  United States Court of Appeals
      for the Federal Circuit
                ______________________

                SUSAN FITZGERALD,
                     Petitioner

                           v.

    DEPARTMENT OF HOMELAND SECURITY,
                 Respondent
           ______________________

                      2015-3154
                ______________________

   Petition for review of the Merit Systems Protection
Board in No. AT-0831-14-0684-I-1.
                ______________________

              Decided: September 20, 2016
                ______________________

    JOHN C. HERMAN, Robbins Geller Rudman & Dowd
LLP, Atlanta, GA, argued for petitioner. Also represented
by CARLTON JONES, ROBERT JAMES LEONARD.

    TARA K. HOGAN, Commercial Litigation Branch, Civil
Division, United States Department of Justice, Washing-
ton, DC, argued for respondent. Also represented by
BENJAMIN C. MIZER, ROBERT E. KIRSCHMAN, JR., PATRICIA
M. MCCARTHY, KRISTIN MCGRORY.
                 ______________________

     Before DYK, SCHALL, and HUGHES, Circuit Judges.
2                                         FITZGERALD   v. DHS



SCHALL, Circuit Judge.
    Susan Fitzgerald is an employee of U.S. Customs and
Border Protection (“the Agency”), a component of the
Department of Homeland Security (“DHS”). She current-
ly works as a “Law Enforcement Specialist (Foren-
sics/Investigative Instructor)” at the Federal Law
Enforcement Training Center (“FLETC”) in Glynco,
Georgia. In this appeal, she challenges the April 2, 2015
final decision of the Merit Systems Protection Board
(“Board”) that sustained the denial by the Agency of her
request for secondary Customs and Border Protection
Officer (“CBPO”) retirement credit based upon her service
as an Instructor at FLETC. J.A. 1–8. For the reasons set
forth below, we affirm.
                       BACKGROUND
                             I.
    Federal retirement laws extend enhanced benefits to
certain groups, such as law-enforcement officers (“LEOs”)
and firefighters, who have served in physically rigorous
positions. Under the Federal Employees’ Retirement
System (“FERS”), 1 those benefits include, inter alia,
eligibility to retire with an annuity at an earlier age than
many other federal employees and eligibility to retire
based on fewer years of service. Compare 5 U.S.C.
§ 8412(a) (2012) (providing an annuity once an employee


    1   Congress established FERS in 1986 as a successor
to the retirement benefits scheme for federal employees
under the Civil Service Retirement System. See Federal
Employees’ Retirement System Act of 1986, Pub. L.
No. 99–335, § 101, 100 Stat. 514, 516–17; S. REP. NO. 99-
166, at 1 (1986). Both systems presently remain in effect;
persons employed on or after January 1, 1984, are auto-
matically placed in FERS. See 5 U.S.C. § 8401(11) (1988);
42 U.S.C. § 410(a)(5) (1988).
FITZGERALD   v. DHS                                      3



has reached the age of 55 and has completed 30 years of
service) with id. § 8412(d)(1),(2) (providing an annuity at
any age after completing 25 years of service as an LEO or
firefighter, or after reaching the age of 50 and completing
20 years of such service). Germane to this case, in 2007,
Congress passed legislation (“the Act”) that amended the
federal retirement statutes to provide to employees who
qualify as CBPOs enhanced retirement benefits similar to
those available to LEOs and firefighters. See Consolidat-
ed Appropriations Act, 2008, Pub. L. No. 110–161, § 535,
121 Stat. 1844, 2075–77. The Act became effective on
July 6, 2008. See id. § 535(e)(1). As charged by section
535(d) of the Act, the Office of Personnel Management
(“OPM”) has issued regulations governing enhanced
retirement benefits for CBPOs. See Customs and Border
Protection Officer Retirement, 76 Fed. Reg. 41,993 (July
18, 2011) (codified at 5 C.F.R. pt. 842, subpt. J).
                            II.
    Ms. Fitzgerald began her career with the federal gov-
ernment as an Immigration Inspector (GS-1816 series)
with the Immigration and Naturalization Service (“INS”)
of the Department of Justice. She worked in that capacity
from August 2, 1987, to July 2, 1988. Subsequently, from
July 3, 1988, to May 6, 2000, she served as a Customs
Inspector (GS-1890 series) with the Customs Service
(“Customs”) of the Department of the Treasury. 2


   2    In March 2003, INS ceased to exist and its func-
tions were transferred to DHS. At the same time, Cus-
toms became part of DHS and the agency was renamed
the Bureau of Customs and Border Protection. See Home-
land Security Act of 2002, Pub. L. No. 107–296, § 1502,
116    Stat.   2135,   2308;   REORGANIZATION      PLAN
MODIFICATION FOR THE DEPARTMENT OF HOMELAND
SECURITY, H.R. DOC. NO. 108–32, at 4 (2003). Subse-
quently, the agency was renamed U.S. Customs and
4                                        FITZGERALD   v. DHS



