  United States Court of Appeals
      for the Federal Circuit
                ______________________

                  JAMES L. KISOR,
                  Claimant-Appellant

                           v.

 DAVID J. SHULKIN, SECRETARY OF VETERANS
                   AFFAIRS,
              Respondent-Appellee
             ______________________

                      2016-1929
                ______________________

   Appeal from the United States Court of Appeals for
Veterans Claims in No. 14-2811, Judge Alan G. Lance, Sr.
                ______________________

              Decided: September 7, 2017
                ______________________

   KENNETH M. CARPENTER, Law Offices of Carpenter
Chartered, Topeka, KS, argued for claimant-appellant.

    IGOR HELMAN, Commercial Litigation Branch, Civil
Division, United States Department of Justice, Washing-
ton, DC, argued for respondent-appellee. Also represent-
ed by BENJAMIN C. MIZER, ROBERT E. KIRSCHMAN, JR.,
MARTIN F. HOCKEY, JR.; Y. KEN LEE, SAMANTHA ANN
SYVERSON, United States Department of Veterans Affairs,
Washington, DC.
                 ______________________
2                                          KISOR   v. SHULKIN



    Before REYNA, SCHALL, and WALLACH, Circuit Judges.
SCHALL, Circuit Judge.
    James L. Kisor, a veteran, appeals the January 27,
2016 decision of the United States Court of Appeals for
Veterans Claims (“Veterans Court”) in Kisor v. McDonald,
No. 14-2811, 2016 WL 337517 (Vet. App. Jan. 27, 2016).
In that decision, the Veterans Court affirmed the April
29, 2014 decision of the Board of Veterans’ Appeals
(“Board”) denying Mr. Kisor entitlement to an effective
date earlier than June 5, 2006, for the grant of service
connection for his post-traumatic stress disorder
(“PTSD”). Kisor, 2016 WL 337517, at *1. We affirm.
                       BACKGROUND
                             I.
    The pertinent facts are as follows: Mr. Kisor served
on active duty in the Marine Corps from 1962 to 1966. Id.
In December of 1982, he filed an initial claim for disabil-
ity compensation benefits for PTSD with the Department
of Veterans Affairs (“VA”) Regional Office (“RO”) in Port-
land, Oregon. Id. Subsequently, in connection with that
claim, the RO received a February 1983 letter from David
E. Collier, a counselor at the Portland Vet Center.
J.A. 17. In his letter, Mr. Collier stated: “[I]nvolvement
in group and individual counseling identified . . . concerns
that Mr. Kisor had towards depression, suicidal thoughts,
and social withdraw[a]l. This symptomatic pattern has
been associated with the diagnosis of Post-Traumatic
Stress Disorder (DSM III 309.81).” Id.
    In March of 1983, the RO obtained a psychiatric ex-
amination for Mr. Kisor. In his report, the examiner
noted that Mr. Kisor had served in Vietnam; that he had
KISOR   v. SHULKIN                                          3



participated in “Operation Harvest Moon” 1; that he was
on a search operation when his company came under
attack; that he reported several contacts with snipers and
occasional mortar rounds fired into his base of operation;
and that he “was involved in one major ambush which
resulted in 13 deaths in a large company.” J.A. 19–20.
The examiner did not diagnose Mr. Kisor as suffering
from PTSD, however. Rather, it was the examiner’s
“distinct impression” that Mr. Kisor suffered from “a
personality disorder as opposed to PTSD.” J.A. 21. The
examiner diagnosed Mr. Kisor with intermittent explosive
disorder and atypical personality disorder. Id. Such
conditions cannot be a basis for service connection. See 38
C.F.R. § 4.127. 2 Given the lack of a current diagnosis of
PTSD, the RO denied Mr. Kisor’s claim in May of 1983.
J.A. 23. The RO decision became final after Mr. Kisor
initiated, but then failed to perfect, an appeal. Kisor,
2016 WL 337517, at *1.
                             II.
    On June 5, 2006, Mr. Kisor submitted a request to re-
open his previously denied claim for service connection for
PTSD. J.A. 25. While his request was pending, he pre-
sented evidence to the RO. This evidence included a July
20, 2007 report of a psychiatric evaluation diagnosing
PTSD. See J.A. 100–11. It also included a copy of
Mr. Kisor’s Department of Defense Form 214, a Combat


