                                              Filed:   July 24, 2012

                  UNITED STATES COURT OF APPEALS
                      FOR THE FOURTH CIRCUIT


                            No. 11-1759
                        (1:10-cv-03472-RDB)


EQUAL EMPLOYMENT OPPORTUNITY COMMISSION,

                Petitioner - Appellant,

           v.

RANDSTAD; RANDSTAD NORTH AMERICAN LP; RANDSTAD GENERAL
PARTNERS (US); RANDSTAD US LP; RANDSTAD INHOUSE SERVICES LP,

                Respondents - Appellees.



                             O R D E R


           The Court amends its opinion filed July 18, 2012, as

follows:

           On page 7, item (1) of the numbered list -- the word

“DOCUMENTS” in upper case is corrected to read “Documents.”

                                     For the Court – By Direction


                                           /s/ Patricia S. Connor
                                                     Clerk
                       PUBLISHED


UNITED STATES COURT OF APPEALS
             FOR THE FOURTH CIRCUIT


EQUAL EMPLOYMENT OPPORTUNITY          
COMMISSION,
              Petitioner-Appellant,
                v.
RANDSTAD; RANDSTAD NORTH                  No. 11-1759
AMERICAN LP; RANDSTAD GENERAL
PARTNERS (US); RANDSTAD US LP;
RANDSTAD INHOUSE SERVICES LP,
            Respondents-Appellees.
                                      
       Appeal from the United States District Court
        for the District of Maryland, at Baltimore.
            Richard D. Bennett, District Judge.
                  (1:10-cv-03472-RDB)

                  Argued: May 15, 2012

                  Decided: July 18, 2012

    Before DAVIS and KEENAN, Circuit Judges, and
 James R. SPENCER, United States District Judge for the
             Eastern District of Virginia,
                sitting by designation.



Reversed and remanded by published opinion. Judge Davis
wrote the opinion, in which Judge Keenan and Judge Spencer
joined.
2                     EEOC v. RANDSTAD
                         COUNSEL

ARGUED: Susan Ruth Oxford, U.S. EQUAL EMPLOY-
MENT OPPORTUNITY COMMISSION, Washington, D.C.,
for Appellant. John S. Snelling, LEWIS BRISBOIS BIS-
GAARD & SMITH, Atlanta, Georgia, for Appellees. ON
BRIEF: P. David Lopez, General Counsel, Lorraine C.
Davis, Acting Associate General Counsel, U.S. EQUAL
EMPLOYMENT OPPORTUNITY COMMISSION, Wash-
ington, D.C., for Appellant. Christopher W. Mahoney,
DUANE MORRIS, LLP, Washington, D.C., for Appellees.


                          OPINION

DAVIS, Circuit Judge:

   Kevin Morrison, a resident of Maryland, was born in
Jamaica and cannot read or write English. He filed a charge
of discrimination with the Equal Employment Opportunity
Commission ("EEOC" or Commission) asserting that Appel-
lee Randstad, which provides temporary staffing services to
client companies, terminated his employment pursuant to a
requirement that its employees read and write English. Morri-
son alleged that Randstad’s literacy policy violated Title VII
of the Civil Rights Act of 1964, as amended, 42 U.S.C.
§ 2000e, et seq. Two years later, in an amended charge, Mor-
rison asserted that the literacy policy violated the Americans
with Disabilities Act (ADA), 42 U.S.C. § 12101, et seq.,
because he has a learning disability. In investigating Morri-
son’s charges, the EEOC served an administrative subpoena
on Randstad, which Randstad resisted, in part. When the
EEOC sought judicial enforcement of its subpoena, the dis-
trict court denied relief. For the following reasons, we reverse
the order of the district court denying enforcement.
                     EEOC v. RANDSTAD                       3
                              I.

                             A.

   Randstad has 600 branch offices in thirty-seven states,
including thirteen offices in Maryland. In any given week the
company employs a total of approximately 45,000 individu-
als: 1,800 (Randstad’s "internal talent") who recruit, screen,
and hire temporary and permanent employees for client com-
panies, and 43,200 (Randstad’s "external talent") who are on
assignment to Randstad’s customers. Randstad focuses its
staffing services on two main types of clients: "light indus-
trial" clients that use laborers in manufacturing or warehouse
settings, and "administrative" clients that use clerical and
administrative employees in office settings.

   In August 2005, Morrison approached Randstad’s Hagers-
town, Maryland office, seeking temporary employment. He
was ineligible for assignment with Randstad’s administrative
clients because he does not have a high school diploma or its
equivalent, and so Randstad placed him in industrial posi-
tions. He first successfully completed a month-long assign-
ment as a mail clerk for Randstad client Good Humor. In
September 2005, Randstad referred Morrison to two tempo-
rary warehouse positions, one at Ashley Home Store, Inc.,
and the other at Cosmic Pet Products, Inc. According to Rand-
stad, both clients terminated Morrison within days because of
poor performance. During that time Randstad was not aware
that Morrison could not read or write.

   Morrison did not seek any additional assignments for more
than a year. In September 2006, however, he returned to
Randstad’s Hagerstown office in search of another temporary
work assignment. As before, Randstad sent him to fill a ware-
house job, this time with Lenox, Inc. Upon arriving at
Lenox’s facilities, he was asked to fill out some forms.
Unable to read or write, Morrison called his placement man-
ager at Randstad to ask if she would help him complete the
4                     EEOC v. RANDSTAD
forms. According to Morrison, the manager told him, "We
don’t hire people who cannot read. Come back when you
learn to read." J.A. 30. On September 28, 2006, Randstad
ended Morrison’s assignment and informed him that, although
it remained willing to place him in the future, it would do so
only if he were to develop remedial reading and writing skills.

   On January 5, 2007, Morrison filed a charge of discrimina-
tion with the EEOC. A checkbox on the form identified the
type of discrimination as national origin discrimination and
the following allegations stated:

    I. On September 29, 2006, Randstad denied me
    placement in a position with its customer Lenox.
    Randstad had previously placed me in jobs in 2005
    and 2006. Randstad sent me to Lenox where I was
    given forms to complete and return. I called Rand-
    stad and spoke with Renee. I asked Renee if Rand-
    stad could assistance [sic] me in completing the
    forms I received from Lenox. I was told "We don’t
    hire people who can not read. Come back when you
    learn to read."

    II. I was given no explanation for Randstad’s dis-
    criminatory action.

    III. I believe I have been discriminated against in
    violation of Title VII of the Civil Rights Act of
    1964, as amended, regarding failure to hire because
    of my national origin, Jamaican.

J.A. 30. The EEOC served a copy of the charge on Randstad
on February 1, 2007, and began to investigate.

