacquelin, 417 U.S. 156, 177-78 (1974),

that the merits of the class members’ substantive claims were

generally irrelevant to its inquiry and that it should not inquire

into the merits of the suit during the certification process. Id.

However, later in its order, the district court seemed to qualify

its position by noting that it may consider the merits to the

extent that they overlap with class certification issues, relying

on In re Initial Public Offering Securities Litigation, 471 F.3d

24 (2d Cir. 2006). Id. After all this, the district court stated in

its analysis of commonality, that “[t]o the extent that the parties’ commonality arguments overlap with the merits, the

court has evaluated all relevant evidence to determine whether

commonality has been established.” Id. at 638. This statement

mitigates the district court’s earlier erroneous suggestions that

it may (but not must) consider the merits to the extent they

overlap with the commonality issue.

17710 ELLIS v. COSTCO WHOLESALE CORP.
[6] At best, it was unclear what standard the district court

used. Regardless of whether the district court applied an erroneous standard, we take this opportunity to clarify the correct

standard. As we explained above, the merits of the class members’ substantive claims are often highly relevant when determining whether to certify a class. More importantly, it is not

correct to say a district court may consider the merits to the

extent that they overlap with class certification issues; rather,

a district court must consider the merits if they overlap with

the Rule 23(a) requirements. Wal-Mart, 131 S. Ct. at 2551-52;

Hanon, 976 F.2d at 509. 

In Wal-Mart, for example, the Supreme Court considered

whether the statistical and sociological studies cited by the

plaintiffs were sufficient to link the alleged discriminatory

practice to harm suffered by the entire class. 131 S. Ct. at

2553-55. In that case, the alleged discriminatory practice was

the exercise of discretion by thousands of individual managers

throughout the country. Id. The only evidence of a nationwide

practice of discrimination was Wal-Mart’s “strong corporate

culture that makes it vulnerable to gender bias.” Id. (internal

quotation marks omitted). However, plaintiffs’ expert was

unable to show to what extent this was true—it was unclear

whether “0.5 percent or 95 percent of the employment decisions” were based on this alleged bias. Id. at 2554. Without

some evidence of the extent of the bias, no “common mode

of exercising discretion that pervades the entire company”

(and thus no common question) had been shown. See id. at

2554-55. 

Part of the confusion over the standard applied by the district court in this case stems from the fact that the district

court addressed Costco’s objections to Plaintiffs’ experts in

both its commonality analysis and its analysis of Costco’s

motions to strike. As the district court noted, the parties

staged a battle of the experts over the issue of commonality.

In its analysis of Costco’s motions to strike, the district court

correctly applied the evidentiary standard set forth in Daubert

ELLIS v. COSTCO WHOLESALE CORP. 17711
v. Merrell Dow Pharms., Inc., 509 U.S. 579, 597 (1993). Cf.

Wal-Mart, 131 S. Ct. at 2553-54 (doubting proposition that

Daubert did not apply to the certification stage). Under Daubert, the trial court must act as a “gatekeeper” to exclude junk

science that does not meet Federal Rule of Evidence 702’s

reliability standards by making a preliminary determination

that the expert’s testimony is reliable. Kumho Tire Co. v. Carmichael, 526 U.S. 137, 145, 147-49 (1999). Daubert does not

require a court to admit or to exclude evidence based on its

persuasiveness; rather it requires a court to admit or exclude

evidence based on its scientific reliability and relevance. 509

U.S. at 589-90. Thus, an expert’s “inference or assertion must

be derived by the scientific method” to be admissible. Id. at

590. A trial court has broad latitude not only in determining

whether an expert’s testimony is reliable, but also in deciding

how to determine the testimony’s reliability. Kumho Tire, 526

U.S. at 152.

[7] However, the district court seems to have confused the

Daubert standard it correctly applied to Costco’s motions to

strike with the “rigorous analysis” standard to be applied

when analyzing commonality. Instead of judging the persuasiveness of the evidence presented, the district court seemed

to end its analysis of the plaintiffs’ evidence after determining

such evidence was merely admissible. For example, the district court stated that, although “Costco challenges the propriety of using aggregate data,” such “arguments attack the

weight of the evidence and not its admissibility.” Ellis, 240

F.R.D. at 639. Therefore, to the extent the district court limited its analysis of whether there was commonality to a determination of whether Plaintiffs’ evidence on that point was

admissible, it did so in error. 

