                               In the

    United States Court of Appeals
                 For the Seventh Circuit
                     ____________________
No. 19-1831
CHRISTINE DANCEL,
                                                  Plaintiﬀ-Appellant,
                                 v.

GROUPON, INC.,
                                                 Defendant-Appellee.
                     ____________________

         Appeal from the United States District Court for the
           Northern District of Illinois, Eastern Division.
          No. 1:18-cv-02027 — Ronald A. Guzmán, Judge.
                     ____________________

 ARGUED SEPTEMBER 16, 2019 — DECIDED DECEMBER 18, 2019
                ____________________

   Before BAUER, BRENNAN, and ST. EVE, Circuit Judges.
    ST. EVE, Circuit Judge. Is a person’s username a part of her
identity? That is a complex question, but one that Christine
Dancel proposes can be resolved categorically for all
usernames and all people. The district court thought other-
wise and declined to certify a class because it would have to
be decided username-by-username whether each one is an as-
pect of a given class member’s identity, at least as that word
is deﬁned by the Illinois Right of Publicity Act (IRPA), 765
2                                                  No. 19-1831

ILCS 1075/5. Dancel contends this rejection of her theory was
an improper decision on the merits of her and the class’s
claims, and the court therefore abused its discretion at the
class-certiﬁcation stage. We see no such mistake in the district
court’s reasoning and aﬃrm the order denying certiﬁcation.
                        I. Background
    Groupon, Inc. is an online marketplace that sells vouchers
for other businesses. Groupon’s website gives each business
its own page with information about the business and the dis-
counts available. Between April 2015 and February 2016,
some visitors to the site could scroll down each page to see a
“Photos” section that displayed up to nine pictures. If the vis-
itor clicked a button, the page would reveal up to eighteen
more. Groupon collected and displayed these pictures auto-
matically using what it calls the “Instagram Widget.” As its
name suggests, this Widget pulled publicly available pictures
from the social networking service Instagram. It selected
which pictures to assign to each page based on data linking
the photos to the advertised business’s location. When a
Groupon visitor hovered her cursor over a displayed photo,
the Widget would show the unique, user-selected username
of the Instagram account whose photo was being displayed
and a caption, if the user had attached one to the photo.
     Dancel is an Instagram user, and like all Instagram users,
her account had a username—namely, “meowchristine.” In
2015, Dancel uploaded to her account a picture of herself and
her boyfriend visiting Philly G’s, a restaurant in Vernon Hills,
Illinois. This picture was one of several Groupon displayed on
Philly G’s page while the Widget was active.
No. 19-1831                                                    3

    Dancel alleges that Groupon’s inclusion of her photo and
username on Philly G’s page violated the IRPA, which pro-
hibits the use of a person’s identity—meaning an “attribute of
an individual that serves to identify that individual to an or-
dinary, reasonable viewer or listener”—for commercial pur-
poses without consent. 765 ILCS 1075/5, 30. She ﬁled suit in
the Circuit Court of Cook County and sought to maintain the
action on behalf of a class of “Illinois residents” whose photo-
graphs Groupon had similarly shown on its pages. The par-
ties litigated in that posture for two years until Dancel moved
to certify a diﬀerent class, deﬁned as “[a]ll persons who main-
tained an Instagram Account and whose photograph (or pho-
tographs) from such account was (or were) acquired and used
on a groupon.com webpage for an Illinois business.” The class
also had a sub-class: “All members of the Instagram Class
whose likeness appeared in any photograph acquired and
used by Groupon.”
    In response to these new class deﬁnitions, Groupon re-
moved the case to federal court. Dancel tried to argue this re-
moval came too late, but the district court disagreed, denied
her motion to remand to state court, and proceeded to decide
whether to certify her proposed class under Federal Rule of
Civil Procedure 23(b)(3). That provision requires, among
other things, “that the questions of law or fact common to
class members predominate over any questions aﬀecting only
individual members.” Dancel identiﬁed the common ques-
tion that united the class as “whether Instagram usernames
categorically fall within the statutory deﬁnition of ‘identity.’”
She distinguished this inquiry from the individualized ques-
tion “whether any particular username identiﬁes an individ-
ual.”
4                                                   No. 19-1831