   Randstad timely responded to the charge. It admitted that
Morrison was terminated because he could not read, but
denied that the termination was the result of national origin
discrimination. Rather, Randstad explained, the company
                         EEOC v. RANDSTAD                             5
maintained an unwritten policy against hiring people who
cannot read because "virtually all of the assignments that
Randstad is called upon to fill require reading and/or writing
skills." J.A. 36. As for the administrative positions, most of
Randstad’s clients have minimum education requirements;
indeed, the EEOC has since conceded that Morrison was not
eligible for an administrative position. As for Randstad’s
industrial clients, the company explained that although there
is no written policy requiring that employees be literate, "the
inability to read and comprehend safety notices, warnings, or
machinery operating instructions potentially [would] place[ ]
Mr. Morrison and his co-workers at risk of serious injury."
J.A. 36. Because the company’s unwritten literacy policy was
justified, Randstad argued, and because there was "no evi-
dence of discriminatory animus on Randstad’s behalf toward
Mr. Morrison," the EEOC should enter a "no cause" finding
in Morrison’s case. Id.

   The EEOC investigation remained open for approximately
two years without the Commission issuing a Request for
Information or seeking any other information concerning
Morrison’s allegations. During that time Morrison underwent
a psychological evaluation that revealed "an intellectual dis-
ability (mild retardation) that prevents him from reading and
writing." J.A. 11. On January 30, 2009, over two years after
filing the original charge, Morrison filed an amended charge
of discrimination. The amended charge contained two
changes. First, instead of the checkbox for national origin dis-
crimination, the checkbox for disability discrimination was
marked. Second, in the last sentence of the factual allegation
section, the allegation that Randstad’s actions violated Title
VII was replaced with the following: "I believe I have been
discriminated against in violation of the [ADA] regarding fail-
ure to accommodate because of my disability." J.A. 39. As the
EEOC explained, Morrison allegedly has a learning disability
that prevents him from learning to read and write English.1
  1
   The record before us does not disclose the identity of the person who
physically completed the charging documents Morrison filed with the
6                       EEOC v. RANDSTAD
   Randstad was given notice of the amended charge on Feb-
ruary 3, 2009. In response, Randstad stated that its original
position statement was "largely unaffected" by the amend-
ment, but it "supplement[ed]" its prior letter by arguing that
Morrison’s charge of disability discrimination lacked merit
because illiteracy is only a protected disability under the ADA
if it "stems from ‘an organic dysfunction rather than a lack of
education,’" J.A. 44 (quoting Morisky v. Broward County, 80
F.3d 445 (11th Cir. 1996)), and there was "no evidence that
Mr. Morrison’s illiteracy follows from a physical or mental
impairment." Id. Randstad also argued that, even if Morri-
son’s illiteracy was a protected disability, he had an obligation
to inform Randstad of the impairment but failed to do so.

   The EEOC issued a Request for Information ("RFI") seek-
ing, among other things, information about any literacy
requirements Randstad imposes, and a list of all position
assignments made by Randstad’s Hagerstown office from
2006 through 2009.2 In response, Randstad explained that
although the company did not have a "formal" literacy policy,
"a significant number of assignments . . . require reading and
writing skills," and so Randstad "requires talent to be at least
literate at a remedial level." J.A. 53. As for information on
other position assignments, Randstad objected, arguing the
request was "unduly burdensome" and that the information
requested was "irrelevant to the resolution of [Morrison’s]
charge." J.A. 54.

   The EEOC maintained that Morrison’s charge authorized it
to obtain the requested information, and not just for Rand-

EEOC. We think it is reasonably inferable (as our colloquy with counsel
at oral argument indicated) that an EEOC staffer completed the typed
forms.
   2
     In September 2009 the EEOC had issued a letter finding Randstad in
violation of the ADA, but revoked that determination and reopened the
investigation the next month.
                          EEOC v. RANDSTAD                               7
stad’s Hagerstown office. Thus, on January 15, 2010, it issued
an administrative subpoena that requested, among other
things, "documents or a data compilation setting forth all
position assignments made by [Randstad] during the period
January 1, 2005 through the present." J.A. 59. After Randstad
objected to the time period and nationwide scope of the sub-
poena, the Commission narrowed the geographic scope to
Randstad’s thirteen Maryland offices but otherwise insisted
on receiving information on all position assignments made by
those offices for the years 2005 through 2009. Randstad pro-
vided information about the positions to which Morrison him-
self was assigned, at Good Humor, Lenox, and the two other
temporary warehouse positions in September 2005, but other-
wise refused to comply.

   Thus, the EEOC filed the instant petition for enforcement
of the disputed portion of the subpoena ("the requested infor-
mation") namely:

      (1) Documents or a data compilation setting
          forth all non-administrative position assign-
          ments made by Randstad’s thirteen Maryland
          offices from 2005 through 2009, including
          position title, client name, and the date the
          assignment was filled;3

      (2)   Copies of job orders and job descriptions for
            each position;

      (3)   Copies of all applications for each position; and

      (4)   A statement for each position as to whether
  3
    In fact the subpoena also requested information on administrative posi-
tions, for which Morrison was concededly unqualified even absent a liter-
acy requirement. On appeal the EEOC has abandoned that request.
Accordingly, for our purposes we consider the EEOC’s request as limited
to non-administrative positions.
8                     EEOC v. RANDSTAD
          reading and writing was required for the posi-
          tion.

   The EEOC’s petition for enforcement asserted that both
Title VII and the ADA, combined with Morrison’s original
and amended charges of discrimination, authorized it to
obtain the information and documents sought under the sub-
poena. Title VII authorized the investigation, the Commission
asserted, because Randstad’s literacy requirement "may have
a disparate impact on Jamaicans and others who are not fluent
in English due to their national origin." J.A. 15. In addition,
the Commission asserted, because Morrison’s illiteracy
resulted in part from a learning disability, and because
"[d]iscrimination based on ability to read may constitute a
violation of the ADA," J.A. 16, the subpoena was also autho-
rized by the ADA. The Commission argued that information
about all of Randstad’s positions in Maryland was relevant
because if (contrary to Randstad’s representation) some Rand-
stad positions do not actually require reading skills, the fact
that Randstad nevertheless hires only people who can read
could be evidence of discrimination. Such evidence could also
"uncover the existence of other individuals who have been
harmed by Randstad’s literacy policy." J.A. 19.

   The district court ordered Randstad to show cause why the
subpoena should not be enforced pursuant to Title VII and/or
the ADA. In its answer, Randstad first argued that Morrison’s
charges of discrimination did not authorize the investigation
because although Randstad generally does not give assign-
ments to people who cannot read, that is not because the com-
pany discriminates against foreign-born or learning-disabled
individuals, but rather because reading "is an implicit require-
ment for virtually every light industrial client assignment."
J.A. 66-67. While Randstad "has never maintained a policy
against hiring individuals who cannot read and write," it
argued, it "typically has no work for talent who lack remedial
reading skills." J.A. 67. Randstad’s human resources manager
asserted that it sometimes fills positions that "involve purely
                      EEOC v. RANDSTAD                        9
manual labor where reading may not be required," but such
positions are "rare," "are not a focus of Randstad’s business,"
and "would ordinarily not be in a factory or warehouse set-
ting." J.A. 89.

