 United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT



Argued November 17, 2011           Decided January 17, 2012

                        No. 10-5419

                     GARY HAMILTON,
                       APPELLANT

                             v.

 TIMOTHY F. GEITHNER, SECRETARY OF THE UNITED STATES
                      TREASURY,
                       APPELLEE


        Appeal from the United States District Court
                for the District of Columbia
                    (No. 1:05-cv-01549)


    David A. Branch argued the cause and filed the briefs for
appellant.

    Jeremy S. Simon, Assistant U.S. Attorney, argued the
cause for appellee. With him on the brief were Ronald C.
Machen Jr., U.S. Attorney, and R. Craig Lawrence, Assistant
U.S. Attorney.

    Before: TATEL and GARLAND, Circuit Judges, and
GINSBURG, Senior Circuit Judge.

    Opinion for the Court filed by Circuit Judge TATEL.
                              2
     TATEL, Circuit Judge: Appellant, an employee of the
Internal Revenue Service, alleges that the Service
discriminated against him on the basis of race and gender
when it awarded a temporary detail and then a permanent
promotion to a white female employee. Appellant also claims
that the IRS retaliated against him when he pursued the matter
with its Equal Employment Opportunity office. The district
court granted summary judgment to the government on all
three claims. We agree that appellant failed to exhaust his
claim regarding the temporary detail and so affirm that
portion of the district court’s judgment. But because we
conclude that a reasonable jury could find that the
government’s proffered nondiscriminatory reason for denying
appellant the permanent promotion was pretextual and that
discrimination was the real reason, we reverse the grant of
summary judgment on the discriminatory promotion claim
and remand to allow that claim to proceed to trial. And
because we conclude that appellant established a prima facie
case of retaliation, we remand that claim for further
proceedings consistent with this opinion.

                              I.
     Gary Hamilton, an African American man, has served as
an industrial hygienist in the federal government for much of
his career. After earning a bachelor’s degree in industrial
hygiene and a master’s degree in public health, Hamilton
spent approximately fifteen years as an Industrial Hygienist
for the Navy and the Department of Defense, a GS-13 grade
position under the federal government’s General Schedule
pay scale. In October 2001, when Hamilton’s position was
relocated to another city, he accepted employment as a GS-12
Industrial Hygienist within the IRS’s Real Estate and
Facilities Management department.
                              3
     About a year-and-a-half later, the IRS announced a
vacancy for a GS-14 “Safety Specialist (Safety/
Occup[ational] Health Manager)” position, which we shall
refer to as the Safety Manager position. In May 2003,
Hamilton applied for that position, as did other IRS
employees. Paul Carroll, an IRS program analyst, ranked the
candidates based upon knowledge, skills, and abilities (KSA)
criteria provided to him by IRS personnel staff. Based on
Carroll’s rankings, personnel staff selected the four highest-
scoring candidates for the “best qualified” list, including
Hamilton, Annette Burrell (a white female), Camille
Carraway (a white female), and Michael Perkins (a white
male). Of these, Hamilton, Burrell, and Caraway had each
received the highest possible KSA ranking score of 25, while
Perkins had received a score of 19. The four candidates were
interviewed by a three-member panel consisting of “selecting
official” Stuart Burns (a white male), Mike Huston (a white
male), and Tatika Mitchell (an African American female).
Although panel members took notes during the interviews,
they neither rated nor scored the applicants. In July 2003,
Burns selected Annette Burrell for the position.

     Hamilton learned of Burrell’s selection sometime in
August. He also discovered that one year earlier, in August
2002, Burrell had received a temporary detail assignment as a
GS-14 Management Analyst/National Safety and Health
Project Manager, a position Hamilton claims was expressly
designed to qualify Burrell for the Safety Manager position.
Shortly thereafter, Hamilton contacted the IRS’s Equal
Employment Opportunity (EEO) office for a counseling
session, in which he claimed that IRS officials acted with a
discriminatory motive in (1) selecting Burrell, a
“demonstrably” less-qualified white female, for the Safety
Manager position; (2) affording Burrell preferential treatment
by “giving [her] a detail (for 12 months) into the position”;
                              4
and (3) using a subjective evaluation process to create a
legitimate explanation for its discriminatory selection. EEO
Counseling Report at 2; see also 29 C.F.R. § 1614.105(a)
(requiring aggrieved persons to “consult a Counselor prior to
filing a complaint in order to try to informally resolve the
matter”). On October 21, 2003, Hamilton filed a formal EEO
complaint alleging that IRS selecting officials discriminated
against him on the basis of gender and race by “select[ing] a
Caucasian female with observably and vastly inferior
qualifications” for the Safety Manager position. EEO Compl.
at 2. Later, in January 2004, Hamilton learned that Burns had
detailed Camille Carraway—the other white female
interviewed for the Safety Manager position—to a temporary
GS-14 Safety Manager position, prompting Hamilton to file
another EEO complaint, this one alleging discrimination and
retaliation in the decision to award the detail to Carraway.

