FOR PUBLICATION

UNITED STATES COURT OF APPEALS

FOR THE NINTH CIRCUIT

A. B. and A. M. B., by their parents 

and next friends, C.B. and D.B.; T. 

T., by her parents and next friends, 

K.T. and S.T.; A. P., by her parents 

and next friends, C.P. and M.P,

Plaintiffs-Appellants,

v.

HAWAII STATE DEPARTMENT OF 

EDUCATION; OAHU 

INTERSCHOLASTIC ASSOCIATION,

Defendants-Appellees.

No. 20-15570

D.C. No.

1:18-cv-00477-

LEK-RT

OPINION

Appeal from the United States District Court

for the District of Hawaii

Leslie E. Kobayashi, District Judge, Presiding

Argued and Submitted February 4, 2021

Honolulu, Hawaii

Filed April 4, 2022

Before: Richard R. Clifton, Ryan D. Nelson, and

Daniel P. Collins, Circuit Judges.

Opinion by Judge Collins
2 A. B. V. HAWAII STATE DEP’T OF EDUC.

SUMMARY*

Title IX / Class Certification

The panel reversed the district court’s order denying 

female student athletes’ motion for class certification in their 

action seeking declaratory and injunctive relief to redress 

alleged violations of Title IX in the athletic programs at a 

public high school in Hawaii.

Plaintiffs brought Title IX claims for failure to provide 

equal treatment and benefits, failure to provide male and 

female students with equivalent opportunities for 

participation in athletics, and retaliation against female 

athletes when issues of Title IX compliance were brought to 

the attention of high school administrators. The district court 

denied plaintiffs’ motion for class certification on the 

grounds that, under Fed. R. Civ. P. 23(a), they failed to meet 

the requirement of numerosity, and as to the retaliation 

claim, commonality and typicality were lacking. The district 

court concluded that because plaintiffs failed to meet one or 

more requirements of Rule 23(a), it was not necessary to 

address the additional requirements of Rule 23(b)(1)(B) and 

(b)(2).

As to numerosity, the panel held that Rule 23(a)(1) 

requires a party seeking class certification to show that “the 

class is so numerous that joinder of all members is 

impracticable.” The panel applied the standard set forth in 

Jordan v. County of Los Angeles, 669 F.2d 1311 (9th Cir. 

1982), vacated, 459 U.S. 810 (1982), on remand, 713 F.2d 

* This summary constitutes no part of the opinion of the court. It 

has been prepared by court staff for the convenience of the reader.
A. B. V. HAWAII STATE DEP’T OF EDUC. 3

503 (9th Cir. 1983), modified, 726 F.2d 1366 (9th Cir. 1984), 

which requires consideration of the size of the class as well 

as potentially countervailing factors including the 

geographical diversity of class members, the ability of 

individual claimants to institute separate suits, whether 

injunctive or declaratory relief is sought, and the ability to 

identify and locate class members. The panel concluded that 

the district court failed to give appropriate weight to the very 

large size of the proposed class, which well exceeded 300 

persons, and there were no countervailing case-specific 

considerations indicating that, despite the large class size, 

joinder of all class members was nonetheless practicable. 

The panel held that the district court also erred in failing 

adequately to consider the fact that the class, as defined, 

included “future” female student athletes at the high school. 

The panel therefore reversed the denial of class certification 

as to plaintiffs’ first and second claims and remanded with 

instructions to address whether plaintiffs also satisfied one 

or more of the criteria in Rule 23(b).

The panel held that as to plaintiffs’ third cause of action 

for unlawful retaliation, the district court erred in also 

denying class certification on the further ground that 

plaintiffs failed to show commonality and typicality because 

this claim was centered on the high school water polo team, 

rather than on female student athletes as a whole. The panel 

concluded that the district court failed adequately to consider 

plaintiffs’ contention that defendants’ alleged retaliatory 

actions had a classwide effect. In addition, the district court 

failed to properly consider the legal principles that govern a 

retaliation claim of this nature under Title IX and require 

consideration of whether plaintiffs fall within the zone of 

interests that Title IX protects.
4 A. B. V. HAWAII STATE DEP’T OF EDUC.

The panel held that the district court abused its discretion 

in concluding that plaintiffs did not meet the requirements of 

Rule 23(a). The panel therefore reversed the district court’s 

order denying class certification and remanded for it to 

consider whether plaintiffs satisfied Rule 23(b).

COUNSEL

Elizabeth Kristen (argued) and Kim Turner, Legal Aid at 

Work, San Francisco, California; Mateo Caballero and 

Jongwook Kim, ACLU of Hawaii Foundation, Honolulu, 

Hawaii; Harrison J. Frahn IV, Simpson Thacher & Bartlett 

LLP, Palo Alto, California; Jayma Marie Meyer, Simpson 

Thacher & Bartlett LLP, New York, New York; for 

Plaintiffs-Appellants.

Ewan C. Rayner (argued) and Kimberly T. Guidry, Deputy 

Attorneys General; Department of the Attorney General, 

Honolulu, Hawaii; for Defendant-Appellee Hawaii State 

Department of Education.

Lyle S. Hosoda and Addison D. Bonner, Hosoda and Bonner 

LLLC, Honolulu, Hawaii, for Defendant-Appellee Oahu 

Interscholastic Association.

