 United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT

Argued January 11, 2016           Decided February 23, 2016

                        No. 14-1055

               NBCUNIVERSAL MEDIA, LLC,
                     PETITIONER

                             v.

           NATIONAL LABOR RELATIONS BOARD,
                     RESPONDENT


                 Consolidated with 14-1080


       On Petition for Review and Cross-Application
        for Enforcement of a Decision and Order of
            the National Labor Relations Board


    Paul A. Salvatore argued the cause for petitioner. On the
briefs were Bernard M. Plum, Michael J. Lebowich, and
Daniel Jerome Davis.

   Gregoire Sauter, Attorney, National Labor Relations
Board, argued the cause for respondent. With him on the brief
were Richard F. Griffin, Jr., General Counsel, John H.
Ferguson, Associate General Counsel, Linda Dreeben,
Deputy Associate General Counsel, and Robert J. Englehart,
Supervisory Attorney. Amy H. Ginn, Attorney, entered an
appearance.
                               2
  Before: TATEL and MILLETT, Circuit Judges, and
EDWARDS, Senior Circuit Judge.

  Opinion for the Court filed by Senior Circuit Judge
EDWARDS.

    EDWARDS, Senior Circuit Judge: NBCUniversal Media,
LLC (“NBC” or the “Company”) petitions for review of a
2014 Decision and Order of the National Labor Relations
Board (“NLRB” or the “Board”). The Board cross-petitions
for enforcement. Because, as described below, we are unable
to discern the rationale underlying a significant portion of the
Board’s decision, we remand the case for clarification. We
mean to express no opinion on the merits. Rather, we are
remanding the case because we cannot meaningfully review
the Board’s decision as it now stands.

    In 2009 and 2010, the Board received unit clarification
petitions from the National Association of Broadcast
Employees & Technicians (“NABET” or the “Union”) and
several NABET local unions. The petitions requested that the
Board clarify that all NBC employees represented by NABET
under the parties’ 2006-2009 collective bargaining agreement
were part of a single, nationwide bargaining unit. The
petitions also sought to clarify that any persons assigned to
the newly created Content Producer position at NBC were
both covered by the agreement and were part of the
nationwide bargaining unit. The petitions were consolidated
and set for hearing. On October 26, 2011, the Board’s Acting
Regional Director for Region 2 (“ARD”) issued a decision
largely granting NABET’s unit clarification petitions. He
found that all NBC employees represented by the Union were
part of one nationwide bargaining unit and that the Content
Producer position should be included in that unit. Decision on
Unit Clarification Petitions (Oct. 26, 2011), reprinted in Joint
                              3
Appendix (“J.A.”) 548-631 (“Clarification Decision”). On
September 25, 2013, the Board denied NBC’s request for
review of the ARD’s decision. NBC then declined to bargain
over the terms and conditions of employment for Content
Producers.

    On October 28, 2013, NABET filed unfair labor practice
charges against NBC. On April 7, 2014, the Board issued a
Decision and Order finding that NBC had violated sections
8(a)(1) and (5) of the National Labor Relations Act, 29 U.S.C.
§ 158(a)(1) and (5), by failing and refusing to recognize and
bargain with the Union as the Content Producers’ exclusive
collective bargaining representative, and by failing to provide
the Union with information necessary to the fulfillment of its
duties. NBC Universal, Inc., 360 N.L.R.B. No. 69 (Apr. 7,
2014) (“ULP Decision”). The Board’s unfair labor practice
findings are largely based on the findings made by the ARD
in the Clarification Decision. The Company refused to
comply with the Board’s Order and filed a petition for review
with this court.

    NBC’s principal argument is that the Board erred in
adopting the findings of the ARD. NBC contends that the
Clarification Decision rests on the erroneous conclusion that
NABET represents a single, integrated bargaining unit at
NBC. According to NBC, Content Producers cannot be added
to a consolidated unit that does not exist. We cannot decipher
– either from the ARD’s decision or the Board’s decision
adopting the Clarification Decision – how the Board
determined that all NBC employees represented by NABET
are part of a single, nationwide bargaining unit. The
conclusion may or may not be right, but the reasoning
supporting the Board’s judgment – in particular, the ARD’s
application of Board precedent – is incomprehensible. When
an agency’s decision lacks adequate justification because it is
                               4
neither logical nor rational, or because it fails to offer a
coherent explanation of agency precedent, the judgment under
review is wanting for lack of reasoned decisionmaking. See,
e.g., Fox v. Clinton, 684 F.3d 67, 80 (D.C. Cir. 2012). In these
circumstances, we are constrained to remand the case to the
Board for further consideration and an opportunity to explain
the rationale supporting its judgment in a fashion that is
consistent with reasoned decisionmaking.

