                     Nebraska Advance Sheets
	          SERVICE EMPL. INTERNAT. v. DOUGLAS CTY. SCH. DIST.	755
	                          Cite as 286 Neb. 755

       Service Employees International Union (AFL-CIO)
          Local 226, appellant and cross-appellee, v.
             Douglas County School District 001,
                 appellee and cross-appellant.
                                    ___ N.W.2d ___

                      Filed November 1, 2013.       No. S-13-009.

 1.	 Commission of Industrial Relations: Appeal and Error. In reviewing an
      appeal from the Commission of Industrial Relations in a case involving wages
      and conditions of employment, an order or decision of the commission may be
      modified, reversed, or set aside by an appellate court on one or more of the fol-
      lowing grounds and no other: (1) if the commission acts without or in excess of
      its powers, (2) if the order was procured by fraud or is contrary to law, (3) if the
      facts found by the commission do not support the order, and (4) if the order is
      not supported by a preponderance of the competent evidence on the record con-
      sidered as a whole.
 2.	 Labor and Labor Relations. Nebraska’s Industrial Relations Act requires parties
      to negotiate only mandatory subjects of bargaining.
 3.	 ____. Mandatory subjects of bargaining include the scale of wages, hours of
      labor, or conditions of employment.
  4.	 ____. Management prerogatives, such as the right to hire, to maintain order and
      efficiency, to schedule work, and to control transfers and assignments, are not
      mandatory subjects of bargaining.
  5.	 ____. A matter which is of fundamental, basic, or essential concern to an employ-
      ee’s financial and personal concern may be considered as involving working
      conditions and is mandatorily bargainable even though there may be some minor
      influence on educational policy or management prerogative.
  6.	 ____. Vacation is a mandatory subject of bargaining.
 7.	 Commission of Industrial Relations: Labor and Labor Relations. An
      employer subject to the Industrial Relations Act may implement unilateral
      changes to mandatory subjects of bargaining only when three conditions have
      been met: (1) The parties have bargained to impasse, (2) the terms and conditions
      implemented were contained in a final offer, and (3) the implementation occurred
      before a petition regarding the year in dispute is filed with the Commission of
      Industrial Relations.
 8.	 Labor and Labor Relations: Employment Contracts: Waiver. A clear and
      unmistakable waiver of a statutory right may be found in the express language of
      a collective bargaining agreement, or it may even be implied from the structure
      of an agreement and the parties’ course of conduct.
 9.	 Labor and Labor Relations: Waiver: Proof. An employer bears the burden of
      establishing that a clear and unmistakable waiver of a statutory right in a collec-
      tive bargaining agreement has occurred.
10.	 ____: ____: ____. To establish waiver of the right to bargain by union inaction,
      the employer must first show that the union had clear notice of the employer’s
      intent to institute the change sufficiently in advance of actual implementation so
    Nebraska Advance Sheets
756	286 NEBRASKA REPORTS


     as to allow a reasonable opportunity to bargain about the change. In addition, the
     employer must show that the union failed to make a timely bargaining request
     before the change was implemented.
11.	 Labor and Labor Relations: Notice. Once a union has notice of a proposed
     change in a mandatory bargaining subject, it must make a timely request to bar-
     gain. A union cannot charge an employer with refusal to negotiate when it has
     made no attempts to bring the employer to the bargaining table.
12.	 Commission of Industrial Relations: Courts: Evidence: Appeal and Error.
     The Nebraska Supreme Court will consider the fact that the Commission of
     Industrial Relations, sitting as the trier of fact, saw and heard the witnesses and
     observed their demeanor while testifying and will give weight to the commis-
     sion’s judgment as to credibility.
13.	 Appeal and Error. An appellate court is not obligated to engage in an analysis
     that is not necessary to adjudicate the case and controversy before it.