   Second, Randstad argued that, to the extent the EEOC
relies on the ADA, Morrison’s amended charge was "un-
timely on its face" because it alleged a "new theory of recov-
ery" and therefore did not relate back to the date of his
original charge. J.A. 78. Third, Randstad argued that, even if
one or both of Morrison’s charges were timely, information
on positions other than the ones to which Morrison was
assigned was not "relevant" because Morrison did not allege
"systemic discrimination or that Randstad’s policies have a
disparate impact" on a "protected class." J.A. 79. Fourth,
Randstad argued, even if some of the requested information
was relevant, the subpoena should not be enforced because
complying with the subpoena would be unduly burdensome.
Its Maryland branches made over 100,000 temporary assign-
ments during the time period of the subpoena. Due to the
structure of Randstad’s databases, compiling the requested
information would require a database administrator, IT devel-
oper, and business analyst each to spend 40 hours reviewing
100,000 job orders, at a labor cost of $14,000 to $19,000.

    The EEOC argued it had jurisdiction to investigate under
both Title VII and the ADA because Morrison’s original
charge remained in effect and the amended charge’s allega-
tion of disability discrimination "flow[s] from the national
origin discrimination because they are both the result of the
same literacy requirement." J.A. 115. It argued the full scope
of the materials sought were relevant because "Respondent’s
refusal to assign Morrison based on his inability to read and
write may not be an isolated incident, but rather may be an
instance of a larger discriminatory practice of turning away
illiterate individuals when there is available work within their
skill sets." J.A. 111. Moreover, the EEOC argued, Randstad’s
position that it "typically has no work for talent who lack
10                     EEOC v. RANDSTAD
remedial reading skills," J.A. 67, was belied by the fact that
Morrison himself was placed in several positions. Finally, it
argued, there was no undue burden because Randstad’s cost
estimate could not have been correct (if it were, it would
mean the three employees preparing the materials would
receive annual salaries of nearly $330,000), and in any event
a showing that "production will tie-up three employees for a
week . . . do[es] not rise to the level of establishing undue bur-
den." J.A. 117.

                               B.

   At a hearing on the Commission’s petition, the EEOC reit-
erated its position that there were two independent bases for
the Commission’s authority to issue the subpoena: Title VII
and the ADA. With respect to Title VII, Morrison’s original
charge alleged that Randstad’s literacy requirement discrimi-
nated on the basis of national origin. The Commission
explained that the information requested was relevant to
alleged national origin discrimination because "a reading
requirement is going to have a disparate impact on people of
varying national origin." J.A. 131. Citing a Department of
Education study, the Commission explained, "[O]f the people
who read at the lowest levels, twenty-six percent of them are
people who are learning English currently, so there is a broad
overlap between people who are unable to read and people
who have a unique national origin." J.A. 133.

   The second basis of authority for the subpoena, the Com-
mission argued, was the ADA, arising out of Morrison’s
amended charge, which alleged that the literacy requirement
discriminated on the basis of disability. The Commission rec-
ognized that if the amended charge had been filed as a stand-
alone charge, it would have been untimely. The Commission
argued that the amended charge related back to the original
charge, however, because the disability discrimination claim
arises out of the same factual allegations raised in the original
charge, and the amended charge merely altered the statute
                           EEOC v. RANDSTAD                                 11
under which "the alleged discrimination constitutes an unlaw-
ful employment practice." J.A. 122.

   The district court denied the EEOC’s petition to enforce the
subpoena. See EEOC v. Randstad, 765 F. Supp. 2d 734, 742
(D. Md. 2011). As for Title VII, the district court rejected on
relevance grounds Morrison’s national origin discrimination
claim as a basis for enforcing the subpoena.4 That is, assum-
ing Morrison’s original charge triggered Title VII as a basis
for the EEOC’s authority to investigate, the court disagreed
with the Commission’s alleged factual nexus between
national origin discrimination and literacy requirements.
Information related to reading and writing requirements for
particular positions "relates to the matter of reading and writ-
ing ability, not national origin," the court stated. J.A. 132. In
particular, the court expressed skepticism about the causal
link between Morrison’s Jamaican origin and his illiteracy:

      Jamaica is an English speaking island. It’s not Haiti
      . . . . I’m not really sure where you make the jump
      from a national origin claim of discrimination to the
      matter of literacy in English, particularly from a
      country that, in fact, does have English as its basic
      native language. Clearly there is what is known as
      Patois spoken by other members of the community
      there, sometimes those with lesser education. But
      English is clearly spoken in Kingston and in Mon-
      tego Bay. English is the spoken language in Jamaica.

J.A. 134. Thus, the court apparently concluded, none of the
information requested in the subpoena would be relevant to
Morrison’s charge of national origin discrimination.

   As for the ADA, the district court rejected the Commis-
sion’s relation-back argument, reasoning that when the
  4
    The district court’s analysis under Title VII is revealed only in the tran-
script of the hearing. The written opinion addresses only the ADA.
12                    EEOC v. RANDSTAD
amended charge added the ADA claim, "a new theory of
recovery" was put forward and "an amendment to an EEOC
charge alleging a new theory of recovery does not relate back
to the original charge." Randstad, 765 F. Supp. 2d at 740 (cit-
ing Evans v. Tech. Applications & Serv. Co., 80 F.3d 954, 963
(4th Cir. 1996)). Thus, the court concluded it did not have
jurisdiction to enforce the subpoena under the ADA.

   The court also offered two alternative grounds for declining
to enforce the subpoena under the ADA. First, the court found
that even if it had jurisdiction under the ADA, any informa-
tion beyond that which Randstad had already produced was
irrelevant to Morrison’s charge of disability discrimination by
Randstad’s Hagerstown office. The court ruled that because
the subpoena requested information about all Randstad posi-
tions (including administrative positions, for which Morrison
was concededly unqualified), for all Maryland offices (even
though Morrison solely sought employment by Randstad in
its Hagerstown office), and for a five-year period after Morri-
son’s termination (even though Morrison was employed by
Randstad only from August 2005 until September 2006), the
information requested was beyond the scope permitted by the
amended charge. Id. at 741-42. Second, the court ruled that,
even if it had jurisdiction under the ADA or Title VII, and
even if the requested materials were relevant, the cost of com-
pliance with the subpoena—$14,000 to $19,000 according to
Randstad—rendered the requests unduly burdensome. Id. at
742.

  The EEOC sought reconsideration, which the district court
denied, and then timely appealed.

                              II.

   Title VII proscribes discriminatory employment practices
on the basis of, among other things, national origin. 42 U.S.C.
§ 2000e-2. The ADA proscribes discriminatory employment
practices based on disability, including an employer’s failure
                      EEOC v. RANDSTAD                        13
to provide a reasonable accommodation. 42 U.S.C.
§ 12112(a), (b)(5)(A). Each statute authorizes the EEOC to
investigate instances of discrimination, but only if a charge of
discrimination has been made with respect to a particular per-
son or entity. 42 U.S.C. § 2000e-5(b); 42 U.S.C. § 12117(a).