    1     Operation Harvest Moon was a military engage-
ment against the Viet Cong during the Vietnam War.
See, e.g., J.A. 20, 95, 101.
    2     Under § 4.127, “[i]ntellectual disability (intellec-
tual developmental disorder) and personality disorders
are not diseases or injuries for compensation purposes,
and . . . disability resulting from them may not be service-
connected.”
4                                         KISOR   v. SHULKIN



History, Expeditions, and Awards Record documenting
his participation in Operation Harvest Moon, and a copy
of the February 1983 letter from the Portland Vet Center.
See J.A. 16–17, 27–28. In September of 2007, a VA exam-
iner diagnosed Mr. Kisor with PTSD. J.A. 115. The RO
subsequently made a Formal Finding of Information
Required to Document the Claimed Stressor based on
Mr. Kisor’s statements, his service medical records (which
verified his service in Vietnam with the 2nd Battalion,
7th Marines), and a daily log from his unit, which detailed
the combat events Mr. Kisor had described in connection
with his claim. J.A. 30.
    In due course, the RO issued a rating decision reopen-
ing Mr. Kisor’s previously denied claim. The decision
granted Mr. Kisor service connection for PTSD and as-
signed a 50 percent disability rating, effective June 5,
2006. 3 Kisor, 2016 WL 337517, at *1. According to the



    3    Pursuant to 38 C.F.R. § 3.156(a), a claim may be
reopened on the submission of “new and material” evi-
dence. The regulation defines “new” evidence as “existing
evidence not previously submitted to agency decisionmak-
ers.” 38 C.F.R. § 3.156(a). It defines “material” evidence
as “existing evidence that, by itself or when considered
with previous evidence of record, relates to an unestab-
lished fact necessary to substantiate the claim.” Id. If a
previously denied claim (such as Mr. Kisor’s PTSD claim)
is later reopened and granted based on the submission of
new and material evidence, the effective date of benefits
is the date that the claimant filed the application to
reopen or the date entitlement arose, whichever is later.
See 38 U.S.C. § 5110(a); 38 C.F.R. § 3.400(q)(2). In this
case, under the new and material evidence approach, the
effective date for benefits would be June 5, 2006—the
date of Mr. Kisor’s request to reopen his claim. J.A. 25.
KISOR   v. SHULKIN                                        5



decision, the rating was based upon evidence that includ-
ed the July 2007 psychiatric evaluation report diagnosing
PTSD, the September 2007 VA examination, and the
Formal Finding of Information Required to Document the
Claimed Stressor. J.A. 32–33. The RO explained that
service connection was warranted because the VA exami-
nation showed that Mr. Kisor was diagnosed with PTSD
due to experiences that occurred in Vietnam and because
the record showed that he was “a combat veteran (Combat
Action Ribbon recipient).” J.A. 33.
     In November of 2007, Mr. Kisor filed a Notice of Disa-
greement. In it, he challenged both the 50 percent disa-
bility rating and the effective date assigned by the RO.
Kisor, 2016 WL 337517, at *1. Subsequently, in March of
2009, the RO issued a decision increasing Mr. Kisor’s
schedular rating to 70 percent. In addition, the RO
granted a 100 percent rating on an extraschedular basis,
effective June 5, 2006. 4 J.A. 41–45. In January of 2010,
the RO issued a Statement of the Case denying entitle-
ment to an earlier effective date for the grant of service
connection for PTSD. See J.A. 53–65.