  Appeal from the Commission of Industrial Relations.
Affirmed.
   Timothy S. Dowd, of Dowd, Howard & Corrigan, L.L.C.,
for appellant.
  David J. Kramer and D. Ashley Robinson, of Baird Holm,
L.L.P., for appellee.
  Heavican, C.J., Wright, Connolly, Stephan, McCormack,
and Cassel, JJ.
   Wright, J.
                     I. NATURE OF CASE
   Service Employees International Union (AFL-CIO) Local
226 (Local 226) appeals from the finding of the Commission of
Industrial Relations (CIR) that Douglas County School District
001 (District) did not commit a prohibited practice under the
version of the Industrial Relations Act (IRA) then in effect,
Neb. Rev. Stat. §§ 48-801 to 48-838 (Reissue 2010). Local 226
argues that the District unilaterally changed its vacation accrual
policy, declared the issue nonnegotiable, and failed to bargain
on a mandatory subject of bargaining.
   We conclude the District unilaterally changed its vacation
accrual policy but presented Local 226 with opportunities
to give input on the policy changes and request negotiations
before implementation of the changes. Local 226 failed to take
advantage of those opportunities. It negotiated and signed new
                 Nebraska Advance Sheets
	      SERVICE EMPL. INTERNAT. v. DOUGLAS CTY. SCH. DIST.	757
	                      Cite as 286 Neb. 755

collective bargaining agreements (CBA’s) for the school year
in which the new vacation accrual policy would take effect
without requesting negotiations on the new policy. In doing so,
Local 226 waived its right to negotiate on the matter of vaca-
tion accrual. We affirm the order of the CIR.

                   II. SCOPE OF REVIEW
   [1] In reviewing an appeal from the CIR in a case involving
wages and conditions of employment, an order or decision of
the CIR may be modified, reversed, or set aside by an appel-
late court on one or more of the following grounds and no
other: (1) if the CIR acts without or in excess of its powers,
(2) if the order was procured by fraud or is contrary to law,
(3) if the facts found by the CIR do not support the order,
and (4) if the order is not supported by a preponderance of
the competent evidence on the record considered as a whole.
Employees United Labor Assn. v. Douglas Cty., 284 Neb. 121,
816 N.W.2d 721 (2012).

                           III. FACTS
   Local 226 is the duly certified exclusive bargaining agent
for the District’s office personnel, educational paraprofes-
sionals, and operations division. For the 2010-11 and 2011-12
school years, Local 226 and the District entered into separate
CBA’s for each of those three bargaining units. The current
dispute over vacation accrual arose while Local 226 and the
District were negotiating the CBA’s for the 2011-12 school
year, but during the time the CBA’s for the 2010-11 school
year were still in effect.
   For the past 20 years, article 9 of the relevant CBA’s has
set forth the amount of vacation to which each employee
was entitled. But the CBA’s have never “outlined the manner
and method of accrual and distribution of the agreed upon
amount of vacation.” Rather, at all times relevant to this case,
the distribution of vacation was governed by section 4.21 of
the District’s “Policies and Regulations.” The entire policies
and regulations were incorporated by reference into article 2
of the CBA’s. Article 2 also provided that the District could
make changes to the policies and regulations at any time.
    Nebraska Advance Sheets
758	286 NEBRASKA REPORTS



The District has made changes to section 4.21 at least 10
times over the past 52 years, both with and without Local
226’s approval.
   When the District and Local 226 entered into the CBA’s for
the 2010-11 school year, section 4.21 of the policies and regu-
lations provided that employees were granted their full vaca-
tion allotment for the year in a single lump sum on August 1,
2011—the start of the school year. If an employee terminated
employment or transferred to a position in which he or she was
not eligible for vacation, any unused vacation days would be
paid out in the final paycheck. If a new employee was hired
or an employee transferred to a vacation-eligible position after
August 1, he or she would receive prorated vacation days
based on the date of hire or transfer.
   Both parties have stipulated that at their meetings on
February 9 and March 2, 2011, the District advised Local 226
that the District was “going to make” changes to section 4.21.
Under the proposed changes to section 4.21, employees would
accrue vacation throughout the school year instead of being
granted their vacation allotment in a single lump sum at the
beginning of the school year.
   On May 16, 2011, the Omaha Public Schools Board of
Education adopted the amendments to section 4.21, to be effec-
tive August 1. Local 226 did not appear at the board of educa-
tion meeting to oppose the changes.
   On May 17, 2011, the members of Local 226 were notified
of the changes adopted by the board of education. In response,
Local 226 sent a letter to the District requesting that it “cease
and desist from implementing [the vacation accrual] policy.”
Local 226 characterized the District’s action in implementing
the new policy as a “unilateral change of a mandatory subject
of bargaining[,] which is a prohibited practice.” It asked the
District to “advise as to [the District’s] intentions within the
next seven (7) calendar days.”
   In a reply letter, the District asserted that it “has the right to
change its Policies and Regulations so long as those policies
don’t violate the terms of the [ CBA’s]” and that the amend-
ments to section 4.21 were within its authority under the CBA’s
and not in violation of the provisions of the CBA’s addressing
                  Nebraska Advance Sheets
	       SERVICE EMPL. INTERNAT. v. DOUGLAS CTY. SCH. DIST.	759
	                       Cite as 286 Neb. 755