Plaintiffs introduced expert declarations to establish that:

(1) female employees are promoted at a slower rate and are

underrepresented at the AGM and GM levels relative to their

male peers; (2) female Costco employees are underrepresented in the Senior Staff Manager, AGM, and GM posi17712 ELLIS v. COSTCO WHOLESALE CORP.
tions relative to female employees in similar positions at comparable companies; and (3) Costco has a pervasive culture of

gender stereotyping and paternalism. Costco offered its own

evidence to show that: (1) “women are not underrepresented

at Costco and that any gender disparities, if they exist, are

confined to two regions of Costco;” and (2) “gender disparities, if they exist, are based upon factors, such as women’s

lack of interest in jobs requiring early morning hours, which

are unrelated to Costco’s culture and promotion processes.”

Id. at 638.

[8] As an initial matter, we agree that the district court was

not required to resolve factual disputes regarding: (1) whether

women were in fact discriminated against in relevant managerial positions at Costco, or (2) whether Costco does in fact

have a culture of gender stereotyping and paternalism. However, the district court was required to resolve any factual disputes necessary to determine whether there was a common

pattern and practice that could affect the class as a whole.

7

 If

there is no evidence that the entire class was subject to the

same allegedly discriminatory practice, there is no question

common to the class. In other words, the district court must

determine whether there was “significant proof that [Costco]

operated under a general policy of discrimination.” Wal-Mart,

131 S. Ct. at 2553 (alteration omitted).8

7For example, the parties dispute whether promotional decisions for

AGMs were made by the GM of the local warehouse, or were made or

strongly influenced by upper management at Costco headquarters. If the

decisions were made at the local warehouse, Plaintiffs likely cannot show

this decisionmaking process affected the class as a whole, since “demonstrating the invalidity of one manager’s use of discretion will do nothing

to demonstrate the invalidity of another’s. A party seeking to certify a

nationwide class will be unable to show that all the employees’ Title VII

claims will in fact depend on the answers to common questions.” WalMart, 131 S. Ct. at 2554. 

8Accordingly, we dispose of most of Costco’s arguments on this point.

Costco seems to equate a “rigorous analysis” with an in-depth examination

of the underlying merits—i.e., whether Costco was in fact discriminating

ELLIS v. COSTCO WHOLESALE CORP. 17713
Whether gender disparities are confined to only two regions

of Costco’s eight regions, for example, addresses precisely the

question of whether there are common questions of law and

fact among the putative class members. If, as Plaintiffs allege,

promotion decisions are based on the biased attitudes of the

CEO and upper management, one would expect disparities in

all, or at least most, regions. A disparity in only 25% of the

regions, however, would not show that “discrimination manifested itself in . . . promotion practices in the same general

fashion,” Wal-Mart, 131 S. Ct. at 2553, throughout Costco—

which is necessary to show commonality in a nationwide

class. If no such nationwide discrimination exists, Plaintiffs

would face an exceedingly difficult challenge in proving that

there are questions of fact and law common to the nationwide

class. 

[9] The district court failed to engage in a “rigorous analysis” on this point. For example, Dr. Saad, Costco’s expert,

concluded that any gender disparities, if they exist, are confined to two regions. The district court concluded that Dr.

Saad’s analysis was “relevant and reliable for the purposes of

against women. See, e.g., Costco’s Opening Br. 21 (“[T]here is no commonality absent (a) statistical proof of under-promotion of women and (b)

a plausible link between the practice and the impact.”). This is incorrect.

The district court is required to examine the merits of the underlying claim

in this context, only inasmuch as it must determine whether common questions exist; not to determine whether class members could actually prevail

on the merits of their claims. See Dukes v. Wal-Mart Stores, Inc., 603 F.3d

571, 592 (9th Cir. 2010) (en banc), reversed Wal-Mart, 131 S. Ct. 2541

(“[P]laintiffs and defendants disagree on whose statistical findings and

observations are more credible, but this disagreement is relevant only to

the merits of plaintiffs’ claim—whether plaintiffs actually suffered disparate treatment—and not to whether plaintiffs have asserted common questions of fact or law . . . .’ ” (citation omitted)); see also Wal-Mart, 131 S.