     When the EEO failed to take any action within 180 days
from the filing of Hamilton’s complaint, see 29 C.F.R.
§ 1614.407(b) (authorizing civil actions if no final action is
taken within 180 days after a complaint is filed), Hamilton
sued the Treasury Secretary in the United States District
Court for the District of Columbia. In his original complaint,
Hamilton asserted two claims under Title VII of the Civil
Rights Act of 1964, 42 U.S.C. §§ 2000e et seq.: that the 2003
selection of Annette Burrell over Hamilton for the Safety
Manager position was motivated by race- and gender-based
discrimination (the “discriminatory promotion claim”), and
that the 2004 selection of Camille Carraway for the Safety
Manager detail amounted to retaliation in response to
Hamilton’s EEO filing (the “retaliation claim”). Hamilton
subsequently amended his complaint to assert a third claim
alleging that the 2002 selection of Burrell for a temporary GS-
14 Management Analyst detail was discriminatory and a
                                5
prohibited personnel practice in violation of the Civil Service
Reform Act, 5 U.S.C. § 2302 (the “detail claim”).

     The Secretary moved for summary judgment on all
claims. As to Hamilton’s discriminatory promotion claim, the
Secretary, though conceding that Hamilton had established a
prima facie case of discrimination, claimed that the IRS had a
legitimate, nondiscriminatory reason for promoting Burrell
over Hamilton, namely, that Hamilton did not perform as well
as Burrell in the interview. In considering Hamilton’s
argument that this proffered nondiscriminatory reason was
pretextual, the district court first addressed his claim that the
“inexplicable gulf between the credentials of [Hamilton] and
Burrell” was “inherently indicative of discrimination.”
Hamilton v. Paulson, 542 F. Supp. 2d 37, 44 (D.D.C. 2008)
(“Hamilton I”) (internal quotation marks omitted). Although
acknowledging that Hamilton’s “superior educational
credentials and experience as an industrial hygienist suggests
that he may have had a stronger grasp of the technical aspects
of occupational safety,” the court observed that Burrell’s
“considerable experience in developing safety management
programs at a national level” indicated that she might have
been “better equipped” for other aspects of the position. Id. at
47. After reviewing the two candidates’ relevant experience,
and noting that each had received perfect KSA scores, the
court found “no factual basis whatsoever for a jury to
conclude that there are disparities in the relative qualifications
of the plaintiff and Burrell” significant enough to support an
inference of discrimination. Id. The court then reviewed
Hamilton’s allegations that the selection process suffered
from numerous irregularities, that the IRS had destroyed
evidence, that inconsistencies undermined its evidence, and
that it exhibited a pattern of promoting white females over
African Americans. As to each of these claims, the court
found that Hamilton’s allegations either lacked support in the
                                6
record or suggested no bias. Id. at 48–57. “Nothing in the
record,” the district court concluded, “would permit a
reasonable jury to infer that the defendant’s explanation . . . is
in any way a pretext for discrimination.” Id. at 57.
Accordingly, the court granted summary judgment to the
Secretary on Hamilton’s discriminatory promotion claim.

     The district court also granted summary judgment to the
government on Hamilton’s retaliation claim. Id. at 61. The
court found that Hamilton had failed to establish a prima facie
case because he had shown no causal connection between his
statutorily protected EEO activity and the selection of
Carraway for the 2004 Safety Manager detail. Observing that
although a plaintiff may establish causation by showing that
the defendant “had knowledge of his protected activity and
that the adverse personnel action took place shortly after that
activity,” the court pointed out that district courts in this
circuit generally follow an informal “three-month rule” for
cases in which a plaintiff attempts to establish a prima facie
case of retaliation based on temporal proximity alone. Id. at
58 (quotation and alterations omitted). Measuring temporal
proximity based solely on Hamilton’s first protected
activity—the August 2003 EEO counseling session—the
district court concluded that the five- to six-month gap
between that session and the January 2004 Carraway selection
precluded Hamilton from establishing causation based on
temporal proximity alone. In so concluding, the district court
rejected Hamilton’s argument that the time period between his
protected activity and the adverse employment action should
be measured from October 2003, when he filed his EEO
complaint, and that Burns had engaged in a “pattern of
antagonism” against Hamilton in the months leading up to
Carraway’s selection. Id. at 58–61.
                               7
     In a later ruling, the district court granted summary
judgment to the Secretary on Hamilton’s 2002 detail claim.
According to the district court, Hamilton had failed to exhaust
his administrative remedies as required by both Title VII and
the Civil Service Reform Act. Hamilton v. Geithner, 743 F.
Supp. 2d 1, 13–14 (D.D.C. 2010) (“Hamilton II”).

    Hamilton now appeals, and we review the district court’s
grant of summary judgment de novo. Jones v. Bernanke, 557
F.3d 670, 674 (D.C. Cir. 2009).