Ms. Fitzgerald has been continuously employed in various
Instructor positions at FLETC since May of 2000. 3 One of
her main responsibilities while at FLETC has been
providing training to criminal investigators and LEOs
from various federal organizations.
    On August 3, 2012, Ms. Fitzgerald requested that the
Agency review her employment history so that she could
obtain CBPO retirement credit for her past service with
INS and Customs. The Agency denied her request on
July 25, 2013, stating that the Act did not provide “retro-
active service” credit for service performed before July 6,
2008, the effective date of the Act. Ms. Fitzgerald re-
quested reconsideration and sought CBPO credit for her
service at FLETC after the Act’s effective date; the Agen-
cy denied her request on April 17, 2014.
                           III.
     Ms. Fitzgerald timely appealed the denial of her claim
to the Board. After conducting a hearing on September
19, 2014, the administrative judge (“AJ”) to whom the
appeal was assigned affirmed the Agency’s denial in an
initial decision dated September 29, 2014. Fitzgerald v.
Dep’t of Homeland Sec., AT-0831-14-0684-I-1, 2014 WL
4987282 (Sept. 29, 2014) (“Initial Decision”). In arriving
at his decision, the AJ examined the pertinent statutory
and regulatory framework for determining whether



Border Protection. See Name Change From the Bureau of
Immigration and Customs Enforcement to U.S. Immigra-
tion and Customs Enforcement, and the Bureau of Cus-
toms and Border Protection to U.S. Customs and Border
Protection, 72 Fed. Reg. 20,131 (Apr. 23, 2007).
    3   The record indicates that Ms. Fitzgerald has been
an Instructor at FLETC since May of 2000, even though
her position title has changed. See J.A. 205, 207, 215,
221.
FITZGERALD   v. DHS                                       5



Ms. Fitzgerald is entitled to CBPO retirement credit
based upon her service at FLETC.
    The Act amended FERS to make CBPOs eligible for
enhanced retirement benefits. See Consolidated Appro-
priations Act, 2008, § 535(b)(2) (codified at 5 U.S.C.
§ 8412(d)). The Act defines a CBPO as
   an employee in [DHS] (A) who holds a position
   within the GS-1895 job series (determined apply-
   ing the criteria in effect as of September 1, 2007)
   or any successor position, and (B) whose duties in-
   clude activities relating to the arrival and depar-
   ture of persons, conveyances, and merchandise at
   ports of entry, including any such employee who is
   transferred directly to a supervisory or adminis-
   trative position in [DHS] after performing such
   duties (as described in subparagraph (B)) in 1 or
   more positions (as described in subparagraph (A))
   for at least 3 years.
Id. § 535(b)(1)(C) (codified at 5 U.S.C. § 8401(36)) (empha-
sis added). As noted, the amendments made by section
535 of the Act became effective on July 6, 2008. See id.
§ 535(e)(1). In regard to service performed before its
effective date, the Act provides as follows:
   (i) GENERAL RULE.—Except as provided in
   clause (ii), nothing in this section or any amend-
   ment made by this section shall be considered to
   apply with respect to any service performed as a
   [CBPO] before [July 6, 2008].
   (ii) EXCEPTION.—Service described in section . .
   . 8401(36) . . . rendered before [July 6, 2008] may
   be taken into account to determine if an individu-
   al who is serving on or after such effective date
   then qualifies as a [CBPO] by virtue of holding a
   supervisory or administrative position in [DHS].
6                                         FITZGERALD   v. DHS