    The district court found Dancel’s categorical theory “un-
persuasive.” Though the court accepted that a common ques-
tion existed as to whether any username identiﬁes an individ-
ual, that question was not enough to certify a class because it
“ignore[d] the individual inquiry that is the essence of deter-
mining ‘identity’ under the IRPA.” The district court listed
several of the usernames belonging to class members—e.g.,
eawhalen, artistbarbie, isa.tdg, loparse, johanneus—and con-
cluded that it was “simply impossible to make any type of
across-the-board determination as to whether these names
‘identify’ a particular person, as that term is deﬁned by the
IRPA.” Because it determined that the IRPA, as applied to the
facts of this case, required a “username-by-username (photo-
by-photo)” inquiry, the court found that common questions
would not predominate over individual ones and denied cer-
tiﬁcation. Dancel petitioned for review of that decision, and
we granted the petition. Fed. R. Civ. P. 23(f).
                        II. Jurisdiction
    We start our analysis where we left oﬀ after our previous
opinion: the district court’s jurisdiction. Dancel v. Groupon,
Inc., 940 F.3d 381, 386 (7th Cir. 2019). The Class Action Fair-
ness Act, 28 U.S.C. § 1332(d)(2), extends federal subject-matter
jurisdiction to a proposed class action that is, among other
things, minimally diverse—meaning one member of the
plaintiﬀ class is a citizen of a state diﬀerent from any one de-
fendant. Groupon is a Delaware corporation with its principal
place of business in Illinois; it is therefore a citizen of those
two states. Instead of alleging the citizenship of even one di-
verse class member, Groupon asserted only that the class “un-
doubtedly would include at least some undetermined num-
ber of non-Illinois and non-Delaware citizens as class
No. 19-1831                                                     5

plaintiﬀs.” We agreed with Dancel that this allegation failed
to carry Groupon’s burden and directed Groupon to amend
its notice of removal. Dancel, 940 F.3d at 384–85. Though 28
U.S.C. § 1653 permits a party to amend jurisdictional allega-
tions on appeal, see Heinen v. Northrop Grumman Corp., 671
F.3d 669, 670 (7th Cir. 2012), Groupon said it required discov-
ery to make those amendments, so we ordered a limited re-
mand for the district court to oversee that discovery and con-
ﬁrm its jurisdiction. Dancel, 940 F.3d at 386.
    On remand, Groupon amended its allegations and supple-
mented its notice of removal with three aﬃdavits in which the
aﬃants attested to their signiﬁcant ties to their home states,
which are not Illinois or Delaware. Groupon also provided the
incorporation and registration documents for two Instagram-
using businesses based in California and Missouri. Dancel ar-
gued that these businesses and one of the aﬃants fell outside
the class deﬁnition, but she conceded that the other two aﬃ-
davits belonged to putative class members domiciled in Vir-
ginia and California, respectively. See Myrick v. WellPoint, Inc.,
764 F.3d 662, 664 (7th Cir. 2014) (“Citizenship means domicile
(the person’s long-term plan for a state of habitation) rather
than just current residence.”). The district court saw no reason
to conduct an evidentiary hearing to peer beyond Groupon’s
allegations and Dancel’s concession (which was well sup-
ported by Groupon’s evidence anyway), and neither do we.
See Tilden v. Comm'r, 846 F.3d 882, 887 (7th Cir. 2017) (explain-
ing that parties can agree to the fact of the parties’ citizen-
ship—as distinct from the existence of jurisdiction—if the
agreement is not collusive). With these amended allegations
that at least one class member was a citizen of Virginia and
another of California, Groupon has shown minimal diversity
between it and the proposed class, and the district court’s
6                                                     No. 19-1831