   4    The VA evaluates a veteran’s disability level by
using diagnostic codes in the rating schedule of title 38 of
the Code of Federal Regulations. See 38 C.F.R. § 3.321(a);
see generally 38 C.F.R. §§ 4.40–4.150 (rating schedule).
The evaluation reflects a veteran’s base, “schedular”
rating. See Thun v. Peake, 22 Vet. App. 111, 114 (2008).
In exceptional cases, where the schedular rating is inade-
quate, the veteran is eligible for a higher, “extraschedu-
lar” disability rating. See 38 C.F.R. § 3.321(b)(1); Thun,
22 Vet. App. at 114–15.
6                                           KISOR   v. SHULKIN



                             III.
    Mr. Kisor appealed to the Board. Before the Board,
he contended that he was entitled to an effective date
earlier than June 5, 2006 for the grant of service connec-
tion for PTSD. Specifically, he argued that the proper
effective date for his claim was the date of his initial claim
for disability compensation that was denied in May of
1983. See J.A. 47–48. In support, Mr. Kisor alleged clear
and unmistakable error (CUE) in the May 1983 rating
decision; he also alleged various duty-to-assist failures on
the part of the VA. See J.A. 47–48, 84–87.
     The Board rejected these arguments. It ruled that the
duty to assist had not been violated, that Mr. Kisor had
failed to establish CUE, and that the RO’s May 1983
rating decision became final when Mr. Kisor failed to
perfect his appeal of the decision. See J.A. 85–88. The
Board found no reason to upset the finality of the May
1983 decision because “[t]he remedy available to the
Veteran was to appeal,” but he did not do so. J.A. 86.
    The Board, however, raised “another way to challenge
the May 1983 rating decision” that had not been advanced
by Mr. Kisor. J.A. 88. That way turned on whether
Mr. Kisor was eligible for an earlier effective date for his
service connection under the regulation set forth at 38
C.F.R. § 3.156(c). In contrast to 38 C.F.R. § 3.156(a),
which only permits claims to be reopened on the submis-
sion of “new and material” evidence, § 3.156(c) allows
claims to be reconsidered if certain conditions are met.
See 38 C.F.R. § 3.156(c)(1) (noting that § 3.156(c) applies
“notwithstanding paragraph (a)”).
    Subsection 3.156(c) includes two parts relevant to this
appeal. First, paragraph (c)(1) defines the circumstances
under which the VA must reconsider a veteran’s claim for
benefits based on newly-associated service department
records:
KISOR   v. SHULKIN                                          7



    [A]t any time after VA issues a decision on a
    claim, if VA receives or associates with the claims
    file relevant official service department records
    that existed and had not been associated with the
    claims file when VA first decided the claim, VA
    will reconsider the claim . . . .
38 C.F.R. § 3.156(c)(1). Second, paragraph (c)(3) estab-
lishes the effective date for any benefits granted as a
result of reconsideration under paragraph (c)(1):
    An award made based all or in part on the records
    identified by paragraph (c)(1) of this section is ef-
    fective on the date entitlement arose or the date
    the VA received the previously decided claim,
    whichever is later, . . . .
38 C.F.R. § 3.156(c)(3).
    Section 3.156(c) thus provides for an effective date for
claims that are reconsidered that is different from the
effective date for claims that are reopened. As we pointed
out in Blubaugh v. McDonald, “[i]n contrast to the general
rule, § 3.156(c) requires the VA to reconsider a veteran’s
claim when relevant service department records are
newly associated with the veteran’s claims file, whether
or not they are ‘new and material’ under § 3.156(a).” 773
F.3d 1310, 1313 (Fed. Cir. 2014) (citing New and Material
Evidence, 70 Fed. Reg. 35,388, 35,388 (June 20, 2005)).
“In other words,” we observed, “§ 3.156(c) serves to place a
veteran in the position he would have been in had the VA
considered the relevant service department record before
the disposition of his earlier claim.” Id.
    Applying the regulation, the Board considered wheth-
er the material Mr. Kisor submitted in connection with
his June 2006 request to reopen warranted reconsidera-
8                                         KISOR   v. SHULKIN