   If a charge of discrimination triggers the EEOC’s authority
to investigate under Title VII or the ADA, the EEOC may
access "any evidence . . . that relates to unlawful employment
practices covered by [the statute] and is relevant to the charge
under investigation." 42 U.S.C. § 2000e-8(a); see also 29
U.S.C. § 161 (describing the investigatory powers of the
National Labor Relations Board, which the EEOC also may
exercise pursuant to Title VII, see 42 U.S.C. § 2000e-9, and
the ADA, see 42 U.S.C. § 12117(a)). If a respondent does not
comply voluntarily with requests for such evidence, the
EEOC may issue an administrative subpoena, 29 U.S.C.
§ 161(a), and may petition for enforcement in federal district
court. Id. § 161(2); see also EEOC v. Shell Oil Co., 466 U.S.
54, 65 (1984) (explaining that the existence of a charge of dis-
crimination relevant to material being sought through an
administrative subpoena is a jurisdictional prerequisite to the
enforcement of the subpoena).

   A district court’s role in enforcing administrative subpoe-
nas is "sharply limited." EEOC v. City of Norfolk Police
Dep’t, 45 F.3d 80, 82 (4th Cir. 1995). To obtain judicial
enforcement of a subpoena, the EEOC need demonstrate only
that "(1) it is authorized to make such investigation; (2) it has
complied with statutory requirements of due process; and (3)
the materials requested are relevant." Id. The process of
reviewing an administrative subpoena for judicial enforce-
ment "is not one for a determination of the underlying claim
on its merits; Congress has delegated that function to the dis-
cretion of the administrative agency." EEOC v. Am. & Efird
Mills, Inc., 964 F.2d 300, 303 (4th Cir. 1992). To establish its
authority to investigate, the EEOC need only present an "ar-
guable" basis for jurisdiction. Norfolk Police Dep’t, 45 F.3d
14                    EEOC v. RANDSTAD
at 85. As long as jurisdiction is "plausible" and not "plainly
lacking," EEOC v. Fed. Exp. Corp., 558 F.3d 842, 848 (9th
Cir. 2009), the subpoena should be enforced, unless the party
being investigated demonstrates that the subpoena is unduly
burdensome. EEOC v. Maryland Cup Corp., 785 F.2d 471,
476 (4th Cir. 1986).

   We review the factual findings underlying a district court’s
enforcement determination of an administrative subpoena for
clear error and its legal conclusions de novo. Solis v. Food
Emp’rs Labor Relations Ass’n, 644 F.3d 221, 226 (4th Cir.
2011). The district court’s ultimate decision whether and to
what extent to enforce a subpoena is reviewed for abuse of
discretion. NLRB v. Carolina Food Processors, Inc., 81 F.3d
507, 510 (4th Cir. 1996).

   We first explain why, contrary to the district court’s con-
clusion, the EEOC had authority to investigate Morrison’s
charges under both the ADA and Title VII. We then explain
why the requested materials were within the scope of the
Commission’s investigatory authority. The applicable legal
standards thus clarified, we conclude that the Commission is
entitled to an order enforcing its subpoena.

                              A.

  We first address whether the EEOC had authority to seek
enforcement of the subpoena under the ADA and/or under
Title VII. This requires that we decide (1) whether the
amended charge alleging an ADA violation relates back to the
date the original charge was filed, and (2) whether the original
charge alleging a Title VII violation continued to trigger the
EEOC’s investigatory authority even after the amended
charge was filed.

                               1.

  As explained above, Morrison’s amended charge, filed on
January 30, 2009, alleged that Randstad discriminated against
                           EEOC v. RANDSTAD                               15
him by refusing to accommodate his alleged learning disabil-
ity, and thereby violated the ADA. As an original charge, the
ADA charge clearly would have been untimely. The question
on appeal is whether the amended charge, which alleged the
same facts as the original charge (refusal to give him tempo-
rary employment because he could not read) but asserted that
those facts violated a different statute (the ADA instead of
Title VII) relates back to January 5, 2007, the filing date of
the original charge.

   EEOC regulations provide that an amended charge will
relate back to "the date the charge was first received" if the
amendment (1) "cure[s] technical defects or omissions,
including failure to verify the charge," (2) "clarif[ies] and
amplif[ies] allegations made therein," or (3) "alleg[es] addi-
tional acts which constitute unlawful employment practices
related to or growing out of the subject matter of the original
charge." 29 C.F.R. § 1601.12(b).5 As noted, the factual allega-
tions in Morrison’s two charges were identical: that Randstad
denied him placement because it maintains a policy of not hir-
ing people who cannot read. Morrison originally alleged that
the literacy requirement was discriminatory because it
imposed unwarranted disadvantages on people who, like him,
were from another country. In his amended charge, he alleged
that the same literacy requirement, which led to the same
adverse employment decision, was discriminatory for a differ-
ent reason: it disadvantaged people who, like him (he had
later learned), have a learning disability.
  5
   In full the regulation reads:
      A charge may be amended to cure technical defects or omissions,
      including failure to verify the charge, or to clarify and amplify
      allegations made therein. Such amendments and amendments
      alleging additional acts which constitute unlawful employment
      practices related to or growing out of the subject matter of the
      original charge will relate back to the date the charge was first
      received.
29 C.F.R. § 1601.12(b).
16                        EEOC v. RANDSTAD
   The Commission argues Morrison’s amended charge
"merely clarifie[d] that there is another possible explanation
for the employment action referenced in the original charge:
disability discrimination." Appellant’s Br. at 26. The Com-
mission argues that Morrison’s amended charge relates back
under the "clarify and amplify" prong of § 1601.12(b) because
(1) § 1601.12(b) is a reasonable exercise of the EEOC’s
authority under the ADA and entitled to deference, and (2) its
interpretation of § 1601.12(b) as applying to Morrison’s
amendment is also reasonable and entitled to deference. We
agree.