Lee Brand, Roxane A. Polidora, and Athena G. Rutherford, 

Pillsbury Winthrop Shaw Pittman LLP, San Francisco, 

California, for Amici Curiae Civil Rights Organizations.
A. B. V. HAWAII STATE DEP’T OF EDUC. 5

OPINION

COLLINS, Circuit Judge:

Section 901(a) of Title IX of the Education Amendments 

of 1972 provides that, subject to certain exceptions, “[n]o 

person in the United States shall, on the basis of sex, be 

excluded from participation in, be denied the benefits of, or 

be subjected to discrimination under any education program 

or activity receiving Federal financial assistance.” 20 U.S.C. 

§ 1681(a). Although Title IX contains no express language 

creating a private cause of action, the Supreme Court has 

long held that the statute is enforceable through a judicially 

recognized implied private right of action. See Franklin v. 

Gwinnett Cnty. Pub. Schs., 503 U.S. 60, 65 (1992) (citing 

Cannon v. University of Chicago, 441 U.S. 677 (1979)). 

Invoking that right of action here, female student athletes at 

Hawaii’s largest public high school brought this putative 

class action seeking declaratory and injunctive relief to 

redress multiple alleged violations of Title IX, including 

systematic discriminatory deficiencies in their school’s 

athletic programs. The district court subsequently denied 

Plaintiffs’ motion for class certification, holding that 

Plaintiffs had failed to satisfy the requirements of Federal 

Rule of Civil Procedure 23(a). We authorized this 

interlocutory appeal under Rule 23(f), and we reverse.

I

A

Plaintiffs A.B., her younger sister A.M.B., T.T., and A.P. 

are or were female student athletes at James Campbell High 
6 A. B. V. HAWAII STATE DEP’T OF EDUC.

School (“Campbell”) in Ewa Beach on the island of Oahu.1 

At the time A.B. and T.T. moved for class certification in 

May 2019, all four were members of the Campbell girls’ 

varsity water polo team; A.B. and T.T. were also members 

of the girls’ varsity swimming team; and A.P. was also a 

member of the girls’ varsity soccer team.2 A.M.B. later 

stated that she also planned to join the swimming team. 

Plaintiffs allege that they and other female students at 

Campbell “experience grossly unequal treatment, benefits, 

and opportunities in relation to male athletes,” resulting in 

multiple violations of Title IX. As a result, A.B. and T.T. 

filed this suit in December 2018 against Defendant Hawaii 

State Department of Education (“the Department”), which is 

the agency that manages Campbell’s operations, and 

Defendant Oahu Interscholastic Association, which is an 

unincorporated entity that administers high school athletic 

programs for public high schools on Oahu. In the operative 

second amended complaint, Plaintiffs assert three separate 

causes of action available under Title IX and its 

implementing regulations: “(1) unequal treatment and 

benefits in athletic programs; (2) unequal participation 

opportunities in athletic programs; and (3) retaliation.” See 

1 A.B. and T.T. were seniors at the time this case was originally filed 

in late 2018 and graduated before the district court ruled on the class 

certification motion. A.P. was a senior at the time this case was argued 

and has presumably graduated. A.M.B. was a junior at the time of oral 

argument and is presumably a current senior. No party has suggested 

that this case is moot, and we perceive no basis for concluding that it is.

2 After the class certification motion was filed, but before the district 

court denied it, amended complaints were filed adding A.M.B. and A.P. 

as additional plaintiffs. All four Plaintiffs submitted declarations in 

support of the class certification motion.
A. B. V. HAWAII STATE DEP’T OF EDUC. 7

Ollier v. Sweetwater Union High Sch. Dist., 768 F.3d 843, 

851 (9th Cir. 2014).

In their first cause of action, Plaintiffs allege that

Defendants violated § 901(a) by failing to provide equal 

treatment and benefits. We have held that § 901(a)’s 

prohibition on discriminatory denial of educational benefits, 

as construed in the U.S. Department of Education’s 

implementing regulation governing school athletic 

programs, “require[s] equivalence in the availability, quality 

and kinds of . . . athletic benefits and opportunities provided 

[to] male and female athletes.” Mansourian v. Regents of 

Univ. of Cal., 602 F.3d 957, 964 (9th Cir. 2010) (internal 

quotation marks omitted) (citing 34 C.F.R. § 106.41(c)(2)–

(10)); see also 20 U.S.C. § 1682 (authorizing federal 

agencies extending federal financial assistance to issue 

appropriate “rules, regulations, or orders of general 

applicability”). Plaintiffs allege that Defendants violated 

this requirement by “failing to provide female student 

athletes from Campbell with treatment and benefits that are 

comparable to the treatment and benefits provided to male 

student athletes.”

In support of this claim, Plaintiffs allege, for example, 

that “male athletes at Campbell have exclusive access” to a 

very large “stand-alone athletic locker room facility that is 

located near the athletic fields,” while “female athletes at

Campbell have no standalone athletic locker room facility, 

whether located near the athletic fields or elsewhere on 

campus.” Plaintiffs allege that, as a result, “female athletes, 

including Plaintiffs, must carry their athletic gear around 

with them all day and have resorted to changing in teachers’ 

closets, in the bathroom of the nearest Burger King, and even 

on the practice field, potentially in full view of bystanders.” 

Plaintiffs also allege that, in contrast to Campbell’s well-
8 A. B. V. HAWAII STATE DEP’T OF EDUC.

equipped boys’ sports programs, the girls’ water polo and 

soccer programs have not been given adequate equipment, 

gear, and training facilities. Indeed, the complaint alleges 

that on multiple occasions, the girls’ water polo team lacked 

any access to a pool for practice, leaving them “no choice 

but to hold dry-land training sessions and open-ocean swim 

practices.” Plaintiffs also allege that coaches for the girls’ 

teams at Campbell are generally paid less than coaches for 

the boys’ teams, and that some assistant coaches for the 

girls’ teams are not paid at all.