tion of his claim. 5 If it did, then Mr. Kisor would have
been eligible for an effective date of December of 1982 for
his disability benefits, “the date the VA received the
previously decided claim.” 38 C.F.R. § 3.156(c)(3).
    After reviewing the evidence, the Board denied
Mr. Kisor entitlement to an effective date earlier than
June 5, 2006. J.A. 91. The Board found that the VA did
receive service department records documenting
Mr. Kisor’s participation in Operation Harvest Moon after
the May 1983 rating decision. J.A. 89–90. The Board
concluded, though, that the records were not “relevant”
for purposes of § 3.156(c)(1). J.A. 90. The Board ex-
plained that the 1983 rating decision denied service
connection because there was no diagnosis of PTSD, and
because service connection can be granted only if there is
a current disability. 6 Id. (citing Brammer v. Derwinski, 3
Vet. App. 223 (1992)). The Board stated that “relevant
evidence, whether service department records or other-
wise, received after the rating decision would suggest or
better yet establish that the Veteran has PTSD as a
current disability.” Id. The Board noted that Mr. Kisor’s
“service personnel records and the daily log skip this
antecedent to address the next service connection re-



    5   The newly-submitted material related to
Mr. Kisor’s Marine Corps service in Vietnam, including
his participation in Operation Harvest Moon. J.A. 94–97.
These records had not been part of Mr. Kisor’s claims file
in May of 1983 when the RO first denied his claim.
    6   Service connection for PTSD requires (1) a medi-
cal diagnosis of the condition, (2) a medically established
link between current symptoms and an in-service stress-
or, and (3) credible evidence showing that the in-service
stressor occurred.     See 38 C.F.R. § 3.304(f); Golz v.
Shinseki, 590 F.3d 1317, 1321–22 (Fed. Cir. 2010).
KISOR   v. SHULKIN                                         9



quirement of a traumatic event during service.” Id.
Finally, the Board concluded with the observation that
the records at issue were not “outcome determinative” and
“not relevant to the decision in May 1983 because the
basis of the denial was that a diagnosis of PTSD was not
warranted, not a dispute as to whether or not the Veteran
engaged in combat with the enemy during service.”
J.A. 90–91.
    Mr. Kisor appealed the Board’s decision to the Veter-
ans Court. There, he argued that the Board had “failed to
consider and apply the provisions of 38 C.F.R. § 3.156(c).” 7
Kisor, 2016 WL 337517, at *1. The court rejected the
argument. The court noted that Mr. Kisor did not argue
that the service department records presented after the
May 1983 rating decision contained a diagnosis of PTSD,
the absence of such a diagnosis having been the basis for
the RO’s 1983 rating decision. Id. at *2. The Veterans
Court stated that it was “not persuaded that the Board
incorrectly applied § 3.156.” Id. at *3. Accordingly, it
held that Mr. Kisor had “failed to demonstrate error in
the Board’s findings that an effective date earlier than
June 5, 2006, is not warranted for the grant of service




    7   Mr. Kisor’s appeal to the Veterans Court focused
solely on the Board’s purported misinterpretation of 38
C.F.R. § 3.156(c)(1). Mr. Kisor did not pursue his CUE or
duty-to-assist claims before the Veterans Court, and he
has not raised them before us. We therefore consider
them waived. See, e.g., Emenaker v. Peake, 551 F.3d
1332, 1337 (Fed. Cir. 2008) (considering an argument
waived on appeal when it was not timely presented to the
Veterans Court); SmithKline Beecham Corp. v. Apotex
Corp., 439 F.3d 1312, 1319 (Fed. Cir. 2006) (“[A]rguments
not raised in the opening brief are waived.”).
10                                           KISOR   v. SHULKIN