                      I.   BACKGROUND

A. Creation of the Content Producer Position

    The dispute in this case is a by-product of actions taken by
NBC in 2008 and 2009 to reorganize its production methods.
That reorganization resulted in the shift of work previously
assigned to employees working in positions covered by the
parties’ collective bargaining agreement to the Content
Producer position, which, at least as conceived by NBC, was
not a bargaining unit position.

     Creation of the Content Producer position was a critical
part of NBC’s overhaul of the news creation and delivery
systems at its local television stations. The Company
implemented its new model in “Content Centers” at local
NBC stations in New York, Chicago, and Los Angeles. The
initiative, which involved the creation of new job
classifications and the integration of new technology into
newly reorganized work spaces, facilitated a significant shift
in editorial focus from the production of broadcast television
news to the production of news content appropriate for
multiple platforms, including internet, cable, mobile devices,
and taxi-casts. NBC also created a Content Center in
Washington, D.C., but NABET representation of the Content
Producers at that location is not at issue here.
                                5

    Before the reorganization, various producers oversaw and
coordinated the production of broadcast news stories. These
producers worked closely with Camera Operators and Video
Editors to shoot, select, and assemble visual and audio
materials, and with Newswriters to create scripts. The Camera
Operators, Editors, and Newswriters were indisputably
covered by the 2006-2009 collective bargaining agreement
executed by NBC and NABET. Producers, however, were
excluded.

    According to the job description posted by NBC, persons
assigned to the newly created Content Producer position
“‘desktop edit, write, produce and gather content on all . . .
platforms’ and are ‘responsible for the overall coverage of
assigned stories on all platforms throughout the day.’”
Clarification Decision at 27, J.A. 574 (quoting Content
Producer Job Posting, reprinted in J.A. 521). And, according
to NBC’s Vice President of News and Content, Content
Producers have “‘ownership of a story’ which ‘could include
pitching an idea, it could include setting up the story; who’s
going to be interviewed, . . . [i]t could include going an [sic]
shooting the interview and the pictures for the story . . .
[w]riting the story, editing the story, writing the anchor intro
and tag for the story, creating a web version of the story,
pitching a taxi-cast iteration of the story.’” Id. (alterations and
ellipses in original) (quoting Transcript of Hearing 350
(testimony of Vickie Burns, NBC Vice President of News and
Content), reprinted in J.A. 48).

     Thus, while NBC conceived of the Content Producer
classification as a non-bargaining unit position, see Request
for Review by Respondent NBCUniversal Media, LLC 2
(Dec. 15, 2011), reprinted in J.A. 637, and Content Producers
are responsible for certain conceptual and supervisory tasks
                               6
that were performed by non-bargaining unit producers before
the Company’s reorganization, the position also includes
bargaining unit work traditionally performed by Editors,
Camera Operators, and Newswriters. And it is undisputed that
the number of Editor and Newswriter positions at NBC’s
local stations decreased dramatically, sometimes altogether
disappearing, as a result of the Company’s reorganization and
creation of the Content Producer positions. Indeed, NBC
actually recruited and hired a number of Content Producers
from within the ranks of its existing Editors and Newswriters.

B. The Collective Bargaining Agreement

    The Union and NBC have negotiated numerous collective
bargaining agreements during the course of their nearly 70-
year relationship. The agreement at issue in this case is the
NABET-CWA NBCU Master Agreement 2006-2009
(“Master Agreement”), reprinted in J.A. 206-519, which took
effect on April 1, 2006, and expired on March 31, 2009.

    The Master Agreement covers various job classifications
at NBC-owned stations in New York, Chicago, Los Angeles,
and Washington, D.C., and it explicitly states that the parties’
contract is “between NBC Universal, Inc., as the owner and
operator” of the covered TV and radio operations, “and the
National Association of Broadcast Employees and
Technicians, the Broadcasting and Cable Television Workers
Sector of the Communications Workers of America.” Master
Agreement at 1, J.A. 215. Neither NABET local unions nor
any other unions are referenced in the Master Agreement.

    The structure of the Master Agreement plays a pivotal role
in the parties’ dispute over whether it is meant to cover one
nationwide bargaining unit. The preamble to the Master
Agreement says that “the intent and purpose of the parties [is]
                              7
to set forth . . . the basic collective bargaining agreements
between [them] in two (2) parts.” Id. Those parts consist of:

   (I) GENERAL ARTICLES covering those subjects
   which are uniformly applicable to substantially all of
   the basic relationships, hours of work and general
   conditions of employment, including a procedure for
   prompt, equitable adjustment of grievances to the end
   that there shall be no work stoppages or other
   interferences with operations during the life of these
   Agreements; and

   (II) INDIVIDUAL ARTICLES which will contain
   the description of each bargaining unit, which shall not
   be affected hereby, the rates of pay and any unusual
   working conditions which have no general application.

Id. The preamble also provides that, “[i]n the event of any
conflict between the General and Individual Articles, the
Individual Articles will prevail.” Id.