Plaintiffs’ second cause of action alleges that Defendants

violated § 901(a) by failing to provide male and female 

students with equivalent opportunities for “participation” in 

athletics. See 20 U.S.C. § 1681(a). Relying again on the 

regulations implementing § 901(a)’s requirements, we have 

held that this obligation to provide equivalent participation 

opportunities requires consideration of “whether ‘the 

selection of sports and levels of competition effectively 

accommodate the interests and abilities of members of both 

sexes.’” Mansourian, 602 F.3d at 964 (quoting 34 C.F.R. 

§ 106.41(c)(1)). In addressing that question, our precedent 

applies a “three-part test,” under which a school has “three 

options” for satisfying this obligation: “(1) showing 

substantial proportionality (the number of women in 

[interscholastic] athletics is proportionate to their 

enrollment); (2) proving that the institution has a ‘history 

and continuing practice of program expansion’ for the 

underrepresented sex (in this case, women); or (3) where the 

[school] cannot satisfy either of the first two options, 

establishing that it nonetheless ‘fully and effectively 

accommodate[s]’ the interests of women.” Id. at 965 

(citation omitted); see also Ollier, 768 F.3d at 855 (applying 

this three-part test to high schools). Plaintiffs’ complaint 

alleges that Defendants’ management of athletics at 
A. B. V. HAWAII STATE DEP’T OF EDUC. 9

Campbell fails to satisfy any of these alternative prongs. In 

particular, Plaintiffs allege that there is 6.6% “participation 

gap” at Campbell between “female athletic participation” 

(which is 41.6% of the total number of athletic “roster 

spots”) and “female student body enrollment” (which is 

48.2% of the student body).

Plaintiffs’ third cause of action is asserted only against 

the Department and alleges that it violated § 901(a) by 

retaliating against female athletes at Campbell when A.B., 

T.T., and others brought issues of Title IX compliance to the 

attention of Campbell administrators. See Jackson v.

Birmingham Bd. of Educ., 544 U.S. 167, 178 (2005) (holding 

that “the text of Title IX prohibits a funding recipient from 

retaliating against a person who speaks out against sex 

discrimination, because such retaliation is intentional 

‘discrimination’ ‘on the basis of sex’”). Specifically, 

Plaintiffs allege that school administrators retaliated by 

threatening to cancel Campbell’s girls’ water polo program 

and by making the water polo team needlessly resubmit 

program paperwork. Plaintiffs further allege that these 

retaliatory actions created a “chilling effect among 

Campbell’s female athletes regarding identifying and 

complaining about other gender inequities in athletics” to the 

Department.

Plaintiffs’ complaint seeks only declaratory and 

injunctive relief against Defendants, as well as attorneys’ 

fees and costs under 42 U.S.C. § 1988.

B

Relying on Federal Rule of Civil Procedure 23(b)(1)(B) 

and (b)(2), Plaintiffs moved to certify a class of “all present 

and future Campbell female students and potential students 

who participate, seek to participate, and/or are or were 
10 A. B. V. HAWAII STATE DEP’T OF EDUC.

deterred from participating in athletics at Campbell.” After 

considering the evidence and arguments of both sides, the 

district court denied the motion.

The district court held that, as to all three claims, 

Plaintiffs had failed to make the required threshold showing 

that the class was “so numerous that joinder of all members 

is impracticable.” See FED. R. CIV. P. 23(a)(1). The court 

noted that the evidence supplied by Defendants indicated 

that “there were 366 Campbell female student-athletes in the 

2018–19 school year.” Nonetheless, because the “proposed 

class members are limited to the female student population 

from a single high school” and are thus “geographically tied 

to one area of Hawai`i, and identifiable through school and 

athletic records,” the court concluded that joinder of all class 

members was not impracticable. Although school records 

could not similarly identify future or potential female student 

athletes at Campbell, the district court held that those 

“subgroups” were irrelevant to the numerosity analysis 

because neither was “reasonably identifiable.”

Turning to the other elements of Rule 23(a), the district 

court held that Plaintiffs’ first and second causes of action—

which alleged denial of equal treatment and equal 

participation opportunities—raised several common 

questions of law or fact that were “capable of classwide 

resolution,” see Wal-Mart Stores, Inc. v. Dukes, 564 U.S. 

338, 350 (2011) (construing FED. R. CIV. P. 23(a)(2)), and 

that the individual Plaintiffs’ claims under these two causes 

of action were “typical” of the claims of the class. 

Specifically, Plaintiffs alleged a number of discrete 

discriminatory actions with inherently systemic effects on 

female student athletes, and the resulting “[u]nequal access, 

treatment, and benefits of athletic programs is a common 

injury among the named Plaintiffs and proposed class.”
A. B. V. HAWAII STATE DEP’T OF EDUC. 11

By contrast, the district court held that commonality and 

typicality were lacking with respect to Plaintiffs’ third cause 

of action, which alleges retaliation. Commonality was 

absent, the court concluded, because the retaliation claim 

arose from a dispute between “Campbell administrators[] 

and the water polo team and their parents,” and Plaintiffs had 

not “allege[d] any instances of retaliation against any 

athletes other than members of the water polo team.” For 

similar reasons, the district court concluded that the alleged 

retaliatory actions of the Department were “unique to the 

named Plaintiffs” and were therefore “not typical of the 

proposed class.”