Ct. at 2552 n.6 (clarifying that Rule 23 does not authorize a preliminary

inquiry into the merits of the suit for purposes other than determining

whether certification was proper (citing Eisen, 417 U.S. at 177). To hold

otherwise would turn class certification into a mini-trial. 

17714 ELLIS v. COSTCO WHOLESALE CORP.
commonality and . . . that plaintiffs [had] not raised any significant challenges in this regard.” Ellis, 240 F.R.D. at 639.

The district court ultimately denied Costco’s challenge on this

point, however, stating that “Dr. Saad’s analysis has presented

an alternative approach but it has not discredited Dr. Drogin’s

results or methods [the evidence proffered by Plaintiffs].” Id.

Instead of examining the merits to decide this issue, it appears

the district court merely concluded that, because both Plaintiffs’ and Costco’s evidence was admissible, a finding of commonality was appropriate.

[10] The district court applied an impermissible legal

criteria, see Lozano, 504 F.3d at 725, and failed to resolve the

critical factual disputes centering around the national versus

regional nature of the alleged discrimination. Accordingly, we

vacate the district court’s finding of commonality and remand

for application of the appropriate legal standard. Because we

vacate and remand, rather than reverse, the district court’s

commonality determination, we also address the other Rule

23(a) factors.

B. Typicality

[11] To demonstrate typicality, Plaintiffs must show that

the named parties’ claims are typical of the class. Fed. R. Civ.

P. 23(a)(3). “The test of typicality ‘is whether other members

have the same or similar injury, whether the action is based

on conduct which is not unique to the named plaintiffs, and

whether other class members have been injured by the same

course of conduct.’ ” Hanon, 976 F.2d at 508 (citation omitted). “Typicality refers to the nature of the claim or defense

of the class representative, and not to the specific facts from

which it arose or the relief sought.” Id. (internal citation and

quotation marks omitted).

Costco argues that Plaintiffs cannot satisfy the typicality

requirement, because each of the named Plaintiffs’ respective

discrimination claims are subject to unique defenses. The disELLIS v. COSTCO WHOLESALE CORP. 17715
trict court, citing Hanon, rejected this argument and held that

“as a general matter, individualized defenses do not defeat

typicality.” Ellis, 240 F.R.D. at 641. 

[12] Hanon, however, supports Costco’s position. In

Hanon, we stated that “a named plaintiff ’s motion for class

certification should not be granted if ‘there is a danger that

absent class members will suffer if their representative is preoccupied with defenses unique to it.’ ” 976 F.2d at 508 (quoting Gary Plastic Packaging Corp. v. Merrill Lynch, Pierce,

Fenner & Smith, Inc., 903 F.2d 176, 180 (2d Cir. 1990)). We

found that the named plaintiff did not satisfy Rule 23(a)’s typicality requirement because his “unique background and factual situation require[d] him to prepare to meet defenses that

[were] not typical of the defenses which may be raised against

other members of the proposed class.” Id.

Costco asserts that it has unique defenses against each of

the named Plaintiffs. Specifically, as to Horstman, Costco’s

claimed defense is that, due to family reasons, Horstman

rejected rotation to Front End Manager and stated several

times that she wished to defer her pursuit of promotion for

three to five years. As to Ellis, Costco’s claimed defense is

that Ellis misrepresented her way into Costco, lacked the

Costco experience of other AGMs, transferred to a market

with limited promotional opportunities, and was disciplined

for abusing subordinates. As to Sasaki, Costco’s claimed

defense is that Sasaki is not an outstanding performer and that

Costco’s expert has concluded that there is no statistical evidence supporting a claim that females are promoted to GM at

a lesser rate in Sasaki’s region. 