    In addition to 26 General Articles and 15 Individual
Articles (each titled “Agreement” in the Table of Contents),
the Master Agreement contains numerous “Sideletters” that
supplement or modify the General and Individual Articles.

    The only signatories to the Master Agreement are
NABET’s President, John Clark, and NBC’s former Senior
Vice President of Labor Relations and Talent Negotiations,
Day Krolik. Id. at 57, J.A. 271. Their signatures appear at the
end of the General Articles. The Individual Articles and
Sideletters are not separately signed. And there is no evidence
that any NBC representatives of local stations or officials of
NABET local unions signed the Master Agreement.
                              8
  The first of the General Articles, Article I Recognition and
Warranty, provides:

    The Union represents and warrants, and it is of the
    essence hereof, that it represents for collective
    bargaining purposes all of the employees of the
    Company as defined in the applicable SCOPE OF
    UNIT clause, and the Company recognizes the Union
    as the exclusive bargaining agent for all such
    employees of the Company.

Id. at 1, J.A. 215. As noted in the preamble, the remainder of
the General Articles describe matters applicable to all
employees covered by the Master Agreement, including, inter
alia, work schedules and overtime; seniority, layoffs, and
rehiring; leaves of absence; discharges; severance pay;
vacations; and grievances and arbitration.

    The Individual Articles, together, identify all of the job
classifications or positions covered by the Master Agreement.
Individually, each Article describes the various wage rates
agreed to for the positions identified therein and any unusual
working conditions specific to those positions. With the
exceptions of Individual Article A (which encompasses all of
the many covered engineering and technical positions
regardless of location) and Individual Article D (which covers
“new businesses,” i.e., positions involving new work not
previously associated with a job classification), each
Individual Article covers positions specific to a particular
city. For example, Newswriters in Chicago, Los Angeles and
New York are covered by Individual Articles H, M, and N,
respectively.

    Some Individual Articles encompass many job
classifications, and some only one. Eleven of the fifteen
                               9
Individual Articles identify the positions or job classifications
covered in a subsection titled “Scope of Unit.” Four
Individual Articles do not contain Scope of Unit sections. One
of those, Individual Article D, as noted above, covers
positions involving new work not previously associated with a
job classification. The remaining three indicate (via an
incorporated Sideletter or agreement) that the job positions
previously identified in each had either been moved into
Individual Article A or eliminated as identifiable positions
subject to bargaining. Throughout the Master Agreement,
“unit,” “units,” “each bargaining unit,” and “any unit”
frequently stand in for or are used to reference groups of job
classifications identified in each Individual Article.

    There are three job classifications relevant to the Content
Producer position at issue here: Video Editor and Camera
Operator – both of which are covered by Individual Article A
– and Newswriter, a position covered by Individual Article N
for New York, H for Chicago, and M for Los Angeles.

C. Procedural Background

    On September 19, 2008, as NBC was preparing to
establish the first Content Center at WNBC New York, the
Company and NABET Local 11 entered into a written
agreement providing that, except for employees who had
occupied NABET-represented jobs and who chose to remain
represented by the Union, Content Producers at WNBC would
not be covered by the Master Agreement. See Agreement
(Sept. 19, 2008), reprinted in J.A. 522-24. The agreement also
stated that the Union “agrees that it will make no claims to
represent any non-NABET-represented Content Producers
employed by WNBC except in the event such employees elect
NABET-CWA as their bargaining agent in an election
supervised by the NLRB.” Id. at 3, J.A. 524.
                              10

    When NBC launched the Content Centers in Chicago and
Los Angeles, NABET locals in those cities refused to sign
agreements similar to the one signed by Local 11. Instead, the
Union and its locals (including Local 11) filed unfair labor
practice charges, as well as the petitions for clarification at
issue here. After initially pursuing the unfair labor practice
charges against NBC, the Board reversed the order of the
proceedings, held the unfair labor practice charges in
abeyance, and informed the parties that it would proceed with
the unit clarification petitions. See Request for Review by
Respondent NBCUniversal, LLC 2-4, J.A. 637-39.

    The Board subsequently consolidated the clarification
petitions, and a Board hearing officer took testimony over the
course of several weeks during a two-month period. On the
basis of that testimony, accompanying exhibits, and post-
hearing briefs, the ARD for Region 2 issued the Clarification
Decision that the Board adopted in its subsequent ULP
Decision.

    Before the ARD, the principal arguments advanced by
NABET and NBC were largely premised on their differing
views as to whether the NABET employees covered by the
2006-2009 Master Agreement belonged to a single,
nationwide bargaining unit, as NABET contended, or twelve
separate bargaining units defined by the Individual Articles,
as NBC asserted. See Clarification Decision at 54, J.A. 601.
NABET argued that if covered employees belonged to a
single, nationwide unit, application of the “same basic
functions” standard of Premcor, Inc., 333 N.L.R.B. 1365
(2001), was appropriate and would support a finding that
Content Producers belonged within the unit. See Clarification
Decision at 2, 67-68, J.A. 549, 614-15. NBC argued that the
“community-of-interest” accretion standard applied and,
                                 11
under that standard, the Content Producer position could not
be added to any of the extant bargaining units. See id.