   Congress has expressly delegated to the EEOC the author-
ity to promulgate "suitable procedural regulations to carry out
the provisions of" Title VII and the ADA. 42 U.S.C. § 2000e-
12(a). Section 1601.12(b) is a reasonable exercise of that
authority. Indeed, Randstad does not argue § 1601.12(b)
exceeded the EEOC’s authority, and for good reason. We
have recognized the "wide discretion" Congress granted the
EEOC to promulgate procedural regulations governing dis-
crimination charges. EEOC v. Bethlehem Steel Corp., 765
F.2d 427, 429 (4th Cir. 1985). In Edelman v. Lynchburg Col-
lege, 535 U.S. 106 (2002), the Court unanimously upheld a
different aspect of 29 C.F.R. § 1601.12(b) as a reasonable
exercise of the EEOC’s authority under 42 U.S.C. § 2000e-
12(a).6 As Justice O’Connor observed in addressing yet
another aspect of the EEOC’s administrative processes, defer-
   6
     In Edelman the Court considered § 1601.12(b)’s pronouncement that
although a charge of discrimination must be "under oath or affirmation,"
42 U.S.C. § 2000e-5(b), such verification constitutes an "amend[ment] to
cure technical defects or omissions" and therefore relates back to the date
an original, unverified charge was filed. 29 C.F.R. § 1601.12(b). The
majority upheld that interpretation, and indeed considered it "not only a
reasonable one, but the position we would adopt even if there were no for-
mal rule and we were interpreting the statute from scratch." 535 U.S. at
114. The other justices also agreed the EEOC’s interpretation was a rea-
sonable exercise of the EEOC’s authority. See id. at 119 (Thomas, J., con-
curring); id. at 121 (O’Connor, J., concurring in the judgment).
                      EEOC v. RANDSTAD                       17
ence to the EEOC is "particularly appropriate" when it comes
to EEOC regulations involving a "technical issue of agency
procedure." EEOC v. Commercial Office Prods., 486 U.S.
107, 125 (1988) (O’Connor, J., concurring). Just as the Edel-
man Court upheld the EEOC’s interpretation of Title VII as
permitting relation back of a verified charge to the filing date
of a prior unverified charge, we hold that the EEOC acted rea-
sonably in interpreting the ADA as permitting relation back
of a charge that "clarif[ies] and amplif[ies] allegations" made
in a prior charge.

   We also find reasonable the EEOC’s interpretation of
§ 1601.12(b) as permitting relation back of the amended
charge here. As noted, § 1601.12(b) permits an amended
charge to relate back if it "clarif[ies] and amplif[ies] allega-
tions made" in a prior timely charge. In arguing that Morri-
son’s amended charge relates back, the EEOC interprets the
phrase "clarif[ies] and amplif[ies] allegations" as encompass-
ing amended charges in which, as here, the charging party
makes no new factual allegations but rather solely revises his
or her charge to allege that the same facts constitute a viola-
tion of a different statute. An agency’s interpretation of its
own regulations is "controlling unless plainly erroneous or
inconsistent with the regulation." Auer v. Robbins, 519 U.S.
452, 461 (1997) (internal quotation marks omitted); cf. Beth-
lehem Steel, 765 F.2d at 429 (upholding EEOC’s interpreta-
tion of charge-filing regulation because the interpretation was
"reasonable").

   The EEOC’s interpretation is not inconsistent with
§ 1601.12(b), and we see no reason to find it "plainly errone-
ous." Charge-filing time limits serve "to encourage a potential
charging party to raise a discrimination claim before it gets
stale, for the sake of a reliable result and a speedy end to any
illegal practice that proves out," Edelman, 535 U.S. at 112-13,
and to "protect employers from the burden of defending
claims arising from employment decisions that are long past,"
Delaware State Coll. v. Ricks, 449 U.S. 250, 256-57 (1980).
18                     EEOC v. RANDSTAD
Interpreting § 1601.12(b) as applying to amended charges that
alter solely the statutory basis or legal theory of recovery is
entirely consistent with these purposes. Morrison’s amend-
ment did not assert a "stale" claim because it did not allege
any discriminatory incidents other than those already included
in the original charge. Rather, it asserted that the same
adverse employment action was at least in part the product of
a different type of discrimination: disability discrimination.
Relating back the ADA charge to the date of the original
charge does not require Randstad to defend against a "stale"
claim arising from an employment decision that is "long
past." Moreover, there is "no reason to suspect that the inter-
pretation does not reflect the agency’s fair and considered
judgment on the matter," and the Commission’s position is
not a "post hoc rationalization" advanced simply to "defend
past agency action against attack." Auer, 519 U.S. at 462. This
is also not a situation where "the underlying regulation does
little more than restate the terms of the statute itself," in which
case Auer deference would be unwarranted. Gonzales v. Ore-
gon, 546 U.S. 243, 257 (2006).

   For these reasons, we defer to the EEOC’s promulgation of
§ 1601.12(b) and its interpretation thereof. Accord Washing-
ton v. Kroger, 671 F.2d 1072, 1075-76 (8th Cir. 1982) (hold-
ing that, based on an earlier version of § 1601.12(b), an
amended charge relates back where it alleges the same facts
as the original charge even though the "nature of discrimina-
tion alleged" is different) (citing 29 C.F.R. § 1601.11(b)
(1973)); Sanchez v. Standard Brands, Inc., 431 F.2d 455, 464
(5th Cir. 1970) (also citing the precursor to § 1601.12(b), and
allowing a national origin discrimination charge to relate back
to the date of a prior sex discrimination charge because "a
charging party’s failure to attach the correct legal conclusion
to the factual allegations contained in a charge of discrimina-
tion is a mere technical defect"); see also id. at 462 ("The
selection of the type of discrimination alleged, i.e., the selec-
tion of which box to check, is in reality nothing more than the
attachment of a legal conclusion to the facts alleged. In the
                           EEOC v. RANDSTAD                                19
context of a statute like Title VII it is inconceivable that a
charging party’s rights should be cut off merely because he
fails to articulate correctly the legal conclusion emanating
from his factual allegations.").7

   As noted above, the district court relied on Evans, 80 F.3d
at 963, for the proposition that "an amendment to an EEOC
charge alleging a new theory of recovery does not relate back
to the original charge." Randstad, 765 F. Supp. 2d at 740.
That reliance was misplaced. First, Evans was a case deciding
the merits of a discrimination claim at the summary judgment
stage, whereas this case presents a proceeding to enforce an
administrative subpoena. Because the strength of the nexus
between factual allegations in an original charge and a theory
of recovery requires some degree of inquiry into the merits,
and because the EEOC has presented a plausible nexus here,
Evans is of limited authority for refusing to enforce the
EEOC’s subpoena. Second, in Evans, the plaintiff filed her
private lawsuit very shortly after amending her charge, which
prevented the local agency from investigating her allegation
of age discrimination. A crucial reason we rejected the plain-
tiff’s relation-back argument in Evans was because permitting
relation back in those circumstances "depriv[ed] the employer
of adequate notice and result[ed] in a failure to investigate by
the responsible agency." Evans, 80 F.3d at 963. This case
presents the opposite scenario. As the EEOC cogently
explains, "[N]ot only has no private lawsuit been filed, but the
dispute exists because the EEOC is attempting to complete its
investigation of Morrison’s discrimination claims." Appel-
lant’s Br. at 33. Third, although pursuant to the Age Discrimi-
nation in Employment Act, the statute at issue in Evans, the
EEOC has determined that a charge alleging a violation of
one statute may be amended to allege "that the alleged dis-
  7
    The reasoning in Sanchez, quoted in text, seems especially apt in a
case, such as the case before us, in which the basis for the charging party’s
allegation is the alleged discriminatory impact of a facially neutral literacy
policy.
20                         EEOC v. RANDSTAD
crimination constitutes an unlawful employment practice
under another statute administered and enforced by the Com-
mission," 29 C.F.R. § 1626.22(c), it appears § 1626.22(c) was
not brought to the court’s attention in Evans. Thus, Evans has
no bearing on the appropriate level of deference due to the
Commission’s promulgation of § 1601.12(b).