[13] We decline to express an opinion, in the first instance,

about whether these defenses are typical of those that Costco

may raise against other members of the class or whether they

are unique such that Plaintiffs cannot satisfy Rule 23(a)’s typicality requirement.9

 Instead, we hold that the district court

9Costco also argues that Plaintiffs’ claims are not typical because experience as a Merchandise Manager is essential to promotion and, though

17716 ELLIS v. COSTCO WHOLESALE CORP.
misapplied Hanon, and thus abused its discretion by basing its

typicality determination on impermissible legal criteria. See

Lozano, 504 F.3d at 725. We vacate the district court’s typicality finding and remand so that the district court may apply

the appropriate legal standard.

C. Adequacy

[14] The named Plaintiffs must fairly and adequately protect the interests of the class. Fed. R. Civ. P. 23(a)(4). To

determine whether named plaintiffs will adequately represent

a class, courts must resolve two questions: “(1) do the named

plaintiffs and their counsel have any conflicts of interest with

other class members and (2) will the named plaintiffs and

their counsel prosecute the action vigorously on behalf of the

class?” Hanlon, 150 F.3d at 1020. Adequate representation

depends on, among other factors, an absence of antagonism

between representatives and absentees, and a sharing of interest between representatives and absentees. Molski v. Gleich,

318 F.3d 937, 955 (9th Cir. 2003), overruled on other

grounds by Dukes, 603 F.3d at 617.

Costco argues that the district court abused its discretion by

holding that the named Plaintiffs are adequate representatives.

Specifically, Costco argues that Ellis and Horstman have little

incentive to vigorously pursue injunctive relief on behalf of

some plaintiffs may lack such experience, the named Plaintiffs do not. We

reject this argument. Plaintiffs do not challenge whether Costco’s unofficial requirement that a person have experience as a Merchandise Manager

to be eligible for promotion is, by itself, a discriminatory promotion

requirement. Unique defenses aside, all three Plaintiffs allege that they

were not promoted because of their gender. Differing factual scenarios

resulting in a claim of the same nature as other class members does not

defeat typicality. Hanon, 976 F.2d at 508. Thus, the fact that the named

Plaintiffs had Merchandise Manager experience does not mean that Plaintiffs’ claims of gender discrimination are not typical of those of absent

class members, even though other class members may lack experience as

a Merchandise Manager. 

ELLIS v. COSTCO WHOLESALE CORP. 17717
the class, because they are former employees. Costco also

argues that Sasaki has little incentive to vigorously pursue

relief for those denied promotion to AGM, because she has

already reached the level of AGM.

[15] Sasaki is an adequate class representative. Costco’s

argument, that she does not have an incentive to vigorously

represent employees who have been denied a promotion to

AGM, misses the point of the litigation. The purported class

is composed of women who have been denied promotion to

either AGM or GM. The Costco policies and culture challenged by Plaintiffs apply equally to AGM and GM promotion decisions. Sasaki, although a current AGM, claims she

has been wrongly denied promotion to GM and thus shares an

interest with all class members. Nothing in the record suggests that Sasaki would not vigorously pursue injunctive relief

on behalf of the entire class. Thus, we hold that the district

court did not abuse its discretion by finding that Sasaki is an

adequate representative. 

[16] Whether Ellis and Horstman adequately represent the

class, however, depends entirely on how the district court

chooses to manage the class on remand. Currently, the certified class includes both current and former employees of

Costco. Ellis and Horstman, as former Costco employees,

would share an interest with many class members who are

former Costco employees. However, as we discuss infra,

Plaintiffs not employed by Costco throughout this case do not

have standing to seek injunctive relief. As former employees,

Ellis and Horstman would not share an interest with class

members whose primary goal is to obtain injunctive relief.

Thus, as the class currently stands, Ellis and Horstman will

not adequately protect the interests of the class as a whole. If,

however, the district court decides on remand to certify a

class of employees under Rule 23(b)(3), pursuant to our

instructions in Part III of this opinion, it will need to consider

in the first instance whether Ellis and Horstman can ade17718 ELLIS v. COSTCO WHOLESALE CORP.
quately represent the interests of the second class—i.e., those

seeking monetary damages. 