vacation. The District closed by noting, “We remain open . . .
to working with Local 226 to address any concerns about the
practical application of the revised policy.”
   Beginning in February 2011 and continuing throughout the
summer, the District and Local 226 were engaged in substan-
tive negotiations of the CBA’s for the 2011-12 school year.
During those negotiations, Local 226 did not propose any
changes to the new vacation accrual policy that was scheduled
to take effect on August 1.
   On September 13 and October 10 and 19, 2011, the District
and Local 226 signed the CBA’s for the 2011-12 school year
for the operations division, paraprofessionals, and office per-
sonnel, respectively. The CBA’s were effective retroactively to
August 1, 2011.
   In January 2012, following implementation of the new vaca-
tion accrual policy, Local 226 filed petitions with the CIR on
behalf of each of the three bargaining groups. It alleged that
the District had engaged in “a prohibited practice of bad-faith
bargaining in violation of Nebraska Revised Statute §48-824(1)
(Reissue 2004).” Local 226 asserted that the District “failed
and refused to negotiate or agree to negotiate regarding the
[v]acation [a]ccrual [p]olicy and said unilateral action on the
part of the [District] constitutes a change in the terms and con-
ditions of employment with respect to a mandatory subject of
collective bargaining.” It prayed that the CIR order the District
“to cease and desist from its continued unilateral actions”
and to maintain the previous vacation accrual policy “until or
unless [Local 226] has agreed to the same” or the CIR issued
an order altering the obligations of the parties. The District
filed answers generally denying that it had committed a pro-
hibited practice.
   The CIR held a consolidated trial on the petitions. The par-
ties adduced evidence regarding whether past practices between
the parties created an implied contractual term regarding the
manner and method of vacation accrual, whether Local 226
had an obligation to initiate negotiations after learning of the
new vacation accrual policy, and whether Local 226 consented
to the new vacation accrual policy by entering into the CBA’s
for the 2011-12 school year, among other things. Significantly,
    Nebraska Advance Sheets
760	286 NEBRASKA REPORTS



the parties presented differing accounts of the level to which
the District involved Local 226 in the development of the new
vacation accrual policy.
   The District adduced evidence that it notified Local 226
and the other unions that it was considering making changes
to section 4.21 of the policies and regulations. Dr. Germaine
Huber, chief negotiator for the board of education, testified
that she “talked with all the unions” about the new vacation
accrual policy. According to Huber, during those discussions,
the unions expressed concerns about not having vacation early
in the school year, in response to which the District incorpo-
rated into the new policy the option of applying for an advance-
ment of up to 5 vacation days. As to Local 226, Huber did not
specifically describe the District as having “negotiated” with
Local 226 over the changes to section 4.21, but maintained that
they “had discussions.”
   Local 226 presented a differing account of the events lead-
ing to adoption of the new vacation accrual policy. Suzanne
Anderson, president of Local 226, testified that at the February
9 and March 2, 2011, meetings, the District told Local 226
that the vacation accrual policy “was going to happen” and
“was going to go through.” According to Anderson, Local
226 protested the proposed changes and told the District that
it “wanted to negotiate [the new policy],” but the District
“said it was not negotiable.” Anderson conceded that the
District allowed Local 226 to provide feedback on the issue
of advance vacation days, but asserted that advancement was
the only issue about which it was given the opportunity to
provide feedback. She said that Local 226 did not make any
suggestions at the meetings other than voicing that Local 226
“wanted to negotiate [the new policy] because we did not
want that.”
   On December 6, 2012, the CIR entered an order finding
that the District had not engaged in a prohibited practice. It
first concluded that the District had “a duty to bargain over
any changes to the vacation accrual policy” because vacation
leave was a mandatory subject of bargaining under the IRA.
The CIR then turned to the question whether the District had
fulfilled its duty to bargain, noting that “the evidence as a
                 Nebraska Advance Sheets
	      SERVICE EMPL. INTERNAT. v. DOUGLAS CTY. SCH. DIST.	761
	                      Cite as 286 Neb. 755