Id. § 535(e)(2)(B)(i)-(ii) (emphasis added). Thus, while not
retroactive, the Act is retrospective. In other words, it
does not allow service rendered before the July 6, 2008
effective date to form the basis for CBPO retirement
credit. However, it does permit such prior service to be
considered when determining whether a position held in
DHS on or after the effective date (Ms. Fitzgerald’s cir-
cumstance) qualifies as a “supervisory or administrative”
position for purposes of CBPO retirement credit (the
question in Ms. Fitzgerald’s case). See 76 Fed. Reg. at
41,994 (explaining that if an individual is in a supervisory
or administrative position on July 6, 2008, that individu-
al’s eligibility to be a CBPO will be determined by “look-
ing back at the individual’s employment history to
determine whether the requirements for coverage would
have been met if the provisions of [section] 535 had been
in effect during the earlier employment history”).
    Pursuant to its authority to promulgate regulations to
implement the amendments to FERS, OPM issued final
regulations governing enhanced retirement benefits for
CBPOs on July 18, 2011. The regulations’ definition of
CBPO relates to the definition of CBPO in 5 U.S.C.
§ 8401(36). See 5 C.F.R. § 842.1002. Like the statute, the
regulations split CBPOs into two categories of positions
(referred to in the regulations as “primary” and “second-
ary” positions) for which early retirement coverage under
5 U.S.C. § 8412(d) may be available. See id.
    Under the regulations, a primary CBPO position is a
position “classified within the [CBPO] (GS–1895) job
series (determined applying the criteria in effect as of
September 1, 2007) or any successor position whose duties
include the performance of work directly connected with
activities relating to the arrival and departure of persons,
conveyances, and merchandise at ports of entry.” 5 C.F.R.
§ 842.1002. As will be seen, Ms. Fitzgerald does not
contend that her employment at FLETC has been in
primary CBPO positions. Rather, she argues that her
FITZGERALD   v. DHS                                       7



employment at FLETC has been in secondary CBPO
positions and that, for that reason, she is entitled to
CBPO retirement credit. Pertinent to Ms. Fitzgerald’s
claim, a secondary CBPO position is a position in DHS
that is either:
   (1) Supervisory; i.e., a position whose primary du-
   ties are as a first-level supervisor of [CBPOs] in
   primary positions; or
   (2) Administrative; i.e., an executive, managerial,
   technical, semiprofessional, or professional posi-
   tion for which experience in a primary [CBPO] po-
   sition is a prerequisite.
Id. (emphasis added).
     An employee’s service in a primary CBPO position is
automatically “covered,” meaning the service is credited
toward retirement eligibility under 5 U.S.C. § 8412(d).
See id. § 842.1003(a)(1). However, in order for an employ-
ee’s service in a secondary CBPO position to be covered,
the regulations require that the service meet certain
criteria. See id. § 842.1003(b). With some exceptions not
applicable to this case, the employee must have
(1) transferred directly (i.e., without a break in service
exceeding 3 days) from a primary position to a secondary
position, (2) completed 3 years of service in a primary
position, and (3) been continuously employed in secondary
positions since transferring from a primary position
without a break in service exceeding 3 days. See id.
§ 842.1003(b)(1)-(3).    Because the determination of
whether an employee is in a covered secondary position
might, as it does here in Ms. Fitzgerald’s case, require
consideration of employment periods that occurred before
September 1, 2007, the regulations include counterpart
definitions of primary and secondary positions solely for
the purpose of applying the criteria of § 842.1003(b)(1)-(3)
to those periods. See id. § 842.1003(c). A primary posi-
tion in that context (hereinafter, a “Retrospective CBPO
8                                         FITZGERALD   v. DHS



Position”) is deemed to include a CBPO position classified
in the GS-1895 series and a predecessor CBPO position
that would have been classified in the GS-1895 series had
it then existed. 4 See id. § 842.1003(c)(1)(i)-(ii). For the
same purpose, the regulations provide that a secondary
position in that context includes:
    (i) A first-level supervisor of an employee in [a
    Retrospective CBPO Position]; or
    (ii) A executive, managerial, technical, semipro-
    fessional, or professional position for which expe-
    rience in [a Retrospective CBPO Position] is a
    mandatory prerequisite.




    4  Specifically, § 842.1003(c)(1)(i)-(ii) provides that a
Retrospective CBPO Position includes:
    (i) A position whose duties included the perfor-
    mance of work directly connected with activities
    relating to the arrival and departure of persons,
    conveyances, and merchandise at ports of entry
    that was classified within the Immigration In-
    spector Series (GS–1816), Customs Inspector Se-
    ries (GS–1890), Canine Enforcement Officer
    Series (GS–1801), or any other series which the
    agency head determines were predecessor series
    to the Customs and Border Protection Series (GS–
    1895), and that would have been classified under
    the GS–1895 series had it then existed; and
    (ii) A position within the Customs and Border Pro-
    tection Series (GS–1895) whose duties included
    the performance of work directly connected with
    activities relating to the arrival and departure of
    persons, conveyances, and merchandise at ports of
    entry.
FITZGERALD   v. DHS                                         9