III. Rule 23(b)

[17] Turning to Rule 23(b), Costco argues that the district

court abused its discretion by certifying the class pursuant to

Rule 23(b)(2), because Plaintiffs do not primarily seek injunctive relief. Rule 23(b)(2) permits class actions for declaratory

or injunctive relief if “the party opposing the class has acted

or refused to act on grounds that apply generally to the class,

so that final injunctive relief or corresponding declaratory

relief is appropriate respecting the class as a whole . . . .” Id.

We agree that certification under Rule 23(b)(2) was improper,

although on another basis.

Relying primarily on our decision in Molski v. Gleich, 318

F.3d at 950, the district court examined the Plaintiffs’ subjective intent and held that injunctive relief was the predominant

form of relief sought. Ellis, 240 F.R.D. at 642-43. Specifically, the district court relied on declarations submitted by the

named Plaintiffs stating that their primary objective was

obtaining injunctive relief and noted that Costco had not

offered any alternative method of discerning Plaintiffs’ subjective intent in bringing the suit. Id. Having so concluded,

the district court easily found that Plaintiffs’ claims for compensatory and punitive damages were merely incidental to the

claim for injunctive relief. 

“Class certification under Rule 23(b)(2) is appropriate only

where the primary relief sought is declaratory or injunctive.”

Zinser, 253 F.3d at 1195. Although we have previously held

that in “Rule 23(b)(2) cases, monetary damage requests are

generally allowable only if they are merely incidental to the

litigation,” Kanter v. Warner-Lambert Co., 265 F.3d 853, 860

(9th Cir. 2001), this standard has been called into doubt by the

Supreme Court. Wal-Mart, 131 S. Ct. at 2560 (“We need not

decide in this case whether there are any forms of ‘incidental’

ELLIS v. COSTCO WHOLESALE CORP. 17719
monetary relief that are consistent with the interpretation of

Rule 23(b)(2) we have announced and that comply with the

Due Process Clause.”). 

The Supreme Court recently rejected the “predominance”

test for determining whether monetary damages may be

included in a 23(b)(2) class certification. Id. at 2559. Instead

of considering the amount of the damages sought or the subjective intent of the class members seeking relief to determine

if injunctive relief “predominates,” the relevant inquiry is

what procedural safeguards are required by the Due Process

Clause for the type of relief sought. Id. at 2557-58. 

The Advisory Committee, in amending the Rules to include

a (b)(3) class, noted that it was created for situations where

“class-action treatment is not as clearly called for.” Id. at 2558

(citation omitted). While expanding the breadth of possible

class actions, it also expanded the procedural protections

afforded the class. Id. Unlike classes certified under Rule

23(b)(1) or (b)(2), a (b)(3) class is not mandatory. Id. Instead,

putative class members are afforded the right to be notified of

the action and to opt out of the class. Id. (citing Rule

23(c)(2)(B)). The absence of these protections in a class

action predominantly for monetary damages violates due process. Phillips Petroleum Co. v. Shutts, 472 U.S. 797, 812

(1985). The Wal-Mart court later opined: “We fail to see why

the Rule should be read to nullify these protections whenever

a plaintiff class, at its option, combines its monetary claims

with a request—even a ‘predominating request’—for an

injunction.” 131 S. Ct. at 2559. 

[18] The Court relatedly held that “claims for individualized relief (like the backpay at issue here) do not satisfy [Rule

23(b)(2)],” noting that the “key to the (b)(2) class is the ‘indivisible nature of the injunctive or declaratory remedy warranted.’ ” Id. at 2557 (citation omitted). Rule 23(b)(2) “does not

authorize class certification when each class member would

be entitled to an individualized award of monetary damages.”

17720 ELLIS v. COSTCO WHOLESALE CORP.
Id. The district court erred, therefore, by focusing on evidence

of Plaintiffs’ subjective intent, instead of on whether the monetary relief could be granted absent “individualized determinations of each employee’s eligibility for [monetary

damages].” Id. at 2560. 

[19] We vacate the district court’s order finding that Plaintiffs had satisfied Rule 23(b)(2) and remand for the district

court to apply the legal standard established in Wal-Mart. On

remand, we highlight several factors for the district court to

consider. 