Lastly, the district court found that Plaintiffs would be 

adequate representatives of the class, without distinguishing 

among the three claims.

Having concluded that Plaintiffs had failed to satisfy one 

or more requirements of Rule 23(a), the court stated that it 

was “not necessary to address” the additional requirements 

of Rule 23(b)(1)(B) and (b)(2).

Plaintiffs timely petitioned for leave to appeal pursuant 

to Federal Rule of Civil Procedure 23(f), and a panel of this 

court granted Plaintiffs’ petition. This court has jurisdiction 

over Plaintiffs’ appeal under 28 U.S.C. § 1292(e).

II

To obtain certification of a plaintiff class under Federal 

Rule of Civil Procedure 23, a plaintiff must satisfy both the 

four requirements of Rule 23(a)—“numerosity, 

commonality, typicality, and adequate representation”—and 

“one of the three requirements listed in Rule 23(b).” WalMart, 564 U.S. at 345, 349. These are not “mere pleading” 

requirements, and a plaintiff must “affirmatively 
12 A. B. V. HAWAII STATE DEP’T OF EDUC.

demonstrate . . . compliance with the Rule—that is, he [or 

she] must be prepared to prove that there are in fact

sufficiently numerous parties, common questions of law or 

fact, etc.” Id. at 350. Here, the district court never reached 

the issue of whether Plaintiffs had shown one of the elements 

of Rule 23(b),3 because it concluded that (1) Rule 23(a)’s 

required threshold showing of numerosity had not been 

made as to any of Plaintiffs’ claims; and (2) Rule 23(a)’s 

requirements of commonality and typicality had not been 

shown as to Plaintiffs’ retaliation claim. We review these 

determinations for abuse of discretion, keeping in mind that 

a “district court abuses its discretion where it commits an 

error of law, relies on an improper factor, omits a substantial 

factor, or engages in a clear error of judgment in weighing 

the correct mix of factors.” Senne v. Kansas City Royals 

Baseball Corp., 934 F.3d 918, 926 (9th Cir. 2019). Applying 

those standards, we reverse.

III

A

Rule 23(a)(1) requires a party seeking class certification 

to show that “the class is so numerous that joinder of all 

members is impracticable.” See FED. R. CIV. P. 23(a)(1). As 

the Supreme Court has explained, this “numerosity 

3 In moving for class certification, Plaintiffs argued that the requisite 

element of Rule 23(b) was satisfied either (1) because Defendants had 

“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,” see FED. R. CIV. P. 23(b)(2); 

or (2) because separate actions by individual class members could, “as a 

practical matter, . . . be dispositive of the interests of the other members” 

or could “substantially impair or impede [the other members’] ability to 

protect their interests,” see FED. R. CIV. P. 23(b)(1)(B).
A. B. V. HAWAII STATE DEP’T OF EDUC. 13

requirement requires examination of the specific facts of 

each case and imposes no absolute limitations.” General 

Tel. Co. of the NW., Inc. v. EEOC, 446 U.S. 318, 330 (1980). 

While thus eschewing any bright-line rules, the Court did go 

on to state that a class with only 15 members “would be too 

small to meet the numerosity requirement.” Id.

Plaintiffs contend that we should apply the standards for 

evaluating numerosity set forth in Jordan v. County of Los 

Angeles, 669 F.2d 1311 (9th Cir. 1982), vacated, 459 U.S. 

810 (1982), on remand, 713 F.2d 503 (9th Cir. 1983), 

modified, 726 F.2d 1366 (9th Cir. 1984). Defendants, 

however, contend that Jordan is no longer good law and in 

any event is distinguishable. Because the parties have 

pointed us to no other decision in which we have elaborated 

on the substantive standards for evaluating numerosity—and 

our own research has likewise revealed none—we begin by 

closely examining our decisions in Jordan.

In that case, the plaintiff’s class action complaint alleged 

that the defendant county’s consideration of “three types of 

criminal record, i.e., juvenile record, arrest record, and 

marijuana conviction record” constituted unlawful race 

discrimination against Blacks in violation of Title VII of the 

Civil Rights Act of 1964, 42 U.S.C. § 2000e et seq., as well 

as a violation of the Civil Rights Act of 1866, 42 U.S.C. 

§ 1981. See 669 F.2d at 1314–15. The district court denied 

plaintiff’s motion to certify separate classes as to each type 

of criminal record, concluding that all four requirements of 

Rule 23(a), including numerosity, had not been satisfied. Id. 

at 1318–23. We initially reversed, holding that all four 

requirements had been met. Id.

In addressing numerosity, Jordan indicated that a court 

must consider what the evidence shows concerning “the 

absolute number of class members.” 669 F.2d at 1319. 
14 A. B. V. HAWAII STATE DEP’T OF EDUC.

Although the size of the class “is not the sole determining 

factor,” we stated that, “where a class is large in numbers, 

joinder will usually be impracticable.” Id. By contrast, 

where the size of the class is more modest, “the number of 

class members does not weigh as heavily” in the analysis, 

and “other factors” bearing upon the feasibility and 

convenience of joinder may assume more significance. Id. 

These potentially countervailing factors include “the 

geographical diversity of class members, the ability of 

individual claimants to institute separate suits, and whether 

injunctive or declaratory relief is sought,” as well as the 

ability to identify and locate class members. Id. at 1319–20.