    The ARD resolved the unit clarification question in
NABET’s favor, finding that all employees covered by the
Master Agreement constituted a single unit. In determining
which standard to apply to that single unit – the Premcor
analysis or the community-of-interest accretion analysis – the
ARD “recognize[d] that the instant case differs from
Premcor, in part because the Content Producers have some
responsibilities that do not appear to have been previously
performed by bargaining unit employees.” Id. at 70, J.A. 617.
Nonetheless, the ARD found that Premcor provided the most
appropriate standard, explaining:

      [A]pplication of a traditional accretion analysis here is
      problematic in light of [NBC’s] contention that such
      an analysis cannot compare the Content Producers
      with bargaining unit classifications that no longer
      exist. Clearly, “community of interest” factors such as
      interchange between unit employees and the new
      classification, supervision, and even functional
      integration, are rendered meaningless, or in any case
      are substantially compromised, in circumstances where
      the most relevant bargaining unit classifications, here
      Newswriters and Editors, have been eliminated as a
      result of the very change in [NBC’s] operations that
      produced the new classification. This was the case in
      Premcor, and it is also the case here.

Id.

    The ARD additionally rejected NBC’s argument that the
agreement signed by Local 11 was binding on NABET with
respect to Content Producers in New York. Id. at 62, J.A. 609.
                                12
On this point, the ARD found that “[t]here is nothing in the
NABET-CWA By-Laws tending to establish that Local Union
Presidents have authority to sign agreements with the
Employer concerning who will and will not fall within the
Union’s representation.” Id. The ARD further found that
“there is no evidence that NABET-CWA President Clark even
knew of Local 11 President McEwan’s negotiations with the
Employer, let alone designated Local 11 President McEwan
to negotiate in regard to the representation of the New York
Content Producers on the [sic] his behalf. . . . In short, there is
no evidence to warrant the conclusion that Mr. McEwan had
actual or apparent authority to bind the [Union] in regard to
the unit placement of the Content Producers.” Id. at 63, J.A.
610.

    NBC sought Board review of the ARD’s Clarification
Decision. The Board declined. See NBC Universal, Inc., 02-
UC-000619 et al. (Sept. 25, 2013), reprinted in J.A. 677. And
when NABET subsequently sought bargaining information
regarding the Content Producer position and attempted to
bargain with NBC over the position, NBC refused on the
ground that the Clarification Decision was wrongly decided.
NABET then filed unfair labor practice charges and, when
NBC persisted in refusing to bargain, the Board issued a
complaint on those charges. The Board’s General Counsel
filed a motion for summary judgment. NBC responded, again
arguing for review and reversal of the Clarification Decision.

    On April 7, 2014, the Board issued the ULP Decision at
issue here. Without elaboration, the Board adopted the ARD’s
Clarification Decision, stating:

    The employees described in the scope of unit clauses
    of the individual articles of the most recent master
    agreement between the Respondent and the Union . . .
                              13
   constitute a unit appropriate for the purposes of
   collective bargaining . . . within the meaning of
   Section 9(b) of the Act[, 29 U.S.C. 159(b)].

ULP Decision, 360 N.L.R.B. No. 69 at 2. Using similarly
concise language, the Board also adopted the ARD’s
conclusion “that [NBC’s] newly created position of content
producer at [its] New York, Chicago, and Los Angeles owned
and operated local stations was properly included in the unit.”
Id. Finally, describing the correspondence between the parties
regarding NBC’s refusal to provide information and bargain,
the Board concluded that NBC was engaging in unfair labor
practices, granted summary judgment against the Company,
and ordered NBC to recognize, provide information to, and
bargain with NABET. See id.at 2-4.

    NBC refused to comply with the Board’s order, and
petitioned this court for review. The Board cross-petitioned
for enforcement. This court has jurisdiction under sections
10(e) and (f) of the National Labor Relations Act. 29 U.S.C.
§ 160(e) and (f).

                      II. DISCUSSION

    NBC does not dispute that it refused to bargain with
NABET over the Content Producer position and that it also
refused to provide the Union with information about the new
job classification. In addition, the Company does not now
contest that if the Master Agreement encompasses a single,
nationwide bargaining unit, then the Premcor standard would
apply to determine whether the Content Producer position is
within the unit.

   NBC’s principal claim is that the Board’s ULP Decision
must be overturned because it rests on a flawed Clarification
                               14
Decision. In the Company’s view, the ARD erred in ignoring
and misreading clear and unambiguous language in the
parties’ Master Agreement, relying on extrinsic evidence,
misconstruing the history of the parties’ bargaining
relationship, and failing to properly consider and apply Board
precedent. The gravamen of NBC’s argument is that the ARD
improperly looked beyond the words of the Master
Agreement in determining whether employees covered by it
belonged to a single, nationwide bargaining unit or to multiple
individual units, and that he drew the wrong conclusion from
the extrinsic evidence that he considered.