                              II.
     We begin with Hamilton’s claim that the 2002 selection
of Burrell for a temporary GS-14 detail violated both Title VII
and the Civil Service Reform Act. Government employees
alleging discrimination in violation of Title VII or challenging
personnel practices prohibited by the Civil Service Reform
Act must exhaust administrative remedies before bringing
their claims to federal court. See Payne v. Salazar, 619 F.3d
56, 65 (D.C. Cir. 2010) (“Title VII complainants must timely
exhaust their administrative remedies before bringing their
claims to court.” (internal quotation marks and alterations
omitted)); Weaver v. U.S. Info. Agency, 87 F.3d 1429, 1433
(D.C. Cir. 1996) (“Under the [Civil Service Reform Act],
exhaustion of administrative remedies is a jurisdictional
prerequisite to suit.”). Because Hamilton’s 2002 detail claim
presented a “mixed case,” involving charges of both
discrimination and prohibited personnel practices, Hamilton
could have exhausted his administrative remedies by
presenting his claim either to the IRS’s EEO office or to the
Merit Systems Protection Board. Butler v. West, 164 F.3d
634, 638 (D.C. Cir. 1999) (“An employee who intends to
pursue a mixed case . . . can choose between filing a ‘mixed
case complaint’ with her agency’s EEO office and filing a
                                8
‘mixed case appeal’ directly with the MSPB.”). As the district
court found, however, Hamilton did neither.

     Hamilton has never claimed that he sought review before
the Merit Systems Protection Board, insisting instead that he
exhausted his detail claim before the IRS’s EEO Office. But
Hamilton’s formal EEO complaint makes no mention of the
2002 detail. Instead, the complaint identifies only the 2003
Safety Manager selection as the alleged discriminatory action.
Indeed, it describes that selection decision quite specifically,
providing both the position title and vacancy announcement
number. Moreover, in a follow-up letter to Hamilton, the EEO
office identified the claim to be investigated as whether
Hamilton had been discriminated against “when he was not
selected on August 11, 2003, for promotion to the position of
Safety and Health Manager, GS-0018-14, under Vacancy
Announcement Number 15-02-OFM03706.” Letter from Jerry
Armstrong, Dir., Treasury Compl. Ctr., to Howard Wallace,
Designated Representative for Gary Hamilton (Dec. 17,
2003). The letter goes on to state: “If you disagree with the
claim, please notify me in writing within 15 days of the date
of the letter. . . . If no response is received, I will assume that
you agree with the claim(s) and will proceed with the
investigation of the complaint.” Id. Hamilton neither
responded to this letter nor “amend[ed] [his] complaint at any
time prior to the conclusion of the investigation,” 29 C.F.R.
§ 1614.106(d), to include the 2002 detail claim.

    Hamilton nonetheless argues that he satisfied the
exhaustion requirement by presenting his detail claim to the
IRS during his August 2003 EEO counseling session,
approximately two months before he filed his formal EEO
complaint. In support, he cites the EEO counseling report,
pointing out that it lists the 2002 detail as part of the basis for
his discrimination claim. See EEO Counseling Report at 2
                               9
(describing Hamilton’s allegation that IRS “[p]lanned,
arranged and executed with a discriminatory motive to give
[Burrell] preferential treatment by giving a detail (for 12
months) into the [Safety Manager] position”). But this does
not help Hamilton. Filing a formal complaint is a prerequisite
to exhaustion, see 29 C.F.R. § 1614.407 (“A complainant who
has filed an individual complaint . . . is authorized under title
VII . . . to file a civil action in an appropriate United States
District Court” after final EEO action or after 180 days
(emphasis added)), so Hamilton cannot rely on the EEO
counseling report to establish exhaustion of a claim that he
failed to include in his formal complaint.

     According to Hamilton, however, the government has
waived its exhaustion defense. But Hamilton’s first argument
in support of this proposition—that the IRS “waived”
exhaustion by accepting and then dismissing his detail claim
without proper notice—fails because his formal EEO
complaint omitted the detail claim. See 29 C.F.R.
§ 1614.107(b) (“Where the agency believes that some but not
all of the claims in a complaint should be dismissed . . . the
agency shall notify the complainant in writing of its
determination[.]” (emphasis added)). His second argument—
that the Secretary waived the defense in the district court—
likewise fails because the Secretary not only raised exhaustion
as an affirmative defense in his answer, but also moved to
dismiss on exhaustion grounds after Hamilton asserted the
detail claim in his amended complaint. We shall therefore
affirm the district court’s dismissal of Hamilton’s detail claim
for failure to exhaust administrative remedies and turn our
attention to the two claims properly before us.

                              III.
   In support of his promotion discrimination claim,
Hamilton argues that the Secretary’s proffered reason for
                               10
denying him the GS-14 Safety Manager promotion—that
Hamilton “ ‘did not perform well in his interview . . . as
compared to [Burrell’s] performance,’ ” Hamilton I, 542 F.
Supp. 2d at 43 (quoting Def.’s Mem. at 7)—was pretext for
discrimination. According to Hamilton, the district court erred
in granting summary judgment on this claim because a
reasonable jury could infer discrimination based on evidence
of (1) Hamilton’s superior qualifications for the Safety
Manager position, (2) the highly subjective nature of the
government’s reasons for not hiring Hamilton, and (3)
procedural irregularities in the selection process.