connection for PTSD.” Id. Mr. Kisor timely appealed the
Veterans Court’s decision.
                         DISCUSSION
                              I.
    Section 7292 of title 38 of the United States Code
grants us jurisdiction over decisions of the Veterans
Court. Section 7292 provides that we “‘shall decide all
relevant questions of law’ arising from appeals from
decisions of the Veterans Court, but, ‘[e]xcept to the
extent that an appeal . . . presents a constitutional issue,
[we] may not review (A) a challenge to a factual determi-
nation, or (B) a challenge to a law or regulation as applied
to the facts of a particular case.’” Sneed v. McDonald, 819
F.3d 1347, 1350–51 (Fed. Cir. 2016) (quoting 38 U.S.C.
§ 7292(d)(1)–(2)).
    As discussed more fully below, on appeal Mr. Kisor
argues that the Veterans Court misinterpreted 38 C.F.R.
§ 3.156(c)(1). An argument that the Veterans Court
misinterpreted a regulation falls within our jurisdiction.
See 38 U.S.C. § 7292(c) (granting this court “exclusive
jurisdiction to review and decide any challenge to the
validity of any . . . regulation or any interpretation there-
of” by the Veterans Court); Spicer v. Shinseki, 752 F.3d
1367, 1369 (Fed. Cir. 2014); Githens v. Shinseki, 676 F.3d
1368, 1371 (Fed. Cir. 2012).
    We must set aside an interpretation of a regulation
that we find to be:
     (A) arbitrary, capricious, an abuse of discretion, or
     otherwise not in accordance with law;
     (B) contrary to constitutional right, power, privi-
     lege, or immunity;
     (C) in excess of statutory jurisdiction, authority,
     or limitations, or in violation of a statutory right;
     or
KISOR   v. SHULKIN                                         11



    (D) without observance of procedure required by
    law.
38 U.S.C. § 7292(d)(1)(A)–(D); Sursely v. Peake, 551 F.3d
1351, 1354 (Fed. Cir. 2009).
                             II.
    Mr. Kisor contends that, in affirming the decision of
the Board, the Veterans Court erred in its interpretation
of 38 C.F.R. § 3.156(c)(1). 8 As seen, the regulation pro-



    8      Mr. Kisor never argued before the Veterans Court
that the Board misinterpreted the term “relevant” in
§ 3.156(c).      See J.A. 117–29 (Opening Brief), 155–65
(Reply Brief). Instead, as noted, he argued that the Board
“failed to consider and apply the provisions
of . . . § 3.156(c).” J.A. 123; see J.A. 128 (raising “a ques-
tion of regulatory interpretation” regarding whether “the
use of the phrase ‘that existed’ [in § 3.156(c)(1)] mean[s]
that the relevant official service department records must
have existed when the VA first decided the claim”).
Mr. Kisor’s failure to challenge the Board’s interpretation
of “relevant” before the Veterans Court could constitute
waiver. See Emenaker, 551 F.3d at 1337 (“In order to
present a legal issue in a veteran’s appeal, the appellant
ordinarily must raise the issue properly before the Veter-
ans Court . . . .”). The Board did determine, however, that
the “service department records received . . . were not
relevant.” J.A. 79; see J.A. 91 (stating that “those docu-
ments were not relevant to the [VA’s] decision” denying
his 1982 claim); see also J.A. 147 (VA Response Brief
before the Veterans Court explaining that the Board
determined that the service records were not relevant).
And at oral argument before us, the government aban-
doned its contention that Mr. Kisor had waived his argu-
ment regarding the interpretation of § 3.156(c)(1). Oral
12                                         KISOR   v. SHULKIN



vides that the VA will “reconsider” a claim if it “receives
or associates with the claims file relevant official service
department records that existed and had not been associ-
ated with the claims file when VA first decided the claim.”
38 C.F.R. § 3.156(c)(1) (emphasis added). Mr. Kisor states
that the VA should have reconsidered his claim under the
regulation and thus afforded him the favorable effective
date treatment that the regulation provides. He argues
that the Veterans Court, like the Board, “mistakenly
interpreted the term ‘relevant’ as used in 38 C.F.R.
§ 3.156(c)(1) as related only to service department records
that countered the basis of the prior denial.” Appellant’s
Br. 5.     In making this argument, he points to
§ 3.156(c)(1)(i), which provides in part that service de-
partment records “include, but are not limited to: . . .
[s]ervice records that are related to a claimed in-service
event, injury, or disease, regardless of whether such
records mention the veteran by name, as long as the other
requirements of [subsection] (c) of this section are met.” 9
Appellant’s Br. 8–9. Stating that nothing in the regula-
tion “says that the service records must relate to the
reason for the last denial,” Mr. Kisor urges that a service
department record is relevant if it has “any tendency to
make the existence of any fact that is of consequence to the
determination of the action more probable or less probable
than it would be without the evidence.” Appellant’s