exercise of jurisdiction was proper. We may now move on to
the class-certiﬁcation decision.
                     III. Class Certiﬁcation
    Dancel argues that the district court improperly addressed
the merits of her IRPA claim at the class-certiﬁcation stage,
and that, to the extent those merits are not oﬀ limits, the court
resolved them incorrectly. She posits that the individual con-
tent of each username is irrelevant to the class’s claims. In her
view, an Instagram username is inherently an identity under
the IRPA because it is unique—no two accounts can use the
same username at the same time. Because this theory ignores
the usernames’ content, Dancel maintains it cannot depend
on the individual usernames of the class members but only on
the common evidence describing the general function of In-
stagram usernames and the Instagram Widget. She primarily
insists that she is entitled to test her theory, regardless of its
validity, on a class-wide basis because Rule 23 prohibits a
court from resolving the merits of a claim at the class-certiﬁ-
cation stage. To the extent that the court can consider the va-
lidity of her theory, she contends the district court imposed a
higher evidentiary burden than the IRPA requires.
    We review the district court’s certiﬁcation decision for an
abuse of discretion, but a district court necessarily abuses its
discretion if its reasoning is based on a legal error, like those
Dancel asserts. See Beaton v. SpeedyPC Software, 907 F.3d 1018,
1025 (7th Cir. 2018), cert. denied, 139 S. Ct. 1465 (2019). We con-
clude that the district court did not legally err in its interpre-
tation of the Federal Rules of Civil Procedure or the IRPA and
did not otherwise abuse its discretion.
No. 19-1831                                                      7

A. Rule 23(b)(3)
    A plaintiﬀ seeking class certiﬁcation bears the burden of
proving that her proposed class meets the four requirements
of Federal Rule of Civil Procedure 23(a), as well as those for
one of the three types of classes identiﬁed in Rule 23(b). Bea-
ton, 907 F.3d at 1025. We, like the district court, need not reach
the Rule 23(a) elements, because we agree that Dancel has
failed to meet those of Rule 23(b)(3)—the provision on which
she relies. See Riﬀey v. Rauner, 910 F.3d 314, 318 (7th Cir. 2018),
cert. denied sub nom. Riﬀey v. Pritzker, 139 S. Ct. 2745 (2019).
   Federal Rule of Civil Procedure 23(b)(3) requires a district
court to ﬁnd that “the questions of law or fact common to class
members predominate over any questions aﬀecting only indi-
vidual members.” This distinction is often easier stated than
applied:
   An individual question is one where “members of a
   proposed class will need to present evidence that var-
   ies from member to member,” while a common ques-
   tion is one where “the same evidence will suﬃce for
   each member to make a prima facie showing [or] the
   issue is susceptible to generalized, class-wide proof.”
Tyson Foods, Inc. v. Bouaphakeo, 136 S. Ct. 1036, 1045 (2016) (al-
teration in original) (quoting 2 W. Rubenstein, Newberg on
Class Actions § 4:50 (5th ed. 2012)); Messner v. Northshore Univ.
HealthSystem, 669 F.3d 802, 815 (7th Cir. 2012) (“If, to make a
prima facie showing on a given question, the members of a
proposed class will need to present evidence that varies from
member to member, then it is an individual question. If the
same evidence will suﬃce for each member to make a prima
facie showing, then it becomes a common question.” (quoting
8                                                    No. 19-1831

Blades v. Monsanto Co., 400 F.3d 562, 566 (8th Cir. 2005))). One
way of establishing that common evidence can supply an an-
swer to a common question is to consider whether an individ-
ual class member could have relied on that same evidence in
an individual action. Bouaphakeo, 136 S. Ct. at 1046.
     In resolving whether a common question exists or pre-
dominates, the Supreme Court has emphasized that “Rule 23
grants courts no license to engage in free-ranging merits in-
quiries at the certiﬁcation stage.” Amgen Inc. v. Conn. Ret. Plans
& Tr. Funds, 568 U.S. 455, 466 (2013); see also Messner, 669 F.3d
at 811 (“[T]he court should not turn the class certiﬁcation pro-
ceedings into a dress rehearsal for the trial on the merits.”).
Critically, “Rule 23 allows certiﬁcation of classes that are fated
to lose as well as classes that are sure to win.” Schleicher v.
Wendt, 618 F.3d 679, 686 (7th Cir. 2010). Still the merits are not
completely oﬀ limits. Rule 23 is more than “a mere pleading
standard,” and the court must satisfy itself with a “rigorous
analysis” that the prerequisites of certiﬁcation are met, even
if that analysis has “some overlap with the merits of the plain-
tiﬀ’s underlying claim.” Wal-Mart Stores, Inc. v. Dukes, 564 U.S.
338, 350–51 (2011). We have described this analysis as involv-
ing a “peek at the merits” that is “limited to those aspects of
the merits that aﬀect the decisions essential under Rule 23.”
Schleicher, 618 F.3d at 685.
   The Supreme Court discussed the limits and extent of this
peek in Amgen Inc. v. Connecticut Retirement Plans and Trust
Funds, 568 U.S. 455. There the Court confronted a fraud-on-
the-market securities class action. The underlying securities
fraud claim required a plaintiﬀ to prove, among other things,
a material misstatement or omission and reliance on that mis-
representation. Id. at 460–61. Ordinarily, reliance is a fact-
No. 19-1831                                                       9