     Where, as here, the employer claims a legitimate, non-
discriminatory explanation for its decision to promote one
employee over another, the “one central inquiry” on summary
judgment is “whether the plaintiff produced sufficient
evidence for a reasonable jury to find that the employer’s
asserted non-discriminatory reason was not the actual reason
and that the employer intentionally discriminated against the
plaintiff on a prohibited basis.” Adeyemi v. District of
Columbia, 525 F.3d 1222, 1226 (D.C. Cir. 2008). We
consider this question “in light of the total circumstances of
the case,” asking “whether the jury could infer discrimination
from the combination of (1) the plaintiff's prima facie case;
(2) any evidence the plaintiff presents to attack the
employer’s proffered explanation for its actions; and (3) any
further evidence of discrimination that may be available to the
plaintiff . . . or any contrary evidence that may be available to
the employer.” Aka v. Wash. Hosp. Ctr., 156 F.3d 1284, 1289,
1291 (D.C. Cir. 1998) (en banc). Because in appropriate cases
a “factfinder’s disbelief of the reasons put forward by the
defendant” may support an inference of intentional
discrimination, St. Mary’s Honor Ctr. v. Hicks, 509 U.S. 502,
511 (1993), we do not routinely require plaintiffs “to submit
evidence over and above rebutting the employer’s stated
                               11
explanation in order to avoid summary judgment.” Aka, 156
F.3d at 1290. In reviewing the district court’s grant of
summary judgment, moreover, we view the evidence in the
light most favorable to Hamilton and draw all reasonable
inferences in his favor, taking care neither to make credibility
determinations nor weigh the evidence before us. Jones, 557
F.3d at 674, 681. Ultimately, we may affirm the district
court’s judgment only if we are able to conclude that no
reasonable jury could reach a verdict in Hamilton’s favor. Id.
at 674.

     Although Hamilton relies on a wide range of evidence to
attack the Secretary’s proffered nondiscriminatory
explanation, the parties’ briefs focus first and foremost on the
evidence of Hamilton’s and Burrell’s qualifications, so we
shall begin there as well. The Supreme Court has held that
“qualifications evidence may suffice, at least in some
circumstances,” to show that an employer’s proffered
explanation is pretext for discrimination. Ash v. Tyson Foods,
Inc., 546 U.S. 454, 457 (2006). Although the Court has
declined to define “precisely what standard should govern,”
id., our cases have developed a framework for evaluating
claims “involving a comparison of the plaintiff’s
qualifications and those of the successful candidate.” Aka, 156
F.3d at 1294. Pursuant to our decision in Aka v. Washington
Hospital Center, “[i]f a factfinder can conclude that a
reasonable employer would have found the plaintiff to be
significantly better qualified for the job, but this employer did
not, the factfinder can legitimately infer that the employer
consciously selected a less-qualified candidate—something
that employers do not usually do, unless some other strong
consideration, such as discrimination, enters into the picture.”
Id. That said, “we must assume that a reasonable juror who
might disagree with the employer’s decision, but would find
the question close, would not usually infer discrimination on
                              12
the basis of a comparison of qualifications alone.” Id. For this
reason, a disparity in qualifications, standing alone, can
support an inference of discrimination only when the
qualifications gap is “great enough to be inherently indicative
of discrimination”—that is, when the plaintiff is “markedly
more qualified,” “substantially more qualified,” or
“significantly better qualified” than the successful candidate.
Holcomb v. Powell, 433 F.3d 889, 897 (D.C. Cir. 2006)
(internal quotation marks omitted).

     Applying this standard here, we believe, as explained in
detail below, that a jury confronted with the record evidence
could find that Hamilton had far more formal training and
education than Burrell, significantly greater technical
expertise, and broader experience developing and managing
complex safety programs. Whether this evidence would be
sufficient to allow such a jury to find Hamilton “significantly”
or “markedly” more qualified than Burrell, Holcomb, 433
F.3d at 897, and thus to infer discrimination based on
qualifications evidence alone, presents a relatively close
question. Given the record in this case, however, it is a
question we need not conclusively resolve. Our task is to
“review the record taken as a whole,” Reeves v. Sanderson
Plumbing Prods., Inc., 530 U.S. 133, 150 (2000) (internal
quotation marks omitted), and plaintiffs are “expressly not
limited to comparing [their] qualifications against those of the
successful applicant; [they] may seek to expose other flaws in
the employer’s explanation.” Holcomb, 433 F.3d at 897; see
also Ash, 546 U.S. at 458 (noting approvingly the Eleventh
Circuit’s suggestion that “superior qualifications may be
probative of pretext when combined with other evidence”).
Here, Hamilton relies not only on comparative qualifications
evidence, but also “seek[s] to expose,” Holcomb, 433 F.3d at
897, procedural irregularities in a highly subjective selection
process. Reviewing the record as a whole, we agree that the
                              13
evidence of Hamilton’s superior qualifications taken together
with “other flaws in the employer’s explanation,” id., creates
a genuine issue of material fact that only a jury can resolve.