Applying these standards, we held that, “[a]lthough we 

would be inclined to find the numerosity requirement in the 

present case satisfied solely on the basis of the number of 

ascertained class members, i.e., 39, 64, and 71, we need not 

do so since the presence of other indicia of impracticability 

persuade us that the requirement has been met.” Id. at 1319. 

Specifically, we noted that “the relatively small size of each 

class member’s claim and the probability that the class 

members may be difficult to locate combine to make it 

impracticable for individual class members to join in the 

lawsuit.” Id. at 1319–20. We also observed that each class 

included “unnamed and unknown future black applicants” 

and that the “joinder of unknown individuals is inherently 

impracticable.” Id. at 1320. Based on these reasons, we held 

that “the district court erred in denying class certification for 

failure to satisfy the numerosity requirement.” Id.

We then proceeded to find that the plaintiff had also 

satisfied the commonality, typicality, and adequacy 

requirements of Rule 23(a). Id. at 1320–23. However, our 

analysis of the commonality and typicality factors expressly 

relied on the Fifth Circuit’s so-called “across-the-board” 
A. B. V. HAWAII STATE DEP’T OF EDUC. 15

rule, under which a plaintiff challenging one discriminatory 

practice was permitted to represent employees challenging 

different practices if all employees suffered similar injuries. 

Id. at 1320, 1322 (citing Johnson v. Georgia Hwy. Express, 

417 F.2d 1122, 1124 (5th Cir. 1969)). Shortly thereafter, the 

Supreme Court explicitly rejected that “across-the-board 

rule,” concluding that it improperly relied on a presumption 

that a discriminatory employment decision against the 

named plaintiff reflects a pervasive discriminatory policy 

that is then reflected in all of the defendant’s various hiring 

practices. See General Tel. Co. of the SW. v. Falcon,

457 U.S. 147, 157–58 (1982). The Court consequently 

vacated our decision in Jordan for reconsideration in light of 

Falcon. See Jordan, 459 U.S. at 810.

On remand, we concluded that, in light of the Supreme 

Court’s intervening abrogation of the across-the-board rule, 

as well as our “recomputation of the actual number of 

rejected black applicants,” the “numerosity requirement of 

Rule 23” had not been met. See Jordan, 726 F.2d at 1367 

(emphasis added), amending 713 F.2d at 504. In reaching 

that conclusion, however, we did not in any way suggest that 

our original decision’s substantive articulation of the 

numerosity standards was erroneous. Moreover, Falcon

does not address the standards for numerosity at all, and it 

therefore provides no basis for declining to follow our 

elaboration of the numerosity requirement in our initial 

decision in Jordan. See Miller v. Gammie, 335 F.3d 889, 

899–900 (9th Cir. 2003) (en banc). Accordingly, we will 

apply Jordan’s framework in assessing numerosity here.

B

We conclude that the district court’s numerosity analysis 

was inconsistent with Jordan in two respects.
16 A. B. V. HAWAII STATE DEP’T OF EDUC.

1

First, the district court failed to give appropriate weight 

to the very large size of the proposed class. Plaintiffs 

presented uncontroverted evidence that in the 2016–2017, 

2017–2018, and 2018–2019 school years, the annual number 

of female student athletes at Campbell ranged between 366 

and 434. Thus, even considering only currently enrolled 

students, the evidence amply shows that a reasonable 

estimate of the size of the class well exceeds 300 persons.

Defendants contend that Plaintiffs failed to make any 

showing that all current female student athletes have been 

subjected to the alleged Title IX violations and are therefore 

class members, but we think this argument overlooks both 

the substance of Plaintiffs’ claims and the applicable 

standards for liability under Title IX. Some aspects of 

Plaintiffs’ first cause of action, which alleges unequal 

treatment and benefits, explicitly rest on allegations of 

systemic discrimination (such as, for example, the complete 

lack of standalone athletic locker facilities) that, if proved, 

would necessarily apply to all current female student 

athletes. See supra at 7–8. As to the second cause of action 

for unequal participation opportunities, the three-part test we 

apply for evaluating such claims is framed in terms that 

examine the school’s overall treatment of female athletic 

programs versus male athletic programs. See supra at 8. 

And for reasons we explain further below, we conclude that 

Plaintiffs’ third cause of action for retaliation likewise 

properly rests upon asserted classwide adverse impacts on 

female student athletes at Campbell. See infra at 24–26. It 

follows that Plaintiffs amply showed that the absolute 

number of class members as to each claim is well over 300 

persons. The resulting class size qualifies as “large in 

numbers” by any metric, and therefore, under Jordan, that 
A. B. V. HAWAII STATE DEP’T OF EDUC. 17

large class size weighs in favor of concluding that joinder of 

all of these persons is impracticable. 669 F.2d at 1319.

On this record, we find no countervailing case-specific 

considerations indicating that, despite the large class size, 

joinder of all class members is nonetheless practicable. In 

concluding that joinder of all class members was practicable 

here, despite the potential size of the class, the district court 

emphasized that all of Campbell’s current female student 

athletes could be identified “through school and athletic 

records” and that all of them were local and within the 

jurisdiction of the court. But the standard under Rule 23(a) 

is not, as the district court seemed to think, whether joinder 

is a literal impossibility. Rather, the question is whether 

joinder of all class members is “practicable”—i.e., 

“reasonably capable of being accomplished.” See

Practicable, BLACK’S LAW DICTIONARY (11th ed. 2019) 

(emphasis added); see also Harris v. Palm Springs Alpine 

Ests., Inc., 329 F.2d 909, 913–14 (9th Cir. 1964) 

(“‘[I]mpracticability’ does not mean ‘impossibility,’ but 

only the difficulty or inconvenience of joining all members 

of the class.”); Robidoux v. Celani, 987 F.2d 931, 935 (2d 

Cir. 1993) (“Impracticable does not mean impossible.”).