Id. § 842.1003(c)(2)(i)-(ii) (emphasis added).
    Before the Board, Ms. Fitzgerald did not contend that
any of her Instructor positions at FLETC were primary
positions; instead, she argued that they were secondary
positions. Thus, to be entitled to CBPO retirement credit
for her service at FLETC from the effective date of the Act
(July 6, 2008) forward, Ms. Fitzgerald’s prior service had
to meet the criteria of § 842.1003(b)(1)-(3) and her In-
structor positions after July 6, 2008, had to be secondary
positions under § 842.1002.
    In considering Ms. Fitzgerald’s prior service, the AJ
began by looking to the rules for service that occurred
before September 1, 2007, because Ms. Fitzgerald trans-
ferred to FLETC in the year 2000. The AJ found that
Ms. Fitzgerald’s positions at INS and Customs qualified
as Retrospective CBPO Positions, which meant she had
completed the requisite 3 years of service in a primary
position before transferring to FLETC. See Initial Deci-
sion at 4. Next, the AJ considered whether the Instructor
position at FLETC to which Ms. Fitzgerald initially
transferred (“the Initial Position”) qualified as a second-
ary position. The AJ found that “there is no evidence”
that the Initial Position qualified as a “first-level supervi-
sor” position under § 842.1003(c)(2)(i). See id. Thus, the
AJ explained, in order to meet the requirements of
§ 842.1003(b)(1), the Initial Position had to be an execu-
tive, managerial, technical, semiprofessional, or profes-
sional position for which experience in a Retrospective
CBPO Position was a mandatory prerequisite, as required
by § 842.1003(c)(2)(ii). See id.
    On this point, the AJ looked to the Initial Position’s
job description and determined that experience in a
Retrospective CBPO Position was not a prerequisite for
10                                        FITZGERALD   v. DHS



the position. 5 Rather, the AJ noted, the position descrip-
tion only required experience or knowledge as an LEO.
Id. According to the AJ, although Ms. Fitzgerald acquired
the requisite knowledge and skill to qualify for the Initial
Position through her years of service in Retrospective
CBPO Positions with INS and Customs, the position
description included no language suggesting that
knowledge or experience unique to CBPOs was required
to perform the duties of the Initial Position. See id. at 4–
5. The AJ therefore concluded that the Initial Position
did not qualify as a secondary position under
§ 842.1003(c)(2)(ii). Id. at 5. Consequently, the AJ found
that Ms. Fitzgerald could not establish that, when she
stepped into the Initial Position, she transferred directly
from a primary position to a secondary position. Id. She
therefore could not establish that her prior service met all
of the criteria of § 842.1003(b)(1)-(3). 6 See id.



     5  The AJ noted that Ms. Fitzgerald and the Agency
disputed the position description under which the Initial
Position fell. Initial Decision at 4. However, for the
purpose of this case, the AJ assumed that Ms. Fitzgerald’s
proffered description was correct. See id. We do too.
    6   In light of his determination that Ms. Fitzgerald
did not transfer directly from a primary to a secondary
position, the AJ added that, even if the Instructor posi-
tions to which Ms. Fitzgerald was later assigned qualified
as secondary positions, her time at FLETC could not be
credited toward retirement because she was employed in
the Initial Position for more than 3 days. See id. at 5.
Thus, contrary to the requirements of 5 C.F.R.
§ 842.1003(b), Ms. Fitzgerald had a break in service
exceeding 3 days between a primary position (the last of
her Retrospective CBPO Positions) and the first Instruc-
tor position she held after the Initial Position. The AJ
accordingly did not determine whether her Instructor
FITZGERALD   v. DHS                                       11



    In addition to her arguments on the merits of her eli-
gibility for CBPO retirement credit, Ms. Fitzgerald as-
serted that OPM’s regulations were inconsistent with the
statute. The AJ disagreed. In his view, OPM’s interpre-
tation of the phrase “supervisory or administrative posi-
tion in [DHS]” in 5 U.S.C. § 8401(36) is entitled to
deference because, “at best, the statute is ambiguous”
regarding its meaning. See id. at 8 n.2. Accordingly, the
AJ affirmed the Agency’s denial of Ms. Fitzgerald’s claim
for CBPO retirement credit for her service at FLETC from
July 6, 2008, onward. Id. at 5.
    Ms. Fitzgerald filed a petition for review of the Initial
Decision. Echoing the AJ’s reasoning, a two-member
panel of the Board denied the petition and affirmed the
Initial Decision, which became the Board’s final decision.
See J.A. 1–9. Ms. Fitzgerald timely petitioned for review
of the final decision. We have jurisdiction pursuant to
28 U.S.C. § 1295(a)(9).
                        DISCUSSION
                             I.
     We review the Board’s decision to determine whether
it is “(1) arbitrary, capricious, an abuse of discretion, or
otherwise not in accordance with law; (2) obtained with-
out procedures required by law, rule, or regulation having
been followed; or (3) unsupported by substantial evi-
dence.” 5 U.S.C. § 7703(c) (2012); Miller v. Fed. Deposit
Ins. Corp., 818 F.3d 1361, 1365 (Fed. Cir. 2016). “Under
the substantial evidence standard, this court reverses the
Board’s decision only ‘if it is not supported by such rele-
vant evidence as a reasonable mind might accept as
adequate to support a conclusion.’” Shapiro v. Soc. Sec.
Admin., 800 F.3d 1332, 1336 (Fed. Cir. 2015) (quoting


positions from July 6, 2008, forward in fact qualified as
secondary positions under § 842.1002.
12                                         FITZGERALD   v. DHS