     The qualifications evidence includes the position
description, the candidates’ applications, Hamilton’s
declaration, and Burrell’s deposition testimony. According to
the position description, the GS-14 Safety Manager position
“provides senior analytical support to management in
assessing and defining the needs of the Agency for
implementation and evaluation of IRS Safety Program.”
Position Description at 2. The position requires a mix of
technical and policy expertise, including “[e]xpert level
knowledge of and extensive experience in the theories,
principles, practices and advances pertaining to safety and
occupational health disciplines and administration.” Id. The
position description lists the Safety Manager’s four major
duties: (1) developing policies, procedures, and standards for
the IRS Safety Program and providing technical guidance to
protect IRS personnel and property “from the full spectrum of
intentional and non-intentional human threats, as well as man-
made and natural disasters”; (2) advising “top management on
the most complex safety matters,” including budgetary and
resource-distribution issues related to safety; (3) interpreting
national safety directives, formulating broad policy direction,
and preparing policy and program statements for senior
management; and (4) serving both as a “top liaison” to other
government agencies and as a “technical authority” on novel
safety issues. Id. Although focusing primarily on the required
technical expertise and safety policy experience, the position
description also states that the Safety Manager position
involves “[f]requent, extensive personal contacts . . . with top
levels of management and staff . . . . to defend, promulgate,
secure, and gain compliance with the Service’s Safety
Program.” Id. at 3.
                               14
     When Hamilton applied for the position in May 2003, he
had approximately nineteen years of experience working in
industrial hygienist and safety professional positions within
the federal government, including approximately fifteen years
as a GS-13 Industrial Hygienist with the Navy and
Department of Defense and nearly two years as a GS-12
Industrial Hygienist with the IRS. Hamilton has a bachelor’s
degree in industrial hygiene (defined as “the science of
anticipating, recognizing, evaluating, and controlling
workplace conditions that may cause workers’ injury or
illness,” Occupational Safety & Health Admin., Informational
Booklet on Industrial Hygiene (1998), available at
http://www.osha.gov/Publications/OSHA3143/
OSHA3143.htm), as well as a master’s degree in public health
with a specialty in environmental and occupational health.
Hamilton has been certified by the American Board of
Industrial Hygiene since 1995, and he completed a master’s
level Senior Executive Leadership Training program for the
federal government sector in 2000.

     By contrast, Burrell has no college degree and little
formal training in occupational safety. Her knowledge of
safety practice and policy comes mostly from on-the-job
training, as well as one forty-hour OSHA class and a few two-
to three-day courses on indoor air quality, electrical standards,
and principles of industrial hygiene. In comparison to
Hamilton’s nineteen consecutive years of service as an
industrial hygienist, Burrell had approximately eight years of
substantive safety experience at the time of her application,
much of it prior to 1997. Specifically, she worked for
approximately four years as a GS-11 Program
Analyst/Regional Safety Officer (1990–1994), two-and-a-half
years as a GS-12 Safety and Occupational Health Manager
(1994–1997), and less than one year on a temporary detail as
a GS-14 National Safety and Health Project Manager (2002–
                               15
2003). During the more than five years between April 1997,
when she left her GS-12 Safety and Occupational Health
Manager position, and August 2002, when she began her
temporary detail, Burrell appears to have had little contact
with the safety field, having transferred first to a position as a
Space Acquisition Specialist (1997–2000) and then to a Client
Services Specialist position (2000–2002). Perhaps because of
Burrell’s less extensive training and experience, selecting
official Burns stated that she “was not as qualified as
[Hamilton] in the technical aspects of industrial hygiene and
safety.” Burns Decl. at 3. The district court agreed, finding
that Hamilton’s “superior educational credentials and
experience as an industrial hygienist suggest[] that he may
have had a stronger grasp of the technical aspects of
occupational safety.” Hamilton I, 542 F. Supp. 2d at 47.

     In addition to Hamilton’s superior technical expertise, he
possessed wide-ranging experience in developing safety
policies and managing complex, large-scale safety programs.
While working at the Defense Department, for instance,
Hamilton managed the Department’s Worker Safety Pilot
Program, a large project that involved analyzing private-
sector safety programs, implementing and evaluating pilot
programs at different military sites, integrating budgeting and
fiscal planning with safety program development, and
preparing a final report to Congress. In that position,
Hamilton also served as the point of contact for the
administration of a memorandum of understanding between
the Assistant Secretary of Defense and the Deputy Under
Secretary, and communicated with senior Defense
Department program officers to coordinate safety and health
policy across military departments. Similarly, while working
for the Navy, Hamilton managed its Hazard Abatement
Program, leading a group of forty base safety managers,
playing a leadership role in setting mission priorities for all
                              16
Navy divisions, and managing a $4.5 million budget. Finally,
during his most recent IRS assignment, Hamilton’s
responsibilities included conducting resource assessments,
developing budgets, managing safety inspectors, and
developing and writing policy. He also developed the first
standard operating procedure for the Service’s semi-annual
safety inspections and created a database program “capable of
inputting, retrieving, and reporting specific safety inspection
data.” Hamilton Appl. Given this extensive, detailed, and
concrete evidence of Hamilton’s safety policy and program
experience, a reasonable jury could easily find him well-
positioned to perform the “extremely complex and significant
functions in the development of [safety] decisions and
policies,” Position Description at 2, required by the Safety
Manager position.