whole does not support the notion that [the District] was not
willing to have discussions with [Local 226] about the vacation
accrual policy.” Rather, the CIR found, based on the evidence,
that the District had given Local 226 “sufficient notice” of
the proposed change such that Local 226 had an obligation
to “make a timely request to bargain.” It found the evidence
demonstrated that Local 226 failed to negotiate to impasse on
the matter. Therefore, the CIR found that Local 226 had failed
to prove that the District committed a prohibited practice under
§ 48-824(1) and dismissed all three petitions.
   Local 226 timely appeals, and the District cross-appeals.
Pursuant to our statutory authority to regulate the dockets of
the appellate courts of this state, we moved the case to our
docket. See Neb. Rev. Stat. § 24-1106(3) (Reissue 2008).
                IV. ASSIGNMENTS OF ERROR
   Local 226 generally assigns that the CIR was clearly wrong
and acted contrary to law in finding that the District did not
commit a prohibited practice by unilaterally implementing
changes to section 4.21 of the policies and regulations. More
specifically, Local 226 assigns that the CIR was clearly wrong
and acted contrary to law in finding that Local 226 had an
obligation to bargain to impasse over the District’s unilateral
change to a mandatory subject of bargaining.
   On cross-appeal, the District assigns that the CIR erred
in failing to rule that (1) the terms of the CBA’s clearly and
unambiguously granted the District the right to unilaterally
modify section 4.21, (2) the District has an established past
practice of modifying section 4.21 during the term of the
CBA’s, and (3) the District’s established practice of modifying
section 4.21 formed an implied contract term.
                         V. ANALYSIS
                    1. P rohibited P ractice
                        (a) Background
   Local 226’s appeal raises one fundamental question: whether
the District committed a prohibited practice under § 48-824(1)
by changing section 4.21, and thereby adopting a new vacation
accrual policy, without negotiating with Local 226. Section
    Nebraska Advance Sheets
762	286 NEBRASKA REPORTS