A. Standard of Review

     The National Labor Relations Act delegates to the NLRB
the authority to “decide . . . whether, in order to assure to
employees the fullest freedom in exercising the[ir] rights[,]
. . . the unit appropriate for the purposes of collective
bargaining shall be the employer unit, craft unit, plant unit, or
subdivision thereof.” 29 U.S.C. § 159(b). The Supreme Court
long ago recognized that the Board’s “broad” discretion in
this area “reflect[s] Congress’ recognition ‘of the need for
flexibility in shaping the [bargaining] unit to the particular
case.’” NLRB v. Action Auto., Inc., 469 U.S. 490, 494 (1985)
(quoting NLRB v. Hearst Publ’ns, Inc., 322 U.S. 111, 134
(1944)). The “wide deference” afforded the Board in its unit
determinations also reflects the reality that each decision rests
on “a fact-intensive inquiry and a balancing of various
factors.” United Food & Commercial Workers, Local 540 v.
NLRB, 519 F.3d 490, 494 (D.C. Cir. 2008) (citation omitted);
see also Dodge of Naperville, Inc. v. NLRB, 796 F.3d 31, 38
(D.C. Cir. 2015).

   Because unit determinations involve such “a large
measure of informed discretion,” a Board decision, “if not
                              15
final, is rarely to be disturbed.” Packard Motor Car Co. v.
NLRB, 330 U.S. 485, 491 (1947). Congress has “delegate[d]
to the Board the responsibility to make a reasonable
determination supported by its own precedent and evidence in
the record. That this Court, or other reasonable people, may
prefer a bargaining unit with different contours is immaterial
as a reviewing court may not substitute its own judgment for a
rationally supported position adopted by the Board.” Country
Ford Trucks, Inc. v. NLRB, 229 F.3d 1184, 1189, (D.C. Cir.
2000) (citation omitted). In other words, we must uphold a
unit determination if it is supported by substantial evidence,
29 U.S.C. § 160(e)-(f), and is “rational and in accord with
past precedent,” Int’l Union of Elec., Radio & Mach.
Workers, 604 F.2d 689, 695 (D.C. Cir. 1979).

    The deference we owe the Board in determining the
appropriate size of a bargaining unit prevents us from
reviewing a Board determination on any rationale other than
the one supplied in its decision and order. See Point Park
Univ. v. NLRB, 457 F.3d 42, 49-50 (D.C. Cir. 2006). When
we cannot discern that rationale, we are in no better a position
than when the Board is silent. We cannot guess at what the
Board means to say for to do so would result in the court
improperly filling critical gaps in the Board’s reasoning and
perhaps sustaining the Board’s action on a ground that the
Board did not intend – something which is prohibited. See id.
at 50 (citing SEC v. Chenery Corp., 332 U.S. 194, 196-97
(1947)). In such situations, remand of the case for
clarification is a prerequisite to meaningful judicial review.
See Point Park Univ., 457 F.3d at 51; see also Detroit
Newspaper Agency v. NLRB, 435 F.3d 302, 304-05 (D.C. Cir.
2006) (stating that in the unlawful discharge context, “where
we cannot discern the precise basis upon which the Board
rested in reaching its conclusion, meaningful judicial review
                               16
requires us to remand the case to the Board for clarification”)
(ellipsis, alteration, and citation omitted).

B. The ARD’s Clarification Decision

    In analyzing whether employees represented by NABET
are part of a single, nationwide bargaining unit, the
Clarification Decision purports to apply or distinguish five
Board decisions. However, we are unable to follow the thread
of the decision’s reasoning at a number of critical points.
Most fundamentally, we are unable to discern the factual and
precedential bases for the ARD’s rigidly bifurcated approach
to assessing when and how to focus on the terms of the
Master Agreement, the structure of the agreement, and the
parties’ bargaining history in a unit clarification proceeding.

    As an initial matter, it is noteworthy that the Clarification
Decision says that because “[n]either party has introduced the
certification(s) of representation, which presumably would
contain a clear statement of the unit or units for which the
Union has been certified as the exclusive collective-
bargaining representative. . . . the parties’ agreement governs
the scope of the unit.” Clarification Decision at 54-55, J.A.
601-02 (citing La. Dock Co., 293 N.L.R.B. 233 (1989), enf’t.
denied on other grounds, 909 F.2d 281 (7th Cir. 1990)). The
ensuing discussion of this point is garbled, to say the least.