     To be sure, Burrell also has experience in safety policy
and project management. In her application for the Safety
Manager position, she states that as a GS-12 Safety and
Occupational Health Manager, she “[d]eveloped policies and
procedures for use Servicewide . . . to enable regions to
implement programs,” designed a nationwide safety
management system for use in analyzing data and identifying
safety-related trends, and “was responsible for setting regional
and national policy and program direction.” Burrell Appl.
Burrell also revitalized Atlanta’s Federal Safety and Health
Council, a task requiring that she establish an alliance
between the IRS and OSHA. Finally, during her detail as
National Safety and Health project manager, Burrell played a
key role in developing a National Concept of Operations for
IRS’s National Safety and Health Program, id., acting as
project leader and bringing in various stakeholders to develop
safety procedures.
                              17
       That said, the Secretary’s evidence that Burrell actually
formulated policies or provided guidance “on the most
complex safety matters,” Position Description at 2, is
comparatively thin. While Burrell may have gained some
safety policy experience during her two-and-a-half years as a
GS-12 Safety and Occupational Health Manager, the record
contains scant evidence of specific policies or programs that
Burrell herself developed. See Burrell Appl. (stating only in
general terms that she “[d]eveloped policies and procedures
for use Servicewide to regional staffs to enable regions to
implement programs” and “was responsible for setting
regional and national policy and program direction”).
Moreover, a jury could find that Burrell’s recent detail
focused significantly more on planning activities and
“ensur[ing] buy-in” from stakeholders than on formulating
safety policy or providing advice on complex safety matters.
See Burrell Appl. (describing her work as “plan[ing]
numerous activities associated with the reengineering” of the
safety program, leading a working group with business unit
representatives to “ensure buy-in,” developing “action plans
. . . to ensure that each [business stakeholder] had a chance to
comment on the Vision of the new Safety and Health
program,” and holding monthly meetings with stakeholder
points of contact to address concerns and provide
consultations). Indeed, asked during her deposition what
safety policies she had written, Burrell was unable to name a
single one. Burrell Dep. at 59 (“Q: What policy did you
write? A: I—I don’t recall.”). She was also unable to cite
specific safety-related policies or executive orders or to
articulate “major conflicts in safety policy and program
objectives,” Burrell Dep. at 59–61, 68–70, knowledge
specifically required for the Safety Manager position, Position
Description at 2. In contrast to this relatively weak evidence
of Burrell’s policy knowledge and experience, the evidence
supporting Hamilton’s qualifications demonstrates a deep
                               18
understanding of safety policies and procedures and contains
specific and extensive descriptions of safety policies he
himself developed and administered. See supra 15–16.

     The government argues that Burrell’s perfect KSA score
is dispositive of her comparative qualifications. We disagree.
Not only did Hamilton also have a perfect KSA score, but that
score, a preliminary assessment designed to identify
candidates worthy of further consideration, makes no
comparison of one candidate’s qualifications to another’s. See
Carroll Dep. at 87 (“I don’t rank [the candidates] against each
other. I rank them against the KSAs.”). Underscoring the
preliminary nature of the KSA rankings, the interview
panelists reviewed the candidates’ full application packages,
see Burns Decl. at 2, and considered themselves responsible
for assessing the candidates’ qualifications, see Mitchell Decl.
at 2 (stating that the interview panel assessed candidates “on
their knowledge of the safety program, their knowledge of the
IRS . . . their experience working program items at a national
level and their abilities to lead”). Given all this, a jury could
conclude that the KSA scores were never intended to be
conclusive and that there might be substantial variation in
qualifications between candidates with identical scores,
particularly where, as here, the ranking official had no formal
safety or security training. See Carroll Dep. at 36.

     Accordingly, and drawing all reasonable inferences in
Hamilton’s favor, we believe that a reasonable jury could find
that, by comparison to Burrell, Hamilton had much greater
technical expertise, more experience developing complex,
large-scale safety programs, and far more formal training in
occupational health and safety. This combination of superior
knowledge and experience, in turn, could lead the jury to
conclude that Hamilton was significantly better qualified for
the Safety Manager promotion. But even if this disparity
                              19
alone is insufficient, a reasonable jury, considering
Hamilton’s stronger qualifications together with “other flaws
in the employer’s explanation,” Holcomb, 433 F.3d at 897,
could still reach a verdict in Hamilton’s favor. These flaws
fall into two categories.

     First, the record contains no contemporaneous
documentation of the Secretary’s proffered explanation—that
Burrell outperformed Hamilton in the interview. Neither
selecting official Burns nor the other panelists appear to have
created any written evidence of their deliberations or their
reasons for choosing Burrell, leaving us with no record of the
decisionmaking process beyond notes taken during the
interviews. Burns’s and Mitchell’s notes contain no
comments, positive or negative, regarding Hamilton’s
interview performance or communications skills, thus
weakening their claim that they selected Burrell because
Hamilton’s interview “did not go well,” Mitchell Decl. at 2.
See Aka, 156 F.3d at 1298 (reasoning that the decisionmaker
“did not comment at all on Aka’s enthusiasm (or the lack
thereof) on the interview summary sheet, weakening her
claim that Aka’s lack of enthusiasm motivated her decision”).
Indeed, the only contemporaneous documentation of
Hamilton’s performance appears in Huston’s notes, where he
wrote that Hamilton “[r]estated questions; thinks through
answers,” an observation that a jury could conclude reflected
a judgment that Hamilton carefully and thoughtfully
responded to panelists’ questions. At the very least, Huston’s
comment is ambiguous. And as Hamilton points out, we have
no way of knowing what else Huston may have written during
the interview given that one page (amounting to half of his
notes on Hamilton’s interview) is missing and unaccounted
for. Although we certainly do not suggest that a jury must or
should draw an adverse inference, this absence of
documentation, coupled with the missing page of Huston’s
                              20
interview notes, could lead a reasonable jury to doubt the
Secretary’s explanation, particularly given that the IRS
requires documentation of a promotion action “sufficient for a
reviewer to reconstruct the action in its entirety” as well as
maintenance of complete promotion files for two years.
Internal Revenue Manual § 6.335.1.12.16 (2002).