Abrams v. Soc. Sec. Admin., 703 F.3d 538, 542 (Fed. Cir.
2012)).
     Ms. Fitzgerald makes two arguments on appeal.
First, she contends that the regulations upon which the
Board based its decision should be found invalid for
contradicting the plain language of 5 U.S.C. § 8401(36).
And second, she urges that, even if the regulations are not
invalid, the Board’s decision should be reversed because
the Initial Position was a secondary position. We turn
first to her challenge to the regulations.
                             II.
                             A.
    “Our review of questions of statutory interpretation is
de novo, except to the extent deference to an agency’s
construction of a statute it administers is required under
the two-step analysis set forth in Chevron.” NSK Ltd. v.
United States, 390 F.3d 1352, 1354 (Fed. Cir. 2004) (cita-
tion omitted); see also Vassallo v. Dep’t of Def., 797 F.3d
1327, 1330 (Fed. Cir. 2015) (explaining that we review an
agency’s statutory interpretation using the two-pronged
framework established by Chevron). The first prong of
Chevron requires us to assess “whether Congress has
directly spoken to the precise question at issue”; if so, we
“must give effect to the unambiguously expressed intent
of Congress.” Chevron, U.S.A., Inc. v. Nat. Res. Def.
Council, Inc., 467 U.S. 837, 842–43 (1984). If the statute
does not answer the specific question at issue, however,
meaning that it is “silent or ambiguous,” then, under
prong two of Chevron, we must determine whether the
agency provided “a permissible construction of the stat-
ute.” Id. at 843; Hymas v. United States, 810 F.3d 1312,
1318 (Fed. Cir. 2016). “If Congress has explicitly left a
gap for [an] agency to fill, there is an express delegation of
authority to the agency to elucidate a specific provision of
the statute by regulation.” Chevron, 467 U.S. at 843–44.
“Such legislative regulations are given controlling weight
FITZGERALD   v. DHS                                       13



unless they are arbitrary, capricious, or manifestly con-
trary to the statute.” Id. at 844. In other words, to sur-
vive judicial scrutiny, an agency’s interpretation of an
ambiguous statute need not be “the only reasonable
interpretation or even the most reasonable interpreta-
tion.” Yangzhou Bestpak Gifts & Crafts Co. v. United
States, 716 F.3d 1370, 1377 (Fed. Cir. 2013) (citation
omitted).
    Ms. Fitzgerald argues that OPM’s regulations—
namely, 5 C.F.R. §§ 842.1002 (defining secondary posi-
tion) and 842.1003(c)(2) (defining secondary position
retrospectively, prior to the effective date of the Act)—
impermissibly contradict the plain language and purpose
of 5 U.S.C. § 8401(36). In her view, § 8401(36) expressly
provides that employees are entitled to CBPO status in a
secondary position if they served in a covered primary
position for at least 3 years (as she had prior to her trans-
fer to FLETC) and then transferred directly to a supervi-
sory or administrative position in DHS (as she contends
she did). Because the statute does not qualify the latter
requirement, she reasons, it entitles CBPOs who trans-
ferred to any supervisory or administrative position to
maintain CBPO status so long as that position is “in
DHS.” Ms. Fitzgerald further argues that OPM’s regula-
tions contradict the broad language of the statute by
further restricting entitlement to CBPO status to only
those CBPOs who transfer or transferred into (a) CBPO-
specific supervisory positions or (b) administrative posi-
tions that require CBPO-related experience as a prerequi-
site.
    In support of her position, Ms. Fitzgerald avers that
OPM’s regulations also conflict with the purpose of the
statute. According to Ms. Fitzgerald, the legislative
history shows that the Act was intended to help recruit
and retain CBPOs by providing to them the same retire-
ment benefits enjoyed by LEOs. The regulations do not
promote these goals, she contends, because, under the
14                                        FITZGERALD   v. DHS