intensive individual question that is not conducive to class-
wide resolution. Id. at 462–63. Under the fraud-on-the-market
theory, however, a plaintiﬀ can demonstrate reliance by com-
mon proof, on the inference that a security traded in an eﬃ-
cient market reﬂects all publicly available material infor-
mation, so all buyers presumptively relied on false public
statements when purchasing the security. Id. at 461–62. In or-
der to certify a class under this theory, a plaintiﬀ is required
to aﬃrmatively prove that the market is eﬃcient and that an
alleged misrepresentation was publicly made. Id. at 473. Not
so with materiality, the Supreme Court held.
    The Court gave two reasons why a plaintiﬀ does not need
to establish materiality in order to certify a class but can wait
to prove it at the merits stage. First, materiality is an objective
question that can be proven through common evidence. Id. at
467. Second, the Court emphasized that “there is no risk what-
ever that a failure of proof on the common question of mate-
riality will result in individual questions predominating.” Id.
at 467–68. This is so because materiality is an element of every
plaintiﬀ’s securities-fraud claim and not just a prerequisite to
the class’s fraud-on-the market theory, as publicity and mar-
ket eﬃciency are. Id. at 468, 473–74. “As to materiality, there-
fore, the class is entirely cohesive: It will prevail or fail in
unison. In no event will the individual circumstances of par-
ticular class members bear on the inquiry.” Id. at 460.
    The parties agree that the IRPA's identity element is like
materiality in that it, too, is an objective-inquiry—it asks
whether an attribute would identify a plaintiﬀ to the “ordi-
nary, reasonable viewer or listener,” 765 ILCS 1075/5. Dancel
concedes, however, that her theory is diﬀerent from material-
ity, in that if a class is certiﬁed and it is proven that a username
10                                                    No. 19-1831

is not categorically an identity, Dancel and the class’s claims
would “remain live,” Amgen, 568 U.S. at 474. Each person
could still try to prove, after decertiﬁcation, that his or her
username is an identity in a way diﬀerent from usernames
generally.
    This distinction is not fatal to class certiﬁcation, Dancel ar-
gues, because this court has permitted certiﬁcation even when
there was a risk the court might later need to decertify the
class. In Bell v. PNC Bank, N.A., 800 F.3d 360 (7th Cir. 2015),
we aﬃrmed a district court’s certiﬁcation of a class alleging
PNC had a policy requiring employees to work unpaid over-
time. Id. at 372. We recognized that, if the policy were found
not to exist then the class would be decertiﬁed, and the class
members could still bring individual claims. Those individual
claims, though, “would be based on an entirely diﬀerent legal
theory”—“Employee A alleging that her manager, Manager
B, forced her to work oﬀ-the-clock.” Id. at 378. The class’s pol-
icy-based theory would still “prevail or fail for the class as a
whole.” Id. Similarly, in Costello v. BeavEx, Inc., 810 F.3d 1045
(7th Cir. 2016), we reversed the denial of certiﬁcation to a class
of couriers arguing that they were employees—not independ-
ent contractors—of a delivery company, BeavEx. Id. at 1048–
49. Under state law, all workers were employees unless the
employer could prove three elements, but the district court
thought only the second element (whether the plaintiﬀs per-
formed work outside the usual course of the employer’s busi-
ness) was subject to common proof. Id. at 1059. The district
court refused to consider whether this common question pre-
dominated for fear of deciding the merits of the other ele-
ments. Id. at 1060. We explained that even if only this single
element was subject to common proof, that did not prevent
certiﬁcation. Id. If the plaintiﬀs won on that element, then all
No. 19-1831                                                 11