    Second, the Secretary’s proffered non-discriminatory
explanation relies heavily—indeed entirely—on subjective
considerations, and our case law instructs us to treat such
explanations with caution on summary judgment. See Aka,
156 F.3d at 1298 (noting that “courts traditionally treat
explanations that rely heavily on subjective considerations
with caution” and that “an employer’s heavy use of highly
subjective criteria, such as interpersonal skills, could support
an inference of discrimination” (internal quotation marks
omitted)). Although “employers may of course take subjective
considerations into account in their employment decisions,”
we have repeatedly expressed concern about the ease with
which heavy reliance on subjective criteria may be used to
“mask” or “camouflage” discrimination. Id. (internal
quotation marks omitted). “Subjective criteria,” we have
explained, “lend themselves to racially discriminatory abuse
more readily than do objective criteria.” Harris v. Group
Health Ass’n, Inc., 662 F.2d 869, 873 (D.C. Cir. 1981).

     In our view, several considerations make caution
particularly appropriate here. For one thing, the IRS job
description does not emphasize communications skills,
providing only a brief description of the Security Manager’s
representative and liaison functions at the end of a much more
detailed discussion of the position’s technical knowledge and
policy experience requirements. See Position Description at
2–3. Even assuming that communications skills were critical
to the position, the record contains only vague descriptions of
                              21
Hamilton’s interview performance. Although Burns and
Mitchell stated generally that Hamilton’s answers were
confusing and difficult to follow, they provided no concrete
examples of poor answers that might have grounded their
subjective assessment in more objective facts. Indeed, Burns
appears to have based his assessment of Burrell’s interview
performance in part on her “presentation of self,” Burns Decl.
at 3, a highly subjective criterion that a jury could well view
as “lend[ing]” itself quite “readily” to gender-based or
“racially discriminatory abuse,” Harris, 662 F.2d at 873.
Huston, moreover, could recall nothing at all about
Hamilton’s performance. See Huston Decl. at 2 (stating that
he could not “remember any specifics from the interview”).

     Given the vague and subjective nature of the panelists’
assessment, a jury might find further reason for caution in
Hamilton’s performance evaluation (included in his
application package), which rated him highly in the categories
of “Interaction” and “Verbal Communications/Listening,”
Hamilton Appl. And as mentioned above, Burrell had
substantial difficulty responding to deposition questions about
safety policies she had written or used as a federal safety
professional. See Burrell Dep. at 58–60. Were Burrell to
testify at trial as she did in her deposition, a jury might not
only find her markedly less qualified than Hamilton, but also
doubt the strength of her communications skills and her
ability to perform well under the pressure of an interview.

     To sum up, then, we believe that, when taken together,
the evidence of a significant disparity in the candidates’
qualifications, the highly subjective nature of the Secretary’s
proffered nondiscriminatory explanation, and the absence of
any contemporaneous documentation supporting that
explanation could lead a reasonable jury to disbelieve the
Secretary and to reach a verdict in Hamilton’s favor. Of
                              22
course, after hearing live testimony, assessing witness
credibility, and weighing the evidence, the jury might also
conclude that Hamilton was not significantly more qualified
than Burrell and that Burrell’s interview performance
legitimately tipped a difficult choice in her favor. But the
record suggests that these issues “properly can be resolved
only by a finder of fact because they may reasonably be
resolved in favor of either party.” Anderson v. Liberty Lobby,
Inc., 477 U.S. 242, 250 (1986). We shall therefore reverse the
grant of summary judgment on Hamilton’s discriminatory
promotion claim and remand for trial.

                              IV.
     For his third and final claim, Hamilton contends that the
decision to award Camille Carraway a GS-14 Safety Manager
detail in January 2004 was retaliation for Hamilton’s pursuit
of a discrimination complaint with the IRS EEO office. To
make out a prima facie case of retaliation, a plaintiff must
show that “(1) he engaged in protected activity; (2) he was
subjected to an adverse employment action; and (3) there was
a causal link between the protected activity and the adverse
action.” Woodruff v. Peters, 482 F.3d 521, 529 (D.C. Cir.
2007). Hamilton argues that the close temporal proximity
between the filing of his EEO complaint and Carraway’s
selection is sufficient to establish a prima facie case of
retaliation. We agree.