    Specifically, we do not know what to make of the ARD’s
footnoted acknowledgment that NABET did, in fact, point to
a Board decision certifying it as the representative of a
nationwide unit of NBC engineering and technical employees.
See Clarification Decision at 54 n.82, J.A. 601-02 (citing
Nat’l Ass’n of Broad. Eng’rs & Technicians, 59 N.L.R.B. 478
(1944)). The ARD says that this “tends to support the
                             17
Employer’s position that there exist multiple units, [but] the
case is not conclusive.” Id. The ARD then points out that

   the Board has found that even where parties have
   initially treated a group of employees at a particular
   location as a separate unit, the parties may
   subsequently establish a single national unit by a
   practice of joint bargaining, repeated negotiation of a
   national agreement, and other indicators of such
   intention. See Columbia Broadcasting System, Inc.,
   208 NLRB 825 (1974).

Clarification Decision at 54 n.82, J.A. 602. This line of
analysis is unilluminating because the Columbia Broadcasting
System (“CBS”) case involved a situation in which the
company and union established a bargaining relationship
pursuant to voluntary recognition. To make matters worse, the
ARD then states that, in this case, “it is unclear” whether
“(any of) the asserted unit(s) here” were established pursuant
to voluntary recognition. Id. at 54 n.83, J.A. 602. And the
ARD does not explain whether this has a bearing on the unit
clarification issue.

    We are thus at a loss to understand the Board’s view of
the effect of either the certification decision proffered by
NABET or the apparently indeterminate state of the record
with respect to agreements negotiated pursuant to voluntary
recognition. And the Clarification Decision offers no useful
analytical framework.

     In addition, we are unable to understand the precedential
basis for the ARD’s two-step, bifurcated approach to
determining the appropriate unit in a unit clarification
proceeding. Under the ARD’s approach, the parties’ history of
collective bargaining and the structure of their agreement are
                              18
not relevant unless the Board first finds that the literal terms
of the contract are ambiguous. We find little support in the
Board’s decisions for this bifurcated analysis.

     It is true that in Louisiana Dock, the Board, citing
Sambo’s Restaurants, Inc., 212 N.L.R.B. 788 (1974), said:
“When there is no clear and unambiguous contract provision
setting forth the parties’ agreement, it may be evidenced by
bargaining history or a pattern of bargaining.” 293 N.L.R.B.
at 234. However, the wholistic approach generally followed
by the Board in cases involving “master agreements” suggests
that the statement in Louisiana Dock may be permissive
(indicating how “bargaining history” may be useful), and not
restrictive as the ARD thought.

     There is no doubt here that the Master Agreement covers
all of the groups of job classifications identified in the
Individual Articles. This case is thus plainly distinguishable
from unit clarification cases in which the reach of the parties’
agreement is in dispute. See, e.g., Commonwealth Comm’ns,
Inc. v. NLRB, 312 F.3d 465, 468 (D.C. Cir. 2002). The
question here is not whether the Master Agreement reaches all
of the positions identified in the Individual Articles; rather,
the issue is whether each group identified in the Individual
Articles is a separate bargaining unit or whether all of the
positions covered by the Master Agreement constitute one
nationwide bargaining unit. Obviously, the structure of the
Master Agreement and the parties’ bargaining history may be
highly relevant to the latter inquiry.

    Sambo’s Restaurants, on which the ARD rests his
approach, surely does not make textual ambiguity a
prerequisite to examination of the parties’ bargaining history.
In that decision, the Board acknowledged the persuasive
support in the collective bargaining history for a multi-store
                               19
unit. See 212 N.L.R.B. at 788. It concluded, however, that the
support was undermined by a letter written by the union
during the course of collective bargaining negotiations with
the employer. See id. The Board never suggested that
ambiguity in the language of the collective bargaining
agreements was a prerequisite to its review of the parties’
bargaining history.

    Columbia Broadcasting Systems, 208 N.L.R.B. 825
(1974), even more explicitly rejects the ARD’s bifurcated
approach. That decision involved a master agreement that,
similar to the one at issue here, consisted of a national
agreement and local supplements. The national agreement
contained language that the Board characterized as “clearly
indicat[ing]” an “expressed intention of recognizing one
comprehensive unit.” Id. at 826 & n.10. Nonetheless, the
Board undertook a detailed examination of the parties’
collective bargaining history and put great weight on that
history in finding the existence of a single unit. See id. at 825-
26 & n.10. Moreover, the Board laid out a number of factors
which it characterized as relevant to determining whether “the
scope and nature of the local bargaining and the resulting
local supplements to the national agreement are not so
substantial as to defeat” the finding of a national bargaining
unit. See id. at 826. Those factors variously involved the
language, structure, and history of the collective bargaining
agreement. See id. And there was no suggestion that the
factors pertaining to the language of an agreement must be
examined and ambiguity found before evidence of the parties’
bargaining history or the structure of the agreement can be
considered. See id.