Here, joinder of all class members is not “reasonably 

capable of being accomplished” because it would impose 

very substantial logistical burdens for little, if any, benefit. 

Where, as here, the class seeks only prospective injunctive 

and declaratory relief, the practical value of joining each of 

the 300+ class members as a formal party is slim to nonexistent and is plainly outweighed by the substantial 

logistical burdens that would entail. See Jordan, 669 F.2d 

at 1319 (noting that “whether injunctive or declaratory relief 

is sought” is relevant to assessing whether joinder of class 

members is impracticable); see also Harris, 329 F.2d at 913 
18 A. B. V. HAWAII STATE DEP’T OF EDUC.

(stating that, in assessing impracticability, the court should 

consider “the expense and burden[] to the parties and the 

court”).

2

Second, the district court also failed adequately to 

consider the fact that the class, as defined, included “future” 

Campbell female student athletes.

“The inclusion of future class members in a class is not 

itself unusual or objectionable,” because “[w]hen the future 

persons referenced become members of the class, their 

claims will necessarily be ripe.” Rodriguez v. Hayes, 

591 F.3d 1105, 1118 (9th Cir. 2010). We have recognized 

that when, as here, a class’s membership changes continually 

over time, that factor weighs in favor of concluding that 

joinder of all members is impracticable. See Jordan, 

669 F.2d at 13204; see also J.D. v. Azar, 925 F.3d 1291, 1322 

4 Plaintiffs construe Jordan as standing for the broader proposition 

that any proposed class that includes future members automatically

satisfies the numerosity requirement, because future members are 

inherently unidentifiable at the time of class certification and thereby 

cannot practicably be joined. We do not read Jordan as establishing such 

a sweeping proposition. As an initial matter, Jordan’s assumption that 

the plaintiff in that case could represent all “future” class members 

appears to have rested in part on its application of the Fifth Circuit’s 

“across-the-board” rule. See 669 F.2d at 1320 (citing Jack v. American

Linen Supply Co., 498 F.2d 122 (5th Cir. 1974)). That aspect of the 

decision therefore did not survive Falcon, which would also explain why 

we did not mention future class members in our decision on remand in 

Jordan. See 713 F.2d at 504, as amended, 726 F.2d at 1366–67. 

Moreover, as we explicitly recognized in Rodriguez, the inclusion of 

future class members in a class definition is subject to the ripeness 

requirement of Article III, see 591 F.3d at 1118, and so the relevant 

numerosity inquiry concerning future class members is whether it would 

be practicable to join such future members as their claims become ripe.
A. B. V. HAWAII STATE DEP’T OF EDUC. 19

(D.C. Cir. 2019) (noting that this factor weighs in favor of 

impracticability of joinder even if current class members are 

relatively fewer in number); cf. Smith v. Swormstedt, 57 U.S. 

288, 303 (1854) (indicating, in a pre-Rules equitable suit 

brought by members and preachers of one branch of a church 

against those in the other branch, that joinder of all members 

would be impracticable due to the large and changing 

membership of the churches); see generally 7A CHARLES 

ALAN WRIGHT, ARTHUR R. MILLER, & MARY KAY KANE, 

FEDERAL PRACTICE AND PROCEDURE § 1762 at 227–29 (4th 

ed. 2021).

The district court declined to consider this factor because 

it concluded that future class members were not “reasonably 

identifiable,” and the court therefore could not make a 

“reasonable approximation” of the number of such members. 

This reasoning misconstrues the significance of this factor. 

The fact that it may not be possible to identify future class 

members at the time of class certification does not mean that 

this factor therefore drops out of the analysis and may be set 

aside. On the contrary, as we held in Jordan, the fact that 

the membership of a class changes over time makes joinder 

of every class member all the more impracticable. See

669 F.2d at 1320. This case well illustrates the point. Every 

year, as new freshmen matriculate into Campbell and as 

seniors graduate, the membership of potentially 25% of the 

student body may be expected to turn over. Given the purely 

equitable nature of the claims, there is little if any benefit to 

continually joining, or potentially dismissing, large numbers 

of additional class members. That makes the 

impracticability analysis all the more lopsided in favor of 

finding numerosity.

For similar reasons, the district court abused its 

discretion in concluding that a “reasonable approximation” 
20 A. B. V. HAWAII STATE DEP’T OF EDUC.

of future class members could not be made in this case. 

Given the three years of data in the record concerning the 

approximate number of current class members for each 

school year from 2016–2019, it is not difficult to reasonably 

estimate the extent to which class membership might be 

expected to change each year. For present purposes, all that 

is needed is a sufficient estimate of the number of future 

class members to allow the court to assess what weight to 

give to this factor when considered together with the other 

pertinent considerations. Here, as we have explained, the 

estimate of the current membership is well over 300 persons 

and already weighs heavily in favor of finding numerosity. 

The fact that additional persons, totaling as many as 25% of 

that number, would also need to be formally joined each year 

tips the balance even more strongly in favor of concluding 

that the “class is so numerous that joinder of all members is 

impracticable.” See FED. R. CIV. P. 23(a)(1).5

C

We therefore conclude that the district court erred in 

holding that Plaintiffs had not satisfied the numerosity 

requirement of Rule 23(a). And because that was the sole 

ground on which the court concluded that the requirements 

of Rule 23(a) had not been met as to Plaintiffs’ first and 

second causes of action, we reverse the denial of class 

certification as to those claims and remand with instructions 

to address whether Plaintiffs also satisfied one or more of the 

criteria in Rule 23(b).