the couriers would be employees notwithstanding the other
elements; if BeavEx won, then it would not have to relitigate
the second element against each plaintiﬀ. Id. Regardless of the
way the evidence turned out, this common answer would rep-
resent a signiﬁcant aspect of the case. Id.
    Dancel’s theory is diﬀerent from those in Bell and Costello
because it presents a question that is common only if she is
right. If the class in Bell lost on its theory, no member could
argue that PNC had a policy only with respect to her over-
time; nor could an individual courier in Costello argue that
BeavEx’s usual course of business included delivery in his sit-
uation but not the class’s. The question—does this policy ex-
ist? is couriering BeavEx’s usual business?—was common re-
gardless of its answer. If the common proof failed as to that
answer, the plaintiﬀs could not use individualized proof in its
stead. Any individual class member with a claim remaining
would have to rely on diﬀerent proof to answer a diﬀerent
question to establish the defendant’s liability.
    In contrast, the answer to Dancel’s proposed common
question—are usernames categorically identities under the
IRPA?—matters not only for the merits but for commonality.
If the answer to that question is yes, then one signiﬁcant as-
pect of the case can be resolved in the class’s favor (if, as a
factual matter, Groupon used the usernames within the
meaning of the IRPA). But if usernames are not categorically
an identity under the IRPA, and the court decertiﬁed the class,
then the same element would remain entirely subject to dis-
pute for each plaintiﬀ. Nothing signiﬁcant will have been de-
cided, because each member could provide individualized
evidence—her username’s content—on top of the common
evidence to prove her username is an identity. Indeed,
12                                                    No. 19-1831

because each username necessarily has some content,
whether it be meowchristine or isa.tdg or loparse, the individ-
ual claims would not be hindered by the preclusion of a con-
tent-ignorant theory. Class members would be prohibited
only from arguing again that all usernames are categorically
an identity—that is, from certifying another class.
    This diﬀerence arises from the fact that Dancel’s proposed
common question is whether identity is a common or an indi-
vidualized question in the ﬁrst place. Must identity be proven
through “evidence that varies from member to member” (the
username’s content) or can “the same evidence” (its being a
username) “suﬃce for each member to make a prima facie
showing”? Bouaphakeo, 136 S. Ct. at 1045. This is not a question
that can be saved for after certiﬁcation; it is precisely the ques-
tion the court must answer at certiﬁcation. As we said in Bell,
“[a] proposed class of plaintiﬀs must prove the existence of a
common question … but it need not prove that the answer to
that question will be resolved in its favor.” 800 F.3d at 376.
Like PNC, though, Dancel has “conﬂated [these] two inquir-
ies,” id., by failing to separate her argument for why a com-
mon question exists with an argument that the question
should be resolved in her favor. A court cannot decide the lat-
ter, but it must decide the former—and it must police this ﬁne
line or else reduce certiﬁcation to a mere pleading standard.
   The Third Circuit faced a situation like this in Gonzalez v.
Corning, 885 F.3d 186 (3d Cir. 2018). The plaintiﬀ there alleged
that the defendant’s shingles were defectively designed be-
cause some would not last as long as advertised. Id. at 196.
Whether any individual shingle would fail, though, could be
determined only on review of that shingle. Id. The plaintiﬀ
came up with a theory to avoid this problem: the defect was
No. 19-1831                                                  13

not that the individual shingle would fail, but the chance that
any shingle would fail. Id. at 197. This theory presented a com-
mon, shared defect (the chance of failure) distinct from the in-
dividualized defect (the failure), and the plaintiﬀ insisted
that, under Amgen, he could test the merits of his common
theory on a class-wide basis. Id. at 200. The Third Circuit saw
this request for what it was, though—an “attempt to circum-
vent the need to identify a common defect by, in eﬀect, rede-
ﬁning the concept.” Id. at 198. By checking the plaintiﬀ’s su-
perﬁcially common theory for “coherence and legal founda-
tion,” the district court had not found that any class member’s
shingles were not defective and thereby decided the merits in
violation of Amgen; it “merely applied Rule 23’s predomi-
nance requirement.” Id. at 201.
    The same reasoning applies here. Dancel is trying to deﬁne
the concept of identity in a common way so that it covers up
individual questions that each class member might raise. Her
use of the word “categorically” makes her theory universal,
but only in the way “any question becomes universal when it
includes the word ‘all.’” Id. This is not a disingenuous tactic
under Rule 23—it is no diﬀerent from how a securities-fraud
class can paper over the individualized question of reliance
with the fraud-on-the-market theory under which all buyers
are presumed to rely on material public statements. See
Amgen, 568 U.S. at 461. Whether the tactic succeeds, however,
must be determined before class certiﬁcation by considering
the substantive law underlying the putative class’s claims. See
Richard A. Nagareda, Class Certiﬁcation in the Age of Aggregate
Proof, 84 N.Y.U. L. Rev. 97, 104 (2009).
   The district court, then, was right to identify the starting
point as “the substantive elements of plaintiﬀs’ cause of action
14                                                    No. 19-1831