Argument at 18:47–21:30 (No. 16-1929), http://
oralarguments.cafc.uscourts.gov/default.aspx?fl=
2016-1929.mp3. Accordingly, we decline to find waiver
here. See Singleton v. Wulff, 428 U.S. 106, 121 (1976)
(stating that waiver is an issue “left primarily to the
discretion of the courts of appeals”).
    9   There is no dispute that the personnel records at
issue in this case are “service records” within the meaning
of 38 C.F.R. § 3.156(c)(1)(i).
KISOR   v. SHULKIN                                      13



Br. 9–10 (quoting Counts v. Brown, 6 Vet. App. 473, 476
(1994)).   According to Mr. Kisor, the newly-provided
service department records demonstrate that he was
subjected to the trauma of combat, thereby establishing
his exposure to an in-service stressor. Id. at 10–13.
    The government responds that the Veterans Court
and the Board did not misinterpret § 3.156(c)(1). The
government takes the position that whether a service
department record is relevant depends upon the particu-
lar claim and the other evidence of record. Appellee’s
Br. 14. Thus, the government posits, “if a record is one
that the VA had no obligation to consider because it would
not have mattered in light of the other evidence, then it
cannot trigger reconsideration.” Id. at 15.
    Turning to the case at hand, the government states
that the records based upon which Mr. Kisor seeks recon-
sideration under § 3.156(c)(1) address only the issue of
whether there was an in-service stressor, not the requisite
medical diagnosis of PTSD. Id. at 17. The government
states: “The issue of an in-service stressor was never
disputed in the 1983 claim; in fact, the examiner noted
that Mr. Kisor participated in Operation Harvest Moon
and ‘was involved in one major ambush which resulted in
13 deaths in a large company.’” Id. (citing J.A. 19–20).
Accordingly, the government argues that none of the
service department records at issue were relevant under
the regulation because they related to the existence of an
in-service stressor, which was not in dispute, rather than
to a diagnosis of PTSD, the absence of which was the
basis for the RO’s denial of Mr. Kisor’s claim in 1983. Id.
at 17–18.
    Finally, the government urges us to reject Mr. Kisor’s
argument that the Veterans Court and the Board con-
strued the regulation too narrowly because they inter-
preted relevance as “related only to records that
countered the basis of the prior denial.” Id. at 18 (citing
14                                         KISOR   v. SHULKIN



Appellant’s Br. 5). The government contends that neither
tribunal required that the evidence relate to the basis for
the prior denial in all cases. Id. at 18–19. Rather, the
evidence simply has to be “relevant.” The government
concludes that “[i]t just so happened that in the present
case, evidence related to the in-service stressor could not
be relevant without a medical diagnosis for PTSD at the
time of the previous claim.” Id. at 19.
                            III.
     For the following reasons, we hold that the Veterans
Court did not misinterpret § 3.156(c)(1). We therefore
affirm the court’s decision affirming the Board’s decision
denying Mr. Kisor entitlement to an effective date earlier
than June 5, 2006, for the grant of service connection for
PTSD.
    At the heart of this appeal is Mr. Kisor’s challenge to
the VA’s interpretation of the term “relevant” in 38 C.F.R.
§ 3.156(c)(1). 10 As a general rule, we defer to an agency’s
interpretation of its own regulation “as long as the regula-
tion is ambiguous and the agency’s interpretation is
neither plainly erroneous nor inconsistent with the regu-
lation.” Gose v. U.S. Postal Serv., 451 F.3d 831, 836 (Fed.
Cir. 2006) (citing Gonzales v. Oregon, 546 U.S. 243 (2006);
Christensen v. Harris Cty., 529 U.S. 576, 588 (2000);
Bowles v. Seminole Rock & Sand Co., 325 U.S. 410, 413–
14 (1945)); see also Long Island Care at Home, Ltd. v.