regulations, CBPOs may not transfer to positions for
which their experience is valuable but not a prerequisite
without losing their CBPO status and associated retire-
ment credit. Without such flexibility, Ms. Fitzgerald
reasons, CBPOs have less incentive to work at DHS.
    For its part, the government contends that the statute
is silent regarding what constitutes a “supervisory or
administrative” position for purposes of CBPO status.
Given this silence, and pursuant to its statutory authority
to administer the Act, the government argues, OPM
promulgated valid regulations that are entitled to defer-
ence under Chevron. In the government’s view, Con-
gress’s reliance on OPM to fill the gaps as to the meaning
of the term “supervisory or administrative” position is
consistent with its approach to retirement benefits for
other special groups (e.g., LEOs and firefighters), which
indicates it intended for the Act to be implemented in the
same manner. The government also suggests that Con-
gress’s silence as to the meaning of this term is consistent
with its express delegation of rulemaking authority to
OPM to administer the Act.
    Regarding prong two of Chevron, the government urg-
es that OPM’s interpretation is based on a permissible
construction of the statute. According to the government,
the regulations are consistent with the purpose of recruit-
ing and retaining CBPOs because they provide enhanced
retirement benefits to CBPOs consistent with those
enjoyed by other special groups, and they ensure that
senior CBPOs stay in the Agency to share their
knowledge and experience with junior CBPOs.
                            B.
    In our view, Congress has not directly spoken to the
precise question at issue in this case. We have explained
that “[i]dentifying ‘the precise question at issue’ is a
necessary prerequisite to determining whether or not
Congress has directly spoken on it.” GHS Health Maint.
FITZGERALD   v. DHS                                        15



Org., Inc. v. United States, 536 F.3d 1293, 1297 (Fed. Cir.
2008) (quoting Chevron, 467 U.S. at 842). The precise
question at issue here, we think, is this: what constitutes
a supervisory or administrative position in DHS for the
purpose of meeting the definition of a CBPO? The statute
is silent on this question. See 5 U.S.C. § 8401. Section
8401(36) defines a CBPO to include an “employee who is
transferred directly to a supervisory or administrative
position in [DHS].” Id. (emphasis added). The terms
“supervisory” and “administrative” are not defined within
the definition of a CBPO, however. Nor are they defined
in any other part of the statute. In fact, the definitions for
an LEO and a firefighter also include the “employee who
is transferred directly to a supervisory or administrative
position” language, but those definitions likewise fail to
explain what constitutes a “supervisory or administrative
position.” See id. § 8401(14),(17),(33). Consequently, we
think the statute does not clearly and unequivocally
answer the question at hand.
    Congress’s awareness of OPM’s approach to other spe-
cial retirement groups bolsters our conclusion on the first
prong of Chevron. As noted, LEOs and firefighters al-
ready received enhanced retirement benefits when the Act
was enacted in 2007. Because the statute in place did not
define “supervisory or administrative” positions for the
purpose of qualifying as an LEO or a firefighter, OPM
issued regulations that did. See 5 C.F.R. § 842.802.
Given the general presumption that “Congress is knowl-
edgeable about existing law pertinent to the legislation it
enacts,” Goodyear Atomic Corp. v. Miller, 486 U.S. 174,
184–85 (1988); see also Minneapolis & St. Louis Ry. Co. v.
United States, 361 U.S. 173, 187 (1959) (presuming that
Congress was aware of applicable regulations when
enacting pertinent legislation), we agree with the gov-
ernment that Congress likely intended for the framework
for CBPOs to be implemented similarly to that for LEOs
and firefighters. Put another way, Congress likely in-
16                                      FITZGERALD   v. DHS



tended to leave a gap as to the meaning of a “supervisory
or administrative position in [DHS]” that OPM would fill
through regulations. Finally, our view of Congress’s
approach to § 8401(36) is also consistent with the Act’s
express delegation of rulemaking authority to OPM for
the purpose of carrying out the amendments made by the
Act. Consolidated Appropriations Act, 2008, § 535(d)
(“Any regulations necessary to carry out the amendments
made by [section 535] shall be prescribed by the Director
of [OPM].”); see also 5 U.S.C. § 8461(g) (providing OPM
the authority to “prescribe regulations to carry out the
provisions of [FERS]”).
    Contrary to Ms. Fitzgerald’s assertion, neither the
statute nor the legislative history clearly demonstrates
that Congress intended for secondary CBPO positions to
include any supervisory or administrative position in
DHS. Section 8401(36) plainly refers to “a” supervisory or
administration position, not “any” such position. Accept-
ing Ms. Fitzgerald’s interpretation would impermissibly
read the word “any” into the statute. See Vallee v. Office
of Pers. Mgmt., 58 F.3d 613, 615 (Fed. Cir. 1995) (“It is
incorrect to read a statute contrary to its plain text,
absent compelling evidence of contrary congressional
intent.”) Lest there be any doubt on this point, counsel
for Ms. Fitzgerald agreed at oral argument before us that
§ 8401(36) cannot refer to any supervisory or administra-
tive position in DHS. Oral Arg. at 3:34–40, available at
http://oralarguments.cafc.uscourts.gov/default.aspx?fl=20
15-3154.mp3 (The Court: So you agree that [§ 8401(36)]
cannot be any supervisory or administrative position in
[DHS], right? Counsel: Correct.).
    Accordingly, we conclude that Congress has not “di-
rectly spoken” to the question of what constitutes a su-
pervisory or administrative position in DHS for the
purpose of meeting the definition of a CBPO under
§ 8401(36). We will therefore defer to OPM’s interpreta-
FITZGERALD   v. DHS                                       17