and … the proof necessary for the various elements.” Simer v. Rios,
661 F.2d 655, 672 (7th Cir. 1981) (emphasis added). If the pro-
posed common proof could be enough to carry a prima facie
case on an element for an individual plaintiﬀ, in an individual
case, then that element presents a common question that can
predominate for a class action. Bouaphakeo, 136 S. Ct. at 1045–
47; Messner, 669 F.3d at 815; see also Costello, 810 F.3d at 1060
(“Plaintiﬀs have demonstrated that common questions pre-
dominate by making out a prima facie claim … based on evi-
dence common to the class.”). Here the present dispute is pre-
cisely what evidence is needed to make a prima facie case for
the identity element under the IRPA. Would facts common to
all Instagram usernames (i.e., their innate uniqueness) suﬃce,
or would a plaintiﬀ need to show something more, something
about her username, to meet her initial burden? Though this
question overlaps with the merits, it is also “vital to any sen-
sible decision about class certiﬁcation,” Szabo v. Bridgeport
Machs., Inc., 249 F.3d 672, 674 (7th Cir. 2001), and the district
court was right to decide it before certifying a class. We must
now determine whether the court correctly decided it.
B. The IRPA
    We start with the substantive elements of an IRPA claim.
The IRPA prohibits “us[ing] an individual’s identity for com-
mercial purposes during the individual’s lifetime without
having obtained previous written consent from the appropri-
ate person.” 765 ILCS 1075/30(a). A plaintiﬀ must thus prove
(1) the appropriation of one’s identity, (2) without one’s con-
sent, (3) for another’s commercial beneﬁt. Trannel v. Prairie
Ridge Media, Inc., 987 N.E.2d 923, 929 (Ill. App. Ct. 2013). The
IRPA deﬁnes identity as “any attribute of an individual that
serves to identify that individual to an ordinary, reasonable
No. 19-1831                                                   15

viewer or listener, including but not limited to (i) name, (ii)
signature, (iii) photograph, (iv) image, (v) likeness, or (vi)
voice.” 765 ILCS 1075/5. Name, in turn, “means the actual
name or other name by which an individual is known that is
intended to identify that individual.” Id.
   Dancel argues that all Instagram usernames are names or
identities under the IRPA because an ordinary, reasonable
viewer would know that a username is intended to identify
one and only one user. Because a username is innately unique,
Dancel contends, the viewer would not need to know what
the username is to know that it identiﬁes an individual.
    Dancel supports her categorical rule by comparing
usernames to email addresses, but her analogy cuts against
her. In United States v. Hastie, 854 F.3d 1298 (11th Cir. 2017),
the Eleventh Circuit concluded that email addresses can qual-
ify as “personal information” under the Driver’s Privacy Pro-
tection Act, 18 U.S.C. § 2721, which deﬁnes the term as “infor-
mation that identiﬁes an individual.” Hastie, 854 F.3d at 1301
(citing 18 U.S.C. § 2725(3)). This was so, the court explained,
because “[e]mail addresses often expressly include the ac-
count holder’s name, aﬃliated organization, or other identi-
fying information.” Id. at 1303. As is critical for our purposes,
the court did not hold that email addresses categorically iden-
tify an individual, only that they often did, and they often did
so only because of their content, not their inherent nature as
email addresses. See also Gov't Accountability Project v. U.S.
Dep't of State, 699 F. Supp. 2d 97, 106 (D.D.C. 2010) (recogniz-
ing that email addresses “can be identiﬁed as applying to par-
ticular individuals” (emphasis added)).
   A username’s content, and not its nature, is likewise nec-
essary to decide whether it is an identity under the IRPA.
16                                                 No. 19-1831