   Moreover, in neither National Broadcasting Co. (“NBC”),
114 N.L.R.B. 1 (1955), nor American Broadcasting Co.
(“ABC”), 114 N.L.R.B. 7 (1955), did the Board make
                              20
ambiguity in the language of the collective bargaining
agreement a prerequisite to consideration of the parties’
bargaining history. In NBC, the Board first noted the course of
the relationship between the parties prior to the execution of
the master agreement at issue. See NBC, 114 N.L.R.B. at 2. It
then detailed the language of the master agreement. See id. at
2-4. Finally, it weighed that language (which the Board
concluded supported a finding that the master agreement
covered multiple, individual bargaining units) against the
testimony describing a post-agreement course of collective
bargaining that NABET argued supported a finding of a
single unit. See id. at 2, 4-5. In identifying the appropriate
unit, the Board reviewed the language of the relevant general
and individual articles in detail and rested particularly on the
language setting forth the purpose and intent of the parties.
See id. at 4. But it also considered the evidence of bargaining
history. See id. at 4-5.

     Following a similar course of analysis, the Board in ABC
first considered the evolution of the parties’ relationship from
consent agreement to initial contract and from initial contract
to the collective bargaining agreement at issue. See ABC, 114
N.L.R.B. at 9. After describing the provisions of that “Master
Contract” in some detail, the Board turned to evidence
showing that the employer was administering the master
contract on the basis of separate units and that the parties had
bargained on the basis of separate units. See id. In view of the
entire record, the Board found that the history of bargaining
for the employees at issue had been on the basis of a separate
unit, previously certified by the Board. See id. Again, there
was no suggestion that the Board looked at the evidence of
the collective bargaining history only because the language of
the Master Contract was ambiguous.
                              21
    The Board’s wholistic approach to the record in ABC and
NBC is hardly surprising given the reliance of both decisions
on American Can Co., 109 N.L.R.B. 1284 (1954). See ABC,
114 N.L.R.B. at 9 n.2; NBC, 114 N.L.R.B. at 4 n.1. In
American Can, the Board was explicit in examining both the
language of the relevant agreements and the evidence of the
parties’ interactions as evidence of “bargaining history,” 109
N.L.R.B. at 1285, bearing on whether multiple plants covered
by the “basic” (or master) contract should be treated as one or
multiple collective bargaining units. See id. at 1285-88.
Setting the pattern for ABC and NBC, the Board considered
evidence of the past and current relationship between the
union and the company, as well as the details of both the
language and structure of past contracts and the contract at
issue. See id. Based on all of those factors, the Board found
that there was “no unequivocal manifestation of an intent” to
create a multi-plant bargaining unit. Id. at 1288.

    In light of these decisions, it seems that the ARD’s
bifurcated approach may be attributable to a misreading of
Louisiana Dock and a failure to take account of other Board
precedent. We cannot be sure what the Board meant to say,
however, because it simply adopted the Clarification Decision
without amplification. Thus, we will leave this matter for the
Board to address on remand.

    Upon finding that the Master Agreement was
“contradictory and thus ambiguous as to the existence of a
single or multiple units,” the ARD turned to the “extrinsic
evidence bearing on the single unit/multiple units question.”
Clarification Decision at 56, J.A. 603. He pointed to the fact
that only the General Articles of the Master Agreement were
signed and that the only signatories were John Clark
(President of the Union) and Day Krolik (NBC’s Senior Vice
President of Labor Relations and Talent Negotiations). See id.
                               22
at 56-57, J.A. 603-04. The ARD explained that while each
Individual Article had its own ratification process, ratification
of the entire agreement and ratification of the Individual
Articles were not independent procedures. See id. at 56, J.A.
603. He also noted that there was no indication in the record
that the Individual Articles were negotiated “separately, at a
different time, or by different representatives than those who
negotiated the Master Agreement.” Id. And he observed that
“[t]here is no indication that the Local Union representatives
on the negotiating committee are currently or have in the past
negotiated collective-bargaining agreements or even sub-
agreements such as those contained in the Master Agreement
independently in regard to the ‘unit’ of employees within their
geographic area of responsibility.” Id. at 57, J.A. 604. Finally,
citing CBS and contrasting NBC, he concluded that “the mere
existence of supplemental agreements covering specific
groupings of employees does not undercut the existence of a
single unit where the parties’ course of conduct otherwise
supports a single unit. See Columbia Broadcasting Systems,
Inc., 208 NLRB at 826; but see National Broadcasting
Company, Inc., 114 NLRB 1, 2 (1955).” Clarification
Decision at 57, J.A. 604. We find it difficult to understand
how the ARD meant to apply CBS and NBC to his factual
findings.