tion as long as it is “a permissible construction of the
statute.” Chevron, 467 U.S. at 843.
                             C.
    Turning to prong two of Chevron, we think 5 C.F.R.
§§ 842.1002 and 842.1003(c)(2) are based on a permissible
construction of the statute. As noted, the regulations do
not conflict with the statute; instead, they merely cabin it
by restricting entitlement to CBPO status to employees in
certain CBPO-related positions. See 5 C.F.R. §§ 842.1002,
842.1003(c)(2). This restriction is reasonable for at least
two reasons. First, it is reasonable to conclude that, for
purposes of attaining CBPO status, all supervisory and
administrative positions in DHS are not created equal.
Indeed, there are likely many supervisory and adminis-
trative positions in DHS that have no connection to the
CBPO occupation. After all, the Agency is only one of
many governmental entities in DHS. See 6 U.S.C. § 203;
REORGANIZATION        PLAN     MODIFICATION     FOR     THE
DEPARTMENT OF HOMELAND SECURITY, H.R. DOC. NO. 108–
32, at 4 (2003). Absent a restriction on where CBPOs in
primary positions may transfer, a CBPO might be able to
transfer, for example, to a position as an administrative
assistant in human resources or to a position as an office
administrator—positions for which CBPO experience is
presumably neither required nor relevant—while main-
taining the benefits of CBPO status for purposes of re-
tirement. We do not think it is unreasonable to conclude
that Congress did not intend for such results to occur. 7


    7    Notably, like the regulations for CBPOs, the regu-
lations for LEOs and firefighters also restrict LEO and
firefighter status to employees who transfer into (a) LEO-
or firefighter-specific supervisory positions or (b) adminis-
trative positions that require law-enforcement or fire-
fighting experience as a prerequisite. See 5 C.F.R.
§ 842.802.
18                                        FITZGERALD   v. DHS



And second, the restriction encourages career service as a
CBPO. OPM explained that “one policy goal of special
retirement coverage is to encourage career service by an
employee in the particular occupation chosen by the
employee.” 76 Fed. Reg. at 41,996. Enticing employees in
primary CBPO positions to transfer into, and remain in,
CBPO-related positions in order to maintain CBPO status
is a sound method for trying to increase the number of
employees who remain in CBPO-related occupations
throughout their careers. 8
    In any event, Ms. Fitzgerald does not explicitly argue
that OPM’s interpretation is an impermissible construc-
tion of the statute. Rather, she asserts that the regula-
tions are inconsistent with the purpose of the Act, which
could be read as a contention that the regulations are
unreasonable.     Either way, we are not persuaded.
Ms. Fitzgerald cites legislative history that suggests the
purpose of the Act is “to help recruit and retain [CBPOs]
by providing them the same retirement benefits as other
[LEOs].” H.R. REP. NO. 110-181, at 9 (2008). But even if
we accept that the cited legislative history accurately
reflects what Congress had in mind when it drafted the
Act, the fact remains that the regulations do not limit the
retirement benefits of CBPOs as compared to those of
LEOs. Instead, they merely restrict who may attain
CBPO status in order to obtain the same retirement



     8   In our view, the regulations at issue are likely to
achieve the stated “policy goal” because employees will be
motivated to maintain CBPO status for at least 25 years
(or for at least 20 years if they have reached the age of 50)
in order to be eligible for early retirement with an annuity
on account of their CBPO status.              See 5 U.S.C.
§ 8412(d)(1),(2). Consequently, employees who start a
career as a CBPO will have an incentive to stay in CBPO-
related positions for the rest of their careers.
FITZGERALD   v. DHS                                     19