   For these reasons, we hold that the amended charge of dis-
crimination relates back to the filing date of the original
charge and that the EEOC had authority under the ADA to
investigate matters relevant to that charge.

                                     2.

   The Commission also argues that Title VII, not just the
ADA, authorized it to investigate, and thus its authority
encompassed Morrison’s claim that Randstad discriminated
against him on the basis of national origin.8 As explained
above, the original charge, which Randstad concedes was
timely filed, alleged that Morrison was terminated because he
is Jamaican. The amended charge alleged only that the termi-
nation was the result of disability discrimination; it omitted
the allegation of national origin discrimination and replaced
the checkmark for "national origin" discrimination with a
checkmark for "disability" discrimination. The EEOC argues
this omission is immaterial because the original charge was
never "resolved or dismissed" and therefore "continues to
   8
     Randstad argues the Commission forfeited this argument in the district
court, but we disagree. At the hearing on the petition for enforcement, the
Commission clearly contended that both asserted bases of authority were
valid and independent, and that the ADA relation-back theory was only
"one method by which the EEOC would have jurisdiction." J.A. 130; see
also id. ("[E]ven if we discarded the ADA charge, . . . nothing’s been done
to supplant or remove the original Title VII charge."); J.A. 136 (explaining
that as to Title VII, "he’s new to this country, his English is not very good,
that’s why he can’t read and that’s why he was run out by Randstad. The
other amended charge is ADA because it turns out that he does have a dis-
ability.").
                          EEOC v. RANDSTAD                              21
serve as a jurisdictional basis for the subpoena." Appellant’s
Br. at 20. As above, the EEOC’s argument turns on the rea-
sonableness of both its regulations and its interpretation thereof.9

   Under the EEOC’s charge-filing regulations, a charge may
be resolved in one of five ways: if the EEOC (1) makes a
finding of cause; (2) makes a finding of no cause; (3) dis-
misses the charge; or if (4) the charging party withdraws the
charge; or if (5) the parties reach a negotiated settlement. The
first three require that the Commission give notice to the par-
ties. See 29 C.F.R. § 1601.21 (finding of cause); id. § 1601.19
(finding of no cause); id. § 1601.18 (dismissal). Similarly, a
withdrawal or settlement requires the consent of the Commis-
sion. See id. § 1601.10 (withdrawal of charge); id. § 1601.20
(settlement). The EEOC argues that none of these dispositions
occurred; after all, the Commission never gave notice of a
finding of cause, no cause, or dismissal, and never gave con-
sent to a withdrawal or settlement. Rather, it argues, under 29
C.F.R. § 1601.12(b) the "additional information" in Morri-
son’s amended charge was "simply incorporated into the orig-
inal charge," and thus when Morrison amended his charge,
Morrison’s original allegation of national origin discrimina-
tion "remained in place." Appellant’s Br. at 22.

   Section 1601.12(b), the same regulation the Commission
relies upon for its ADA relation-back argument, does not
expressly address the scenario here. It provides in pertinent
part that "[a] charge may be amended to cure technical defects
or omissions, including failure to verify the charge, or to clar-
ify and amplify allegations made therein." 29 C.F.R.
§ 1601.12. The EEOC regulation that governs the withdrawal
  9
    The district court appears to have assumed without deciding that the
amended charge supplemented rather than replaced the original charge.
Nevertheless, it rejected the EEOC’s effort to enforce the subpoena under
Title VII because it concluded the requested materials were irrelevant to
the charge of national origin discrimination. We explain infra why the rel-
evance determination was erroneous, but explain here why the EEOC did
have authority under Title VII.
22                     EEOC v. RANDSTAD
of charges also does not address whether a charging party
who files an amended charge that omits a previously asserted
legal theory has "withdrawn" that portion of the original
charge. See 29 C.F.R. § 1601.10 ("A charge filed by or on
behalf of a person claiming to be aggrieved may be with-
drawn only by the person claiming to be aggrieved and only
with the consent of the Commission.").

    We find the phrase "[a] charge may be amended . . . to clar-
ify and amplify allegations made therein," 29 C.F.R.
§ 1601.12(b), to be ambiguous as applied to the scenario here:
it is consistent with, but does not necessarily require, the con-
clusion that the original charge remained in effect even after
the amended charge sought to "clarify and amplify" the origi-
nal charge. Thus, the dispositive question again becomes
whether the EEOC’s interpretation of § 1601.12(b) is "plainly
erroneous," Auer, 519 U.S. at 461. We easily conclude it is
not. Morrison’s original charge put Randstad on notice that
the EEOC might investigate his allegations of national origin
discrimination. See Sydnor v. Fairfax Cty., Va., 681 F.3d 591,
593 (4th Cir. 2012) (explaining that "requiring a party to file
a charge with the EEOC ensures that the employer is put on
notice of the alleged violations . . . [and] places the resolution
of employment discrimination disputes initially in the hands
of the EEOC") (internal quotation and citation omitted)).
Although upon receiving notice of the amended charge Rand-
stad may have assumed the EEOC’s investigation would
focus instead on the allegation of disability discrimination,
any minimal prejudice (which is all but non-existent) Rand-
stad may have perceived does not render the EEOC’s inter-
pretation of § 1601.12(b) plainly erroneous. The charge-filing
procedure "should not become a tripwire for hapless plain-
tiffs." Sydnor, 681 F.3d at 594.

  For these reasons, the original charge triggered the EEOC’s
investigatory authority under Title VII, and the amended
charge (timely-filed because it related back) triggered its
authority under the ADA. Accordingly, the EEOC had juris-
                      EEOC v. RANDSTAD                       23
diction under both statutes to issue and seek enforcement of
the administrative subpoena.

                              B.

    Once the EEOC has authority to investigate a particular
charge of discrimination, it may access "any evidence of any
person being investigated or proceeded against that relates to
unlawful employment practices covered by this subchapter
and is relevant to the charge under investigation." 42 U.S.C.
§ 2000e-8(a) (emphasis added); see also 42 U.S.C. § 12117(a)
(incorporating 42 U.S.C. § 2000e-8 into the ADA by refer-
ence). The "relevant to the charge" requirement contrasts the
EEOC’s investigatory authority from that of "other federal
agencies that possess plenary authority to demand to see
records relevant to matters within their jurisdiction." Shell
Oil, 466 U.S. at 64. Tellingly, however, a charge of discrimi-
nation "is not the equivalent of a complaint initiating a law-
suit." Id. at 68. Rather, it serves "to place the EEOC on notice
that someone (either a party claiming to be aggrieved or a
Commissioner) believes that an employer has violated the
title." Id.