48-824(1) provided that “[i]t is a prohibited practice for any
employer, employee, employee organization, or collective-­
bargaining agent to refuse to negotiate in good faith with
respect to mandatory topics of bargaining.”
   [2-6] The IRA requires parties to negotiate only mandatory
subjects of bargaining. Scottsbluff Police Off. Assn. v. City of
Scottsbluff, 282 Neb. 676, 805 N.W.2d 320 (2011). Mandatory
subjects of bargaining include “‘the scale of wages, hours of
labor, or conditions of employment.’” Douglas Cty. Health Ctr.
Sec. Union v. Douglas Cty., 284 Neb. 109, 114, 817 N.W.2d
250, 255 (2012) (quoting § 48-818). “[M]anagement preroga-
tives, such as the right to hire, to maintain order and efficiency,
to schedule work, and to control transfers and assignments,
are not mandatory subjects of bargaining.” Scottsbluff Police
Off. Assn. v. City of Scottsbluff, 282 Neb. at 683, 805 N.W.2d
at 328. A matter which is of fundamental, basic, or essential
concern to an employee’s financial and personal concern may
be considered as involving working conditions and is manda-
torily bargainable even though there may be some minor influ-
ence on educational policy or management prerogative. Metro.
Tech. Com. Col. Ed. Assn. v. Metro. Tech. Com. Col. Area, 203
Neb. 832, 281 N.W.2d 201 (1979). Vacation is a mandatory
subject of bargaining. See, e.g., El Paso Elec. Co. v. N.L.R.B.,
681 F.3d 651 (5th Cir. 2012); Tanforan Park Food Purveyors
Council v. N. L. R. B., 656 F.2d 1358 (9th Cir. 1981); Adams
Potato Chips, Inc. v. N. L. R. B., 430 F.2d 90 (6th Cir. 1970).
See, also, FOP Lodge 41 v. County of Scotts Bluff, 13 C.I.R.
270 (2000).
   [7] Because of § 48-824(1),
      an employer subject to the IRA may implement unilat-
      eral changes to mandatory subjects of bargaining only
      when three conditions have been met: (1) The parties
      have bargained to impasse, (2) the terms and conditions
      implemented were contained in a final offer, and (3) the
      implementation occurred before a petition regarding the
      year in dispute is filed with the CIR.
Scottsbluff Police Off. Assn. v. City of Scottsbluff, 282 Neb.
at 686, 805 N.W.2d at 330. If any of these three conditions
are not met, then the employer’s unilateral implementation of
                  Nebraska Advance Sheets
	       SERVICE EMPL. INTERNAT. v. DOUGLAS CTY. SCH. DIST.	763
	                       Cite as 286 Neb. 755

changes in mandatory bargaining topics is a per se violation of
the duty to bargain in good faith. Id.
   With that background, we now turn to the facts and issues
in the instant case.

                    (b) District’s Obligation to
                     Negotiate in Good Faith
   We first note that the District acted within its authority under
the CBA’s to amend section 4.21 of the policies and regulations
and thereby adopt a new vacation accrual policy. Article 2 of
the CBA’s for the 2010-11 school year provided:
         Each and every provision of the Policies and
      Regulations incorporated by specific reference herein,
      and made a part of this Agreement, shall be binding upon
      both parties hereto, in their language as of the date hereof,
      throughout the term of this Agreement, notwithstanding
      that the School District may act to change Policies and
      Regulations after the effective date of this Agreement.
Under that language, the District had the authority to make
changes to the policies and regulations while the CBA’s for
the 2010-11 school year were in effect, but such changes,
although permissible, would not be binding upon Local 226
for the 2010-11 school year. Rather, the policies and regula-
tions in effect when the parties entered into the CBA’s would
continue to bind the parties “in their language as of the date
hereof, throughout the term of this Agreement.” Thus, under
the CBA’s with Local 226, the District had the authority to
make changes to the policies and regulations but could not
enforce those changes against Local 226 until after July 31,
2011. The District acted pursuant to that authority when it pro-
posed and adopted changes to section 4.21 of the policies and
regulations for the 2011-12 school year. Both parties agree that
the District did not implement the changes to section 4.21 until
August 1, 2011—after the CBA’s for the 2010-11 school year
had expired.
   However, despite acting within its powers under the CBA’s,
the District was still required by the IRA to negotiate regarding
the new vacation accrual policy, because it related to a manda-
tory subject of bargaining. Therefore, under § 48-824(1), the
    Nebraska Advance Sheets
764	286 NEBRASKA REPORTS