5 In view of this analysis, we find it unnecessary to address the 

parties’ arguments as to whether numerosity is further established by the 

presence, in the class definition, of female student non-athletes who were 

deterred from participation in sports by Defendants’ alleged Title IX 

violations.
A. B. V. HAWAII STATE DEP’T OF EDUC. 21

IV

As to Plaintiffs’ third cause of action for unlawful 

retaliation, the district court also denied class certification on 

the further ground that Plaintiffs had failed to show 

commonality and typicality. This conclusion was also 

flawed.

The commonality requirement of Rule 23(a)(2) requires 

plaintiffs seeking class certification to show that their claims 

“depend upon a common contention” that “is capable of 

classwide resolution—which means that determination of its 

truth or falsity will resolve an issue that is central to the 

validity of each one of the claims in one stroke.” Wal-Mart, 

564 U.S. at 350. To establish typicality, as required by Rule 

23(a)(3), plaintiffs must show that “the claims or defenses of 

the representative parties are typical of the claims or 

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

1992) (citation omitted). Because the considerations 

underlying the two requirements overlap considerably, the 

Supreme Court has noted that “[t]he commonality and 

typicality requirements of Rule 23(a) tend to merge.” 

Falcon, 457 U.S. at 157 n.13.

The district court concluded that these two requirements 

were not satisfied here, because in its view Plaintiffs’ 

retaliation claim is centered on the water polo team rather 

than on female student athletes as a whole. As the district 

court explained, the Department’s retaliatory actions arose 

from “a dispute between Defendants, specifically limited to 

Campbell administrators, and the water polo team and their 
22 A. B. V. HAWAII STATE DEP’T OF EDUC.

parents,” and the only claimed instances of actual retaliation 

were against “members of the water polo team.” This 

reasoning misapprehends Plaintiffs’ retaliation claim and the 

law governing it.

Although the Department’s alleged retaliatory actions 

were immediately directed at the water polo team, whose 

members and their parents had made complaints about 

unequal treatment, the district court failed adequately to 

consider Plaintiffs’ contention that those actions had a 

classwide effect. Specifically, Plaintiffs assert that the 

example that the Department made of the girls’ water polo 

team had the effect of broadly dissuading Campbell’s female 

student athletes from “raising the issue of sex 

discrimination” out of fear that the Department would 

likewise retaliate against them. Indeed, a declaration 

submitted by one of the Plaintiffs’ parents specifically 

averred that other students and parents had “expressed 

interest in joining the lawsuit, but were scared about the 

repercussions from [the Department] if they did so.” This 

parent explained that, for example, one student who was a 

“star athlete” and who hoped to win college scholarships, 

was too afraid “to jeopardize her relationship with the 

school.”

In addition to overlooking the broader theory of unlawful 

retaliation that Plaintiffs raised here, the district court failed 

to properly consider the legal principles that govern a 

retaliation claim of this nature under Title IX. On this point, 

we find our prior decision in Ollier to be instructive, and so 

we address that decision in some detail.

In Ollier, complaints concerning a high school’s 

compliance with Title IX were made by the named plaintiffs’ 

parents and the girls’ softball coach, Chris Martinez. 

768 F.3d at 853, 866–67. In response, the school fired 
A. B. V. HAWAII STATE DEP’T OF EDUC. 23

Coach Martinez and replaced him with a “far less 

experienced coach,” eliminated the girls’ softball team’s 

assistant coaches, and took a variety of other actions that 

“disrupted” the girls’ softball program. Id. at 869. On 

appeal, the defendants made a series of arguments that 

resemble those made by the Department here. Specifically, 

the Ollier defendants argued that the named plaintiffs 

“lack[ed] standing to enjoin the retaliatory action allegedly 

taken against Coach Martinez”; that they also “lack[ed] 

standing because it was not they who made the Title IX 

complaints”; and that classwide relief was unwarranted 

because “only some members of the plaintiff[s’] class . . . 

can urge they engaged in protected activity.” Id. at 865–66, 

868. We rejected all of these contentions, concluding that 

they rested on too restrictive a view of Title IX’s cause of 

action for retaliation. Id. at 866–69.

We held that the named plaintiffs clearly asserted a 

sufficient injury-in-fact to satisfy Article III, because their 

“prospects for competing were hampered” when the 

defendants “impermissibly retaliated against them by firing 

Coach Martinez.” Id. at 865 (emphasis in original). We also 

recognized, however, that what the defendants characterized 

as “standing” arguments actually rested primarily on the 

general prudential rule against asserting the rights of third 

parties. Id. (citing Warth v. Seldin, 422 U.S. 490, 499 

(1975)); cf. Lexmark Int’l, Inc. v. Static Control 

Components, Inc., 572 U.S. 118, 126 (2014) (noting that “the 

general prohibition on a litigant’s raising another person’s 

legal rights” is “not derived from Article III,” but reflects 

what has inexactly been called the “‘prudential’ branch of 

standing”). Addressing the question that way, we held that 

the named plaintiffs could assert a Title IX retaliation claim 

based on retaliatory actions that were directed at another 

person (Coach Martinez) and that were triggered by 
24 A. B. V. HAWAII STATE DEP’T OF EDUC.

complaints made by others (Coach Martinez and various 

parents). Ollier, 768 F.3d at 866–67.