   Once a charge has placed the Commission on notice that a
particular employer is (or may be) violating Title VII or the
ADA in a particular way, the Commission may access "virtu-
ally any material that might cast light on the allegations
against the employer." Id. at 68-69. This definition of rele-
vance necessarily is broader than "evidentiary relevance"
because in this context "[w]e determine relevancy in terms of
the investigation," EEOC v. Lockheed Martin Corp., Aero &
Naval Systems, 116 F.3d 110, 113 (4th Cir. 1997) (internal
quotation marks omitted), not in terms of litigation of the
merits of the underlying charge. See EEOC v. Konica Minolta
Bus. Solutions U.S.A., Inc., 639 F.3d 366, 369 (7th Cir. 2011)
(analogizing an EEOC investigation to civil discovery under
Fed. R. Civ. P. 26(b)(1), where "[r]elevant," and thereby dis-
coverable, information "need not be admissible at the trial if
24                    EEOC v. RANDSTAD
the discovery appears reasonably calculated to lead to the dis-
covery of admissible evidence"). Congress has delegated to
the EEOC the authority to investigate charges of discrimina-
tion, and naturally the agency has developed expertise in that
area. In this and other areas, where an agency is tasked with
investigation, we "defer to an agency’s own appraisal of what
is relevant so long as it is not obviously wrong." Lockheed
Martin, 116 F.3d at 113 (citing FTC v. Invention Submission
Corp., 965 F.2d 1086, 1089 (D.C. Cir. 1992)). Accordingly,
although "we must be careful" not to render the relevance
requirement "a nullity," it "is not especially constraining,"
Shell Oil, 466 U.S. at 68-69, precisely because we largely
defer to the EEOC’s expertise.

   As noted, the requested materials include information on all
non-administrative positions made by Randstad’s Maryland
offices from 2005 to 2009, including position descriptions and
copies of applications for each position. The question is
whether and to what extent these materials were "relevant" to
the EEOC’s investigation of Morrison’s charges, which
alleged that he had approached only the Hagerstown office for
assignments, and was terminated in September 2006 as the
result of alleged disability and/or national origin discrimina-
tion. The district court concluded that none of the requested
materials were relevant. The district court’s application of an
unduly strict standard of relevance amounted to legal error,
leading to an abuse of discretion. Applying the correct stan-
dard, with deference to the EEOC’s assessment of relevance,
we conclude that all of the EEOC’s requested materials fall
within the broad definition of relevance applicable to EEOC
administrative subpoenas.

                              1.

  As for Morrison’s charge of national origin discrimination,
the EEOC argues the requested materials are relevant as fol-
lows:
                     EEOC v. RANDSTAD                        25
    The information requested in items 3 and 4 will
    assist the EEOC in determining whether Randstad
    imposes a literacy requirement that discriminates on
    the basis of national origin. Knowing the types of
    non-clerical jobs into which Randstad has placed
    individuals since January 2005, the year Morrison
    first sought work through Randstad, will assist the
    EEOC in ascertaining whether Randstad is correct
    when it claims that an ability to read is needed to
    perform all of its laborer positions, or whether Rand-
    stad has made other placements—like the Good
    Humor job Morrison did in September 2005—that
    can be performed successfully even without an abil-
    ity to read. This information, in turn, will help the
    EEOC determine whether Randstad’s professed liter-
    acy requirement eliminates from consideration indi-
    viduals who could perform the jobs in question but
    are nevertheless excluded simply because they can-
    not read and write English because their national ori-
    gin is somewhere other than the United States and
    their native language is not English.

Appellant’s Br. at 37-38. This "appraisal of what is relevant
. . . . is not obviously wrong," Lockheed Martin, 116 F.3d at
113, because the requested information "might cast light on
[Morrison’s] allegations" of national origin discrimination,
Shell Oil, 466 U.S. at 69. Accordingly, we defer to the
EEOC’s assessment of relevance.

   The district court rejected the argument that the requested
materials were relevant to Morrison’s charge of national ori-
gin discrimination because it disbelieved one premise of the
Commission’s relevance argument, namely, that someone
from Jamaica might be less proficient in English because he
is from Jamaica. That is, the court discerned no factual nexus
between Morrison’s Jamaican origin and his illiteracy, appar-
ently because although some people in Jamaica speak the lan-
guage Patois, English is also predominant. See J.A. 134
26                    EEOC v. RANDSTAD
(observing that although in Jamaica "there is what is known
as Patois spoken by other members of the community there,
sometimes those with lesser education," "English is clearly
spoken in Kingston and in Montego Bay").

   At the subpoena-enforcement stage, however, "any effort
by the court to assess the likelihood that the Commission
would be able to prove the claims made in the charge would
be reversible error." Shell Oil, 466 U.S. at 72 n.26. The
EEOC’s authority to investigate "is not negated simply
because the party under investigation may have a valid
defense to a later suit." EEOC v. United Air Lines, Inc., 287
F.3d 643, 651 (7th Cir. 2002). Although there may sometimes
be a fine line between, on the one hand, assessing the rele-
vance of requested information to a charging party’s allega-
tions and, on the other hand, "determin[ing] whether the
charge of discrimination is ‘well founded’ or ‘verifiable,’"
Shell Oil, 466 U.S. at 72 n.26, we conclude that the district
court’s rejection of the EEOC’s alleged factual nexus crossed
the line into an assessment of the merits of Morrison’s claim.
The effect of inquiring into the merits was essentially to "re-
quire[ ] the EEOC to make a reasonable cause showing as a
prerequisite to enforcement of the [subpoena]." Graniteville
Co. v. EEOC, 438 F.2d 32, 36 (4th Cir. 1971). This served
"not only to place the cart before the horse, but to substitute
a different driver [the district court] for the one appointed by
Congress [the EEOC]." Id.; see also EEOC v. Dillon Cos.,
Inc., 310 F.3d 1271, 1277 (10th Cir. 2002) ("We will not . . .
either encourage or allow an employer to turn a summary
subpoena-enforcement proceeding into a mini-trial by allow-
ing it to interpose defenses that are more properly addressed
at trial."). The EEOC has satisfied the relevancy requirement
as to the Title VII charge.

                               2.

   The EEOC argues the requested materials are also relevant
to the charge of disability discrimination, as it explains:
                          EEOC v. RANDSTAD                              27
       Randstad terminated Morrison’s employment
       because the company concluded that absent an abil-
       ity to read—a condition that, in Morrison, may be
       the result of an intellectual impairment—Morrison is
       unable to perform any job for any Randstad’s cus-
       tomer. The EEOC already possesses information that
       undermines Randstad’s claim: Morrison was unable
       to read English when he worked for Randstad in
       2005, but he nevertheless successfully completed a
       monthlong assignment at Good Humor, belying
       Randstad’s claim that English literacy skills are nec-
       essary for successful performance of all its laborer
       positions. The information requested in subpoena
       items 3 and 4 is relevant to this investigation because
       it will permit the EEOC to determine whether Rand-
       stad’s Maryland branches made any other staffing
       placements into jobs, like the Good Humor assign-
       ment, that a person who lacks English literacy skills
       because of a disability could nevertheless perform.