benefits as LEOs. In addition, while it may be true that
more flexible regulations (e.g., ones allowing CBPOs to
maintain their CBPO status even after transferring into
secondary positions not having the existing, prior-
experience requirement) would help recruit and retain
CBPOs better than the regulations at issue do, that fact
alone does not render OPM’s interpretation unreasonable.
See Yangzhou, 716 F.3d at 1377 (explaining that an
agency’s interpretation need only represent a “reasonable
construction of the statute,” not necessarily “the most
reasonable interpretation”) (citation omitted).
    Accordingly, because we find that Congress has not
answered the specific question at issue and because we
find that OPM has provided a permissible construction of
the statute, we conclude that the regulations at issue are
not invalid.
                           III.
                            A.
    We now turn to the Agency’s denial of Ms. Fitzgerald’s
claim for retirement credit for her service at FLETC from
July 6, 2008, forward.
    Ms. Fitzgerald asserts that, even if the regulations at
issue are not invalid, the Board incorrectly determined
that the Initial Position was not a secondary position.
The parties do not dispute that the Initial Position was
not    a   supervisory     position    under    5    C.F.R.
§ 842.1003(c)(2)(i). Ms. Fitzgerald also concedes that the
job description for the Initial Position did not explicitly
state that experience in customs and border protection
was required. Nevertheless, in her view, the job descrip-
tion made clear that the Initial Position required CBPO-
related experience because it stated that FLETC Instruc-
tors must have the knowledge to train LEOs from a “wide
variety” of Federal organizations, which she suggests
includes the specialized law-enforcement area of customs
20                                        FITZGERALD   v. DHS



and border protection. According to Ms. Fitzgerald,
FLETC would not have hired her but for her prior experi-
ence in Retrospective CBPO Positions.
    The government responds that there is no evidence in
the record indicating that the Initial Position required
experience in a Retrospective CBPO Position. In its view,
the job description alone is substantial evidence that an
individual could have obtained the Initial Position with-
out ever having served in a Retrospective CBPO Position.
                            B.
    As explained above, in order for Ms. Fitzgerald to pre-
vail on her claim for retirement credit based upon her
serving as an Instructor at FLETC, the Board had to find,
inter alia, that CBPO experience in a Retrospective CBPO
Position was a mandatory prerequisite for the Initial
Position, meaning the Initial Position qualified as a
secondary position under § 842.1003(c)(2)(ii). If such
experience was not a prerequisite, Ms. Fitzgerald’s service
could not meet the criteria of § 842.1003(b). The Board
concluded that the job description for the Initial Position
indicated that such experience was not a prerequisite.
J.A. 6–7. After reviewing the job description, we see no
reason to disturb the Board’s conclusion. See 5 C.F.R.
§ 842.1004(b) (“A determination under § 842.1003(b) must
be based on the official position description and any other
evidence deemed appropriate by the agency head for
making the determination.”).
    On its face, the job description only required
“[e]xperience in a primary Federal law enforcement
position.” See J.A. 351–53. Nor did it implicitly indicate
that the requisite experience pertained to work related to
the unique duties of an individual in a Retrospective
CBPO Position—i.e., work directly connected with activi-
ties relating to the arrival and departure of persons,
conveyances, and merchandise at ports of entry. See id.;
5 C.F.R. § 842.1003(c)(1). Indeed, as the job title suggest-
FITZGERALD   v. DHS                                     21



ed—Law Enforcement Specialist (Instructor)—the listed
duties reflect those of someone with prior law-
enforcement experience, not necessarily experience in
customs and border protection. See J.A. 351–53. Alt-
hough Ms. Fitzgerald might train a “wide variety” of
employees in law enforcement (including CBPOs), and
although she might have obtained the Initial Position
only by virtue of her prior service in Retrospective CBPO
Positions at INS and Customs, that does not establish
that her experience in those positions was a “mandatory
prerequisite,” as required under the regulations. Instead,
it merely indicates that some overlap likely exists be-
tween the knowledge and experience required for the
Initial Position and that gained by Ms. Fitzgerald while
working in those positions.
    Accordingly, we conclude that the Board’s decision
that Ms. Fitzgerald’s prior service did not meet the crite-
ria of § 842.1003(b) and that she therefore is not entitled
to CBPO retirement credit for her time at FLETC is
supported by substantial evidence.
                       CONCLUSION
    We hold that 5 C.F.R. §§ 842.1002 and 842.1003(c)(2)
are not invalid, because they do not impermissibly con-
tradict the plain language or purpose of 5 U.S.C. § 8401
and because they are based on a permissible construction
of the statute. We also hold that the Board’s final deci-
sion, which affirmed the Agency’s denial of Ms. Fitzger-
ald’s request for retirement credit, is supported by
substantial evidence. We therefore affirm the final deci-
sion.
                      AFFIRMED
                          COSTS
   Each party shall bear its own costs.