    The statement of law attributed to CBS is correct, as far as
it goes. But critically, the ARD fails to address the factors that
CBS describes as relevant to determining whether the nature
of bargaining and the resulting supplements to a national
agreement are so substantial as to defeat the conclusion that a
national unit has been agreed upon. See CBS, 208 N.L.R.B. at
826. Were it our place to guess, we would still be at a loss to
comprehend the ARD’s findings because the CBS factors
point in different directions. One factor cited as undermining
a potential finding that the parties’ course of conduct supports
                               23
a nationwide unit is a “reference in the master agreements to
‘units’ with inclusion of a description of each ‘plant unit.’” Id.
This favors NBC in this case. However, another factor is the
“existence of separate agreements with no master agreement.”
Id. This favors NABET in this case.

    With respect to the first factor, the references in the
NABET-NBC Master Agreement to “units” and the Scope of
Unit provisions in each Individual Article suggest that the
ARD’s conclusion that the parties’ course of conduct
supported a nationwide unit may be undermined. However,
because the NABET-NBC collective bargaining agreement is
structured as a master agreement consisting of general and
individual articles, application of the second factor supports
the conclusion that the negotiations for the Individual Articles
did not undermine the ARD’s conclusion. This may be
particularly so because it is not clear that the Individual
Articles here can be characterized as “separate agreements,”
as that term is used in CBS. They are not separately signed
and do not take effect absent ratification of the General
Articles.

    If the Board is to be true to its precedent, we believe the
CBS factors must be addressed. And given the fact that they
seem to point toward inconsistent outcomes, we think the
deference we owe the Board weighs in favor of allowing the
Board to explain whether the CBS factors are as relevant as
they appear to be and, if so, to apply the factors in the first
instance.

    We also find confusing the ARD’s attempt to distinguish
the Board’s 1955 decision in NBC. This decision is obviously
significant because the NABET-NBC collective bargaining
agreement in force in 1955 was identically structured to the
one here, and it contained a number of identical provisions.
                                24
The question in NBC was whether the Los Angeles film group
(which was the subject of an Individual Article) had, over the
course of collective bargaining, been made part of a single,
nationwide unit. See 114 N.L.R.B. at 2. As a predicate to that
assessment, the Board concluded that the other groups of
employees covered by the NABET-NBC agreement did not
constitute a single nationwide unit. See id. at 2-5.

    In an attempt to distinguish NBC, the ARD states that the
Board relied on the testimony of NABET’s attorney “that,
following the certification of [NABET] as the exclusive
representative of [the Los Angeles film service] employees,
the parties had agreed that the collective-bargaining
agreement covering them would be added to the master
agreement and that bargaining thereafter would be done in
conjunction with nationwide negotiations.” Clarification
Decision at 57 n.87, J.A. 604. The ARD notes that “[i]n this
context, the Board viewed the mere fact of nationwide
negotiations as insufficient to undercut the initial intent of the
parties that the Los Angeles ‘film service’ employees would
exist as a separate unit.” Id. The Clarification Decision
concludes that “[t]here is no comparable evidence here.” Id.

    Try as we might, we cannot discern with any certainty
how the ARD meant to distinguish NBC. We can guess that
the “comparable evidence” to which he refers is the
certification of the Los Angeles film service employees. But
we are not at all sure that this is what he intended. And if it is,
then, as earlier indicated, we wonder how the evidence of
certification that the ARD dismissed out-of-hand should be
considered. On remand, the Board must address NBC, and it
must do so in a way that makes more sense than does the
Clarification Decision.
                               25
    Based on American Can, NBC, ABC, and CBS, it appears
that when a unit clarification proceeding involves a “master
agreement” covering a number of divisions of a company, the
parties’ bargaining history and the structure of their
agreement are always relevant. If that is the case, then the
Board’s 1955 decision in NBC, while undeniably relevant, is
not likely dispositive. There has been too much bargaining
history during the decades since that decision issued to treat it
as the final word in a unit clarification proceeding focused on
the 2006-2009 Master Agreement. Just the fact that in 1955
the Board had only 14 years of collective bargaining history
to consider, see NBC, 114 N.L.R.B. at 2, whereas now it has
75 years, may be enough for the Board to conclude that the
1955 decision is not controlling.


                       III. CONCLUSION

    We deny both the petition for review and the Board’s
cross-application for enforcement and remand the case for
clarification consistent with this opinion. The Board adopted
the ARD’s Clarification Decision without explanation or
elaboration. Because we cannot discern how the Clarification
Decision applies relevant Board precedent to the facts of this
case, we are constrained to remand the case to the Board. On
remand, the Board must explain both the principles embodied
in the relevant precedent and how application of those
principles to the facts here supports its resolution of the
parties’ dispute. In addition to resolving the unit clarification
issue, the Board must also address the parties’ dispute over
the Local 11 agreement. The resolution of the Local 11 issue
may depend in part on how the Board resolves the unit
clarification issue. We leave this matter to the Board to
address in the first instance. Nothing in this decision is meant
to foreclose the Board from reopening the hearing record in
                            26
the event that it determines that additional evidence and
argument are necessary to reach an informed judgment in this
case.

                                                So ordered.