Appellant’s Br. at 39. The district court rejected the EEOC’s
relevance argument because, in the court’s view, the only
materials relevant to the EEOC’s investigation were those
pertaining to the four specific placements to which Morrison
was himself assigned; information on other positions were
beyond the scope of the EEOC’s investigatory authority.10
  10
     Although the district court did not expressly state its reasoning in
those terms, we conclude this must have been the district court’s implicit
premise. The court stated that the requested materials were not relevant to
Morrison’s disability discrimination charge because "Morrison solely
sought employment by Randstad in its Hagerstown office, and was only
employed by Randstad from August 2005 until September 2006." Rand-
stad, 765 F. Supp. 2d at 742. Although it would seem to follow from that
observation that information on position assignments made by the Hagers-
town office in 2005-2006 would be relevant to Morrison’s charge, the dis-
trict court nonetheless concluded that none of the information the EEOC
was seeking was relevant to Morrison’s charge. Id. Therefore, the district
court apparently reasoned that information on position assignments to
which Morrison was not assigned was irrelevant to the EEOC’s investiga-
tion.
28                        EEOC v. RANDSTAD
The district court’s analysis does not square with the deferen-
tial standard of relevance the Supreme Court applied in Shell
Oil.

   As discussed above, during an investigation of a charge that
a particular employer discriminated in a particular way, the
Commission is entitled to access "virtually any material that
might cast light on the allegations." Shell Oil, 466 U.S. at 68-
69. Here, the EEOC has determined that information on posi-
tions other than those held by Morrison "might cast light" on
his allegations of disability discrimination because it will
allow the Commission to "test Randstad’s assertion that all of
its warehouse and laborer positions require basic literacy
skills." Appellant’s Br. at 40. If it turns out Randstad’s asser-
tion that all of its positions require literacy is unsupported by
the requested materials, then those materials might turn out to
constitute evidence of unlawful discrimination. Accordingly,
information on at least some positions other than those held
by Morrison is relevant to the EEOC’s investigation.11

   This raises the somewhat closer question of whether the
EEOC overstepped in its assessment of how many other non-
administrative position assignments were relevant to its inves-
tigation of Morrison’s charge. Although the EEOC originally
requested information for position assignments nationally, it
later narrowed its request to Randstad’s Maryland offices, for
the years 2005 to 2009. Randstad argues in essence that, even
if some position assignments beyond those Morrison held are
relevant, the geographic and temporal scope of the subpoena
goes too far, and we should at minimum limit the subpoena
to position assignments made by the Hagerstown office dur-
  11
     We recognize that in Shell Oil the charge at issue was a Commission-
er’s charge that alleged a pattern or practice of discrimination, see 466
U.S. at 67, and thus the scope of the EEOC’s investigation arguably may
have been broader than the permissible scope of its investigation here. But
that factual distinction does not undercut the Court’s clear instruction to,
in general, defer to the EEOC’s assessment of what materials are relevant
to its investigation.
                      EEOC v. RANDSTAD                       29
ing the years 2005 and 2006, the years during which Morrison
was temporarily employed by Randstad. We disagree. Again,
we and the district court must defer to the EEOC’s appraisal
of what is relevant so long as it is not obviously wrong. Lock-
heed Martin, 116 F.3d at 113. We conclude the thirteen-
office, five-year scope of the subpoena was not an unreason-
able exercise of the EEOC’s discretion in deciding how to
investigate whether Randstad’s literacy policy was discrimi-
natory. Although Randstad is correct that the EEOC must
have "a realistic expectation rather than an idle hope that
something may be discovered," United Air Lines, 287 F.3d at
653, we do not believe, as Randstad argues, that "the EEOC
has demonstrated nothing more than ‘an idle hope that some-
thing may be discovered.’" Appellee’s Br. at 33. For these
reasons, the requested materials are relevant to the EEOC’s
investigation.

                              C.

   The Commission’s showing of relevance does not end the
inquiry. Even if the requested materials are relevant to a
charge of discrimination, Randstad is entitled to attempt to
show that compliance with the subpoena would be "unduly
burdensome." Maryland Cup, 785 F.2d at 477. "The burden
of proving that an administrative subpoena is unduly burden-
some is not easily met." Id. "The party subject to the sub-
poena must show that producing the documents would
seriously disrupt its normal business operations." Id. Although
"[w]hat is unduly burdensome depends on the particular facts
of each case and no hard and fast rule can be applied to
resolve the question," United Air Lines, 287 F.3d at 653, an
important factor is the cost of production "in the light of the
company’s normal operating costs." Maryland Cup, 785 F.2d
at 479.

   Here, Randstad’s "evidence" of burdensomeness was lim-
ited to an affidavit from its Director of IT Applications repre-
senting that gathering the information would take three
30                    EEOC v. RANDSTAD
Randstad employees at least 40 hours each, at a total esti-
mated labor cost of $14,000 to $19,000. The district court
seemingly relied on this estimate and found that Randstad had
established that compliance would impose an undue burden.
Randstad, 765 F. Supp. 2d at 742. On appeal, the EEOC
argues the affidavit is insufficient as a matter of law under
Maryland Cup. We agree with the EEOC.

   The EEOC subpoena in Maryland Cup requested, among
other things, that the employer provide a list of the race of
former employees. 785 F. 2d at 478. Gathering that informa-
tion required the company to interview the supervisors and
coworkers of former employees, which Maryland Cup
asserted would cost $75,000 (in 1985 dollars), a cost that
Maryland Cup argued was unduly burdensome. Id. at 479. We
rejected that argument because the employer had failed to
show either that gathering this information was "unduly bur-
densome in the light of the company’s normal operating
costs," or that gathering the information would "threaten" or
"seriously disrupt" its "normal business operations." Id. at
477, 479. Accordingly, we vacated the district court’s denial
of the EEOC’s petition and instructed the court to enforce the
subpoena ("except insofar as it require[d] the company to
retrieve evidence from persons no longer under its control").
Id. at 479.

   We reach a like conclusion here. Randstad’s affidavit on
burdensomeness asserted only that compiling the requested
information would require three employees to spend 40 hours
each, at a total cost $14,000 to $19,000. Randstad did not
proffer evidence of its "normal operating costs," and the dis-
trict court made no such findings. Randstad also did not
assert, and the district court did not find, that gathering the
requested information would "threaten" or "seriously disrupt"
Randstad’s business operations. In these circumstances, we
conclude that the evidence proffered by Randstad was insuffi-
                         EEOC v. RANDSTAD                              31
cient as a matter of law to support a finding that the costs of
compliance rise to the level of an undue burden.12

                                   III.

   For the foregoing reasons, we reverse and remand for entry
of an order granting the EEOC’s application for enforcement.

                                   REVERSED AND REMANDED




  12
     As an alternative argument, the EEOC argues the district court com-
mitted clear factual error in finding Randstad’s cost estimate to be accu-
rate. See Appellant’s Br. at 42 n.9; see also supra p. 10. Because we find
Randstad’s evidence was insufficient as a matter of law, we need not
decide whether there was clear error in this regard.