First, if the district court determines that a (b)(2) class may

be certified consistent with this opinion, it may consider

whether Plaintiffs’ claim for punitive damages may properly

be sought by a (b)(2) class.10 The district court earlier found

that claims for punitive damages are suitable for certification

under 23(b)(2), “because such . . . claim[s] focus[ ] on the

conduct of the defendant and not the individual characteristics

of the plaintiffs.” Ellis, 240 F.R.D. at 643; see also Dukes,

603 F.3d at 622 (noting that plaintiffs’ claim for punitive

damages did “not require individualized punitive damages

determinations”); Kolstad v. Am. Dental Assoc., 527 U.S. 526,

535 (1999) (noting that whether punitive damages are warranted is based on the employer’s state of mind, i.e., if “[t]he

employer [acted] with ‘malice or with reckless indifference to

the plaintiff ’s federally protected rights.’ ” (quoting 42

U.S.C. § 1981a(b)(1)) (emphasis and alterations omitted)).

The court may consider whether punitive damages are an

allowable “form[ ] of ‘incidental’ monetary relief” consistent

with the Court’s interpretation of 23(b)(2) because they do not

require an individual determination.” See Wal-Mart, 131 S.

Ct. at 2560. 

10In the alternative, if the district court certifies a (b)(3) class in place

of, or in addition to a (b)(2) class, it may determine that the punitive damages claim is more appropriate to a (b)(3) class. 

ELLIS v. COSTCO WHOLESALE CORP. 17721
Second, the district court must consider whether a class

may be certified under (b)(3) to address Plaintiffs’ compensatory damages and backpay claims. As the court properly recognized, compensatory damages require individual

determinations. Ellis, 240 F.R.D. at 643. We remand, therefore, for the district court to consider whether the class may

properly be certified under Rule 23(b)(3). The district court

must also consider whether the named Plaintiffs are adequate

representatives of the putative (b)(3) class.

Finally, if the district court determines that a class may be

certified, it must consider anew how to manage those members of the proposed class who are no longer Costco employees. As the Supreme Court explained, only current employees

have standing to seek injunctive relief. Wal-Mart, 131 S. Ct.

at 2559-60. Therefore, the district court must consider how

best to define the class(es) to ensure that all class members

have standing to seek the requested relief. See, e.g., Dukes,

603 F.3d at 620 (suggesting the court certify a “Rule 23(b)(2)

class for equitable relief and a separate Rule 23(b)(3) class for

damages”).

IV. Manageability

Finally, Costco argues that certification of the class would

either be unmanageable or violate its constitutional rights.

Although the district court declined to formally adopt a trial

plan at this stage, it did indicate that it could accommodate the

need for individualized determinations of compensatory damages by bifurcating the trial into different phases. Costco,

relying on International Brotherhood of Teamsters v. United

States, 431 U.S. 324 (1977), argues that such a plan is unmanageable and violates both its due process and Seventh Amendment rights.

Because the district court has not actually adopted a trial

plan yet and in light of our holding today to vacate the district

17722 ELLIS v. COSTCO WHOLESALE CORP.
court’s certification of the class under Rule 23, it is premature

for us to address these arguments now.

CONCLUSION

To summarize, we hold that at least one named Plaintiff

(Sasaki) has standing to bring suit. We hold that the district

court abused its discretion by applying the wrong legal standard in its analyses of commonality and typicality under Rule

23(a). Accordingly, we vacate the district court’s findings on

those issues and remand for application of the correct standard. Although we hold that the district court correctly determined that Sasaki is an adequate class representative, we hold

that Ellis and Horstman are inadequate representatives for

pursuing injunctive relief, given that they are former employees, and remand for the district court to consider whether they

are adequate representatives if a (b)(3) class is certified. We

vacate the district court’s certification of a class pursuant to

Rule 23(b)(2) and remand for reconsideration in light of this

opinion. 

AFFIRMED in part; VACATED in part; REMANDED.

Parties shall bear their own costs on appeal. 

ELLIS v. COSTCO WHOLESALE CORP. 17723