     10 The Board interpreted 38 C.F.R. § 3.156(c)(1)
when it ruled that Mr. Kisor’s service department records
were not “relevant” under that subsection. See J.A 90–91.
Because the Board is part of the VA, see 38 U.S.C.
§ 7101(a); Henderson ex rel. Henderson v. Shinseki, 562
U.S. 428, 431 (2011), the Board’s interpretation of the
regulation is deemed to be the agency’s interpretation.
KISOR   v. SHULKIN                                       15



Coke, 551 U.S. 158, 171 (2007) (“[A]n agency’s interpreta-
tion of its own regulations is controlling unless plainly
erroneous or inconsistent with the regulations being
interpreted.” (internal quotation marks omitted) (quoting
Auer v. Robbins, 519 U.S. 452, 461 (1997))).
    We hold that § 3.156(c)(1) is ambiguous as to the
meaning of the term “relevant.” In our view, the regula-
tion is vague as to the scope of the word, and canons of
construction do not reveal its meaning. See Gose, 451
F.3d at 839 (ruling that a regulatory phrase is ambiguous
when “the regulation is vague as to the scope of the
phrase”); Cathedral Candle Co. v. Int’l Trade Comm’n,
400 F.3d 1352, 1362 (Fed. Cir. 2005) (holding a statute
ambiguous when “traditional tools of statutory construc-
tion” did not resolve the construction dispute). Signifi-
cantly, § 3.156(c)(1) does not specify whether “relevant”
records are those casting doubt on the agency’s prior
rating decision, those relating to the veteran’s claim more
broadly, or some other standard. This uncertainty in
application suggests that the regulation is ambiguous.
See, e.g., Abbott Labs. v. United States, 573 F.3d 1327,
1331 (Fed. Cir. 2009) (holding the regulatory term “affect”
was ambiguous when the regulation did not specify the
types of effects falling within its scope).
    The varying, alternative definitions of the word “rele-
vant” offered by the parties further underscore
§ 3.156(c)(1)’s ambiguity. See Nat’l R.R. Passenger Corp.
v. Bos. & Me. Corp., 503 U.S. 407, 418 (1992) (“The exist-
ence of alternative dictionary definitions . . . , each mak-
ing some sense under the statute, itself indicates that the
statute is open to interpretation.”); Hymas v. United
States, 810 F.3d 1312, 1320–21 (Fed. Cir. 2016). In his
briefs, Mr. Kisor defines “relevant” in a way mirroring the
federal rules of evidence. Compare Appellant’s Br. 9–10
(defining “relevant” as “any tendency to make the exist-
ence of any fact that is of consequence to the determina-
tion of the action more [or less] probable” (emphasis
16                                         KISOR   v. SHULKIN



omitted)), with Fed. R. Evid. 401(a)–(b) (defining “rele-
vant” as “any tendency to make a fact more or less proba-
ble” when the “fact is of consequence in determining the
action”). Mr. Kisor thus posits that his personnel records
are “relevant” because they speak to the presence of an in-
service stressor, one of the requirements of compensation
for an alleged service-connected injury. See 38 C.F.R.
§ 3.304(f).
     The government, in contrast, collects various compet-
ing definitions from case law, legal dictionaries, and legal
treatises. See Appellee’s Br. 14–15 (defining “relevant”
as, inter alia, “bearing upon or properly applying to the
matter at hand,” and “[l]ogically connected and tending to
prove or disprove a matter in issue” (emphasis added)
(citing Forshey v. Principi, 284 F.3d 1335, 1351 (Fed. Cir.
2002) (en banc); Relevant, BLACK’S LAW DICTIONARY (10th
ed. 2014))). These definitions support the government’s
argument that, in this case, Mr. Kisor’s personnel records
were not “relevant” because they addressed the matter of
an in-service stressor, which was not “in issue,” rather
than the issue of whether he suffered from PTSD, which
was “in issue.” Both parties insist that the plain regula-
tory language supports their case, and neither party’s
position strikes us as unreasonable. We thus conclude
that the term “relevant” in § 3.156(c)(1) is ambiguous. See
Viraj Grp. v. United States, 476 F.3d 1349, 1355–56 (Fed.
Cir. 2007) (ruling that a “regulation is ambiguous on its
face” when competing definitions for a disputed term
“seem reasonable”); Info. Tech. & Applications Corp. v.
United States, 316 F.3d 1312, 1320–21 (Fed. Cir. 2003).
    Because § 3.156(c)(1) is ambiguous, the only remain-
ing question is whether the Board’s interpretation of the
regulation is “plainly erroneous or inconsistent” with the
VA’s regulatory framework. Long Island, 551 U.S. at 171.
As seen, the Board reasoned that Mr. Kisor’s supple-
mental personnel records were not relevant because they
contained information that (1) was already known,
KISOR   v. SHULKIN                                      17