Categorically, Instagram usernames identify only Instagram
accounts. The IRPA, however, requires more than that. It de-
mands that an attribute, even a name, serve to identify an in-
dividual. And not just an individual but “that individual,” the
one whose identity is being appropriated. This is a compara-
tive exercise that depends on both the speciﬁc individual and
the speciﬁc appropriated attribute in question and cannot be
solved categorically here. The common evidence that Dancel
proposes she will provide—that usernames are unique, the
Instagram Widget collected usernames, and Groupon’s deal
pages delivered those usernames to visitors—does nothing to
answer the question whether any given username identiﬁes
that speciﬁc individual who is behind that username and its
associated account. So, when Dancel insists that she is not ask-
ing “whether any particular username identiﬁes an individ-
ual,” she gives up the game. Whether the appropriated attrib-
ute serves to identify a particular person is, as the district
court said, the “essence of determining ‘identity’ under the
IRPA.” Dancel cannot answer this question for herself or for
any putative class member with only her proposed common
evidence, and so she cannot develop, for each class member,
a common prima facie case under the identity element of an
IRPA claim.
    Dancel insists that this individualized inquiry is incon-
sistent with the IRPA’s broad scope, which is intended to pro-
tect lay people’s identities. She argues that the content of a
username could matter only if the person needed to know to
whom the username belonged from just the username itself.
The Illinois common law had just such a “notoriety” element,
whereby the plaintiﬀ needed to show her identity had “intrin-
sic value,” like a celebrity’s might. Dwyer v. Am. Exp. Co., 652
N.E.2d 1351, 1356 (Ill. App. Ct. 1995). As Dancel rightly notes,
No. 19-1831                                                   17

though, the IRPA has supplanted the common law right of
publicity. 765 ILCS 1075/60; Trannel, 987 N.E.2d at 928. So, a
plaintiﬀ need not show her identity has value to prove a claim
under the IRPA. She still must show, however, that it is her
identity that the defendant appropriated. The Appellate
Court in Tranell v. Prairie Ridge Media, thus, did not ask
whether a reasonable person would know who Karen Tranell,
winner of the 2009 McHenry County Living gardening contest,
was based only on her photograph. 987 N.E.2d at 926. It did,
however, emphasize that the photograph “depict[ed] plaintiﬀ
and her daughter smiling at the camera,” and reviewed sev-
eral other photographs for whether the subjects were recog-
nizable. Id. An individual’s photograph, like her name, is ex-
pressly protected by the IRPA, but that protection extends
only so far as that photograph, that name, that username
“serves to identify that individual to an ordinary, reasonable
viewer.” 765 ILCS 1075/5 (emphasis added). Not all photo-
graphs, names, or usernames will do so, and whether any
does must be answered with individual proof beyond the cat-
egory into which the attribute falls.
    Even if individual proof is necessary, Dancel proposes that
she could provide it through class members’ aﬃdavits attest-
ing to their ownership of their usernames. We have permitted
district courts, in their discretion, to use individual aﬃdavits
to identify class members after liability is established class-
wide, Mullins v. Direct Dig., LLC, 795 F.3d 654, 672 (7th Cir.
2015), or to resolve individual merits questions after resolu-
tion of class issues, Beaton, 907 F.3d at 1030. Dancel’s proposal
goes much further than this. She asks to use class members’
aﬃdavits not to clean up individual questions left over after
some other, common question has been decided, but to pro-
vide individual proof for the same question that she says can
18                                                   No. 19-1831

be resolved through common proof. Given this contradiction,
we need not decide whether it would ever be permissible to
resolve the IRPA’s identity element this way (for example if
she had identiﬁed some other, predominating common ques-
tion). The district court here did not abuse its discretion.
    We emphasize that neither we nor the district court have
decided the merits of any putative class member’s claim.
Some Instagram usernames—maybe a great many of them—
might qualify as identities under the broad deﬁnition in the
IRPA. An ordinary, reasonable viewer might recognize that
meowchristine serves to identify Christine Dancel, or that
isa.tdg, artistbarbie, and loparse serve to identify their respec-
tive users. We cannot say. What we can say is, under the IRPA,
that ordinary, reasonable viewer would need to have evi-
dence of which username, which account, and which person
it was linking before it could make that decision. This individ-
ualized evidentiary burden prevents identity from being a
predominating common question under Rule 23(b)(3).
                        IV. Conclusion
    We aﬃrm the district court’s order denying class certiﬁca-
tion.