In reaching that conclusion, we noted that the Supreme 

Court had addressed a somewhat similar individual thirdparty retaliation claim under Title VII in Thompson v. North 

American Stainless, LP, 562 U.S. 170, 177–78 (2011). See 

Ollier, 768 F.3d at 866. There, both Thompson and his 

fiancée worked in the same company, and the allegation was 

that Thompson was fired in retaliation for complaints about 

sex discrimination made by his fiancée. Thompson, 562 U.S. 

at 172. The Court held that, because Thompson was within 

the “zone of interests” protected by Title VII, he had a cause 

of action for retaliation even though his fiancée was the one 

who had engaged in the protected activity that led to the 

retaliation. Id. at 177–78. We concluded in Ollier that this 

same zone-of-interest analysis applies to Title IX, and we 

therefore considered whether the named plaintiffs in that 

case were “within the ‘zone of interests’ that Title IX’s 

implicit antiretaliation provisions seek to protect.” Ollier, 

768 F.3d at 866; see also Lexmark, 572 U.S. at 127 & n.3 

(suggesting that, in many cases, “third-party standing” is 

really an issue of whether the party has a cause of action 

under a statute, which in turn depends in part on the zone-ofinterests test). Because those named plaintiffs were students 

who had suffered a diminished athletic experience due to 

retaliation, we concluded that they easily fell within Title 

IX’s zone of interests. Ollier, 768 F.3d at 866. They 

therefore had a cause of action under Title IX to seek redress 

for those injuries, despite the fact that the actual Title IX 

complaints that led to the retaliation were “made by their 

parents and Coach Martinez.” Id. at 866–67.

We similarly held that classwide injunctive relief was

properly awarded in Ollier, despite the fact that many of the 
A. B. V. HAWAII STATE DEP’T OF EDUC. 25

class members had not even been “members of the softball 

team at the time of retaliation.” Id. at 868. In so holding, we 

reiterated the breadth of Title IX’s zone of interests, see id. 

(citing Thompson, 562 U.S. at 178), and asserted that we had 

approved similarly broadly-defined classes that included “all 

current and future” female students, id. (citation omitted). 

Because the class members in Ollier had been affected by 

the retaliation and were within the zone of interests protected 

by Title IX’s prohibition on retaliation, the district court 

properly extended its grant of injunctive relief “so as to 

vindicate the rights of former and future students.” Id.

Although Ollier did not directly address the issue of class 

certification, see id. at 854 n.4, it is clear that the district 

court’s application of Rule 23(a)’s requirements to 

Plaintiffs’ retaliation claim in this case cannot be reconciled 

with Ollier’s analysis of the law governing such claims. 

Here, as in Ollier, the specific Title IX complaints that led to 

the retaliation were made only by a particular subset of 

people (here, particular students and parents associated with 

the water polo team). But the concerns those persons raised 

swept more broadly to include Campbell’s treatment of girls’ 

athletics generally, and Plaintiffs have likewise presented 

evidence that the resulting retaliation had a deterrent effect 

on female students more generally. See supra at 22. Thus, 

under Ollier’s reasoning, those other putative class 

members—even those not on the water polo team—would 

fall within Title IX’s zone of interests and would have a 

cause of action for equitable relief against the Department’s 

retaliatory actions. See 768 F.3d at 866–67. And, as in 

Ollier, the fact that many of the class members were not the 

direct targets of the alleged retaliation would not necessarily 

be a bar to classwide relief. Id. at 868.
26 A. B. V. HAWAII STATE DEP’T OF EDUC.

It follows from these conclusions that the district court 

abused its discretion in holding that Plaintiffs had not 

established commonality and typicality as to their retaliation 

claim. Given that the retaliation claims of both the named 

Plaintiffs and the class members would rest on the 

underlying motivation for the Department’s alleged 

retaliatory actions in response to receiving Title IX 

complaints, that issue of retaliatory motive raises a common 

question whose answer will “resolve an issue that is central 

to the validity of each one of the claims in one stroke.” WalMart, 564 U.S. at 350. That is sufficient to satisfy Rule 

23(a)(2).

For similar reasons, the district court erred in concluding, 

in effect, that the direct victims of unlawful retaliation have 

claims that are atypical of the claims of the indirect victims. 

Plaintiffs’ retaliation claim is not premised solely on the 

injury of threatening to cancel Campbell’s girls’ water polo 

program and make the water polo team needlessly resubmit 

program paperwork. Instead, it is also premised on the 

“chilling effect” felt by female athletes throughout the high 

school. And where, as claimed here, the persons who raised 

broader concerns about Title IX compliance were met with 

a retaliatory response that likewise impacted female student 

athletes generally, the indirect victims’ claims depend

critically upon the success of the direct victims’ claims. As 

a result, there is little prospect that the named plaintiffs’ 

claims could be said to be burdened with defenses or issues 

unique to them and distinct from the other class members. 

See Hanon, 976 F.2d at 508. Plaintiffs thus established 

typicality under Rule 23(a)(3).

* * *

For the foregoing reasons, the district court abused its 

discretion in concluding that Plaintiffs had not met the 
A. B. V. HAWAII STATE DEP’T OF EDUC. 27

requirements of Rule 23(a). We reverse the district court’s 

order denying class certification and remand for it to 

consider whether Plaintiffs satisfied Rule 23(b).

REVERSED AND REMANDED.