acknowledged, and undisputed in the RO’s 1983 decision,
and (2) did not purport to affect the outcome of that
decision. J.A. 90–91. The Board’s ruling was thus based
upon the proposition that, as used in § 3.156(c)(1), “rele-
vant” means noncumulative and pertinent to the matter
at issue in the case. The Board’s interpretation does not
strike us as either plainly erroneous or inconsistent with
the VA’s regulatory framework.
    In this case, the records Mr. Kisor submitted to the
RO in 2006 detailing his participation in Operation Har-
vest Moon were superfluous to the information already
existing in his file. Indeed, in 1983 the VA examiner
expressly recounted how Mr. Kisor experienced “one
major ambush which resulted in 13 deaths in a large
company,” and that “[t]his occurred during Operation
Harvest Moon.” J.A. 19–20 (emphasis added). In addi-
tion, Mr. Kisor’s personnel records submitted in 2006 are
not probative here because they do not purport to remedy
the defects of his 1982 PTSD claim. The RO denied
Mr. Kisor’s PTSD claim because the requisite diagnosis of
PTSD was lacking. J.A. 21–23; see 38 C.F.R. § 3.304(f)
(requiring a diagnosis of PTSD to establish service con-
nection); Young v. McDonald, 766 F.3d 1348, 1354 (Fed.
Cir. 2014) (“[T]he VA has long required a medical diagno-
sis of PTSD to establish service connection.”). Mr. Kisor
does not urge that the 2006 records provide that diagno-
sis. See Appellant’s Br. 5–6. Instead, the records show
that Mr. Kisor was exposed to an in-service stressor—a
wholly separate element for establishing service connec-
tion that, critically, was never at issue in the case. J.A.
19–20. Because Mr. Kisor’s 2006 records did not remedy
the defects of his 1982 claim and contained facts that
were never in question, we see no plain error in the
Board’s conclusion that the records were not “relevant” for
purposes of § 3.156(c)(1). See Blubaugh, 773 F.3d at 1314
(reasoning that § 3.156(c) did not apply when service
records “did not remedy [the] defects” of a prior rating
18                                         KISOR   v. SHULKIN



decision and contained facts that “were never in ques-
tion”).
    Finally, as noted, Mr. Kisor argues that the Board
and Veterans Court construed § 3.156(c)(1) too narrowly,
by interpreting “relevant” records to be “records that
countered the basis of the prior denial [of benefits].”
Appellant’s Br. 5. We do not agree with this reading of
the Board’s or the Veterans Court’s decision. Nothing in
either tribunal’s interpretation of § 3.156(c)(1) strikes us
as requiring, across the board, that relevant records must
relate to the basis of a prior denial. Rather, we under-
stand the Board and Veterans Court as finding only that,
on the facts and record of this case, Mr. Kisor’s later-
submitted materials were not relevant to determination of
his claim. See Kisor, 2016 WL 337517, at *2–3.
                       CONCLUSION
     For the foregoing reasons, we see no error in the
Board’s interpretation of § 3.156(c)(1) or in the Veterans
Court’s affirmance of the Board’s interpretation. See
Kisor, 2016 WL 337517, at *2. The decision of the Veter-
ans Court affirming the Board’s decision denying
Mr. Kisor entitlement to an effective date earlier than
June 5, 2006 for service connection for PTSD is therefore
affirmed.
                       AFFIRMED
                          COSTS
     No costs.