     For purposes of establishing a prima facie case of
retaliation, “[t]emporal proximity can indeed support an
inference of causation, but only where the two events are very
close in time.” Id. (citation and internal quotation marks
omitted); see also Singletary v. District of Columbia, 351 F.3d
519, 525 (D.C. Cir. 2003) (“[T]his circuit has held that a close
temporal relationship may alone establish the required causal
connection.”). Although the Supreme Court has cited circuit
                              23
decisions suggesting that in some instances a three-month
period between the protected activity and the adverse
employment action may, standing alone, be too lengthy to
raise an inference of causation, neither the Supreme Court nor
this court has established a bright-line three-month rule. See
Clark Cnty. Sch. Dist. v. Breeden, 532 U.S. 268, 273–74
(2001) (citing approvingly cases finding three- and four-
month intervals insufficient to establish a prima facie case,
but holding only that “[a]ction taken . . . 20 months later
suggests, by itself, no causality at all”). Instead, we have
evaluated the specific facts of each case to determine whether
inferring causation is appropriate. Cf. Taylor v. Solis, 571
F.3d 1313, 1322 (D.C. Cir. 2009) (finding a two-and-a-half
month interval insufficient to overcome the employer’s
asserted non-retaliatory explanation “on the record [in that
case],” without addressing the temporal proximity required to
establish a prima facie case).

     When the district court evaluated Hamilton’s temporal
proximity claim, it considered only the interval between
Hamilton’s August 2003 EEO counseling session and the
January 20, 2004 decision to detail Carraway—a five-month
interval the court found insufficient to establish causation.
Hamilton I, 542 F. Supp. 2d at 57–58. Apparently believing
that only Hamilton’s first statutorily protected activity was
relevant to the temporal proximity analysis, the district court
rejected his argument that proximity should instead be
measured from October 21, 2003, when he filed his formal
EEO complaint. Id. at 58. As Hamilton points out, however,
we have held that courts should consider later protected
activity in determining whether evidence of temporal
proximity satisfies the causation element. See, e.g., Jones, 557
F.3d at 680 (“[B]ecause Title VII and the ADEA protect
employees who engage in any protected activity, we have
repeatedly held that an adverse action following closely on
                              24
the heels of protected activity may in appropriate cases
support an inference of retaliation even when occurring years
after the initial filing of charges.”); Singletary, 351 F.3d at
524 (finding error where “[i]n concluding that there was
insufficient temporal proximity between the defendants’
alleged retaliatory actions and Singletary’s protected activity,
the district court failed to take account of protected activity
that Singletary undertook long after the original protected
activity” (internal quotation marks omitted)).

     Measured from the October filing of Hamilton’s formal
complaint, the period between his statutorily protected
activity and the adverse employment action is just under three
months. Moreover, given Hamilton’s claim that Burns
“ignored” him in December 2003 when he requested
information regarding the detail, Appellant’s Br. 40; see also
Hamilton Aff. at 8, it appears that Burns actually took a first
step toward the adverse action just two months after Hamilton
filed his formal complaint. The Secretary insists that
Hamilton never argued in the district court that Burns’s
December 2003 brush-off constituted an adverse employment
action. But Hamilton did allege that Burns’s behavior formed
part of a pattern of antagonism leading up to the adverse
action, see Hamilton I, 542 F. Supp. 2d at 60, and we consider
it here as additional evidence supporting an inference of
causation. The record before us, then, suggests that Hamilton
was denied information about a possible detail just two
months after filing an EEO complaint and, approximately one
month later, was ultimately passed over for the detail. The
Secretary claims that Hamilton failed to show that Burns
knew of his complaint, but at the prima facie stage the fact
that Hamilton submitted the complaint to the agency is
sufficient. See Jones, 557 F.3d at 679 (suggesting that the
agency’s knowledge of protected activity may be sufficient, at
least at the prima facie stage).
                              25
     Considering the “minimal burden” imposed at the prima
facie stage, Holcomb, 433 F.3d at 903, we find the evidence
sufficient to establish a prima facie case of retaliation. The
Secretary, pointing out that he has already come forth with a
legitimate, non-retaliatory explanation for Carraway’s
selection, Def.’s Mot. for Summ. J. at 17–18, urges us to
resolve “the ultimate issue of retaliation vel non,” Jones, 557
F.3d at 678. But given that the issue is not fully briefed on
appeal, we decline to do so. See Liberty Property Trust v.
Republic Properties Corp., 577 F.3d 335, 341 (D.C. Cir.
2009) (“Although we review all questions of law de novo and
have the discretion to consider questions of law that were not
passed upon by the District Court, this court’s normal rule is
to avoid such consideration.” (alterations and internal
quotation marks omitted)). Instead, we shall remand
Hamilton’s retaliation claim for the district court to determine
in the first instance whether a reasonable jury could conclude
that the Secretary’s proffered explanation was pretext for
retaliation, keeping in mind that “positive evidence beyond
mere proximity is required to defeat the presumption that the
proffered explanations are genuine.” Woodruff, 482 F.3d at
530.

                              V.
     For the foregoing reasons, we affirm the district court’s
grant of summary judgment on Hamilton’s 2002 detail claim.
We reverse the grant of summary judgment on Hamilton’s
promotion discrimination and retaliation claims and remand
for further proceedings consistent with this opinion.

                                                    So ordered.