District was required to negotiate in good faith with Local 226
about the new vacation accrual policy.
   The District and Local 226 agree that no formal negotia-
tions on the new vacation accrual policy took place before the
new policy was implemented on August 1, 2011. The parties
also agree that the District was not permitted to unilaterally
implement the new policy on the ground that they had negoti-
ated to impasse, because the parties had not in fact negotiated
to impasse. Accordingly, unless Local 226 waived its right to
negotiate, the District had committed a prohibited practice and
a per se violation of its duty to bargain in good faith by imple-
menting the new vacation accrual policy without first engaging
in negotiations with the union.
                     (c) Waiver by Local 226
                      (i) Preliminary Matters
   Generally, the possibility of waiver can be considered only
after we have determined that the dispute was not covered by
the relevant collective bargaining agreement. See Douglas Cty.
Health Ctr. Sec. Union v. Douglas Cty., 284 Neb. 109, 817
N.W.2d 250 (2012). In conducting such an inquiry, we examine
whether the collective bargaining agreement “‘fully defines the
parties’ rights’” as to the topic in issue. Id. at 117, 817 N.W.2d
at 257.
   In the instant case, the rights of the parties were not defined
by the CBA’s. The implementation of the new vacation accrual
policy was effective August 1, 2011. The CBA’s expired July
31, 2012. It is true that by law, the expired CBA’s would
continue to govern the parties’ obligations to one another.
See Employees United Labor Assn. v. Douglas Cty., 284 Neb.
121, 816 N.W.2d 721 (2012). But the parties are governed by
the expired CBA’s only to the extent that the conditions of
employment previously set forth need to be maintained. See id.
Because the alleged prohibited practice would have occurred
after the CBA’s had expired, there were no agreements which
would determine the parties’ rights regarding vacation accrual.
It is thus appropriate to consider if Local 226 waived its right
to bargain regarding the accrual of vacation. See Douglas Cty.
Health Ctr. Sec. Union v. Douglas Cty., supra.
                  Nebraska Advance Sheets
	       SERVICE EMPL. INTERNAT. v. DOUGLAS CTY. SCH. DIST.	765
	                       Cite as 286 Neb. 755

                       (ii) Finding of Waiver
                            in CIR’s Order
   On appeal, Local 226 does not directly address the question
of waiver. Local 226 asserts that the CIR determined “Local
226 did not waive its right to bargain” and based its decision
that the District did not commit a prohibited practice on Local
226’s failure to bargain to impasse. See brief for appellant at
14. At the end of its order, the CIR stated that “[t]he reasons
given for [Local 226’s] failure to bargain to impasse . . . do
not constitute a convincing basis for [Local 226’s] claim that
[the District] committed a prohibited practice.” Based on
that statement, Local 226 argues that it should not have been
required to negotiate to impasse before filing petitions against
the District. That focus on the CIR’s mention of negotiating to
impasse is unfounded.
   Considering the CIR’s order in its entirety, it is clear that the
decision was based upon Local 226’s failure to request nego-
tiations. In its order, the CIR stated that the District provided
notice to Local 226 of the proposed changes to the vacation
accrual policy, at which point Local 226 became obligated to
request negotiations if it objected to the changes. Before reach-
ing the point at which bargaining to impasse was an issue for
either party, Local 226 had to request negotiations. The CIR
found that Local 226 did not.
   Once the CIR concluded that Local 226 failed to even
request negotiations, any discussion of negotiating to impasse
was extraneous to the CIR’s ultimate conclusion. Indeed, it was
only in rebutting Local 226’s allegations why it did not request
negotiations that the CIR addressed the matter of impasse.
Implicit in the CIR’s order was that Local 226 waived its right
to bargain on the issue of vacation accrual by failing to request
negotiations. As this finding was the basis of the CIR’s deci-
sion that the District did not commit a prohibited practice, it is
this finding of waiver that we review on appeal.

                    (iii) Legal Requirements
                            for Waiver
  [8,9] It is possible for employees or their representatives to
waive the right to bargain on mandatory subjects of bargaining.
    Nebraska Advance Sheets
766	286 NEBRASKA REPORTS



A clear and unmistakable waiver of a statutory right may
be found in the express language of a collective bargaining
agreement, or it may even be implied from the structure of
an agreement and the parties’ course of conduct. Hogelin v.
City of Columbus, 274 Neb. 453, 741 N.W.2d 617 (2007).
An employer bears the burden of establishing that a clear and
unmistakable waiver of a statutory right in a collective bargain-
ing agreement has occurred. Id. In the instant case, the District
had to establish that Local 226 waived its right to bargain on
the change in the vacation accrual policy.
   Although there is little Nebraska case law discussing waiver
of the right to bargain under the IRA, the federal courts
have extensively discussed waiver under the National Labor
Relations Act, 29 U.S.C. §§ 151 to 169 (2006) (NLRA). The
same standard for waiver exists under the IRA and the NLRA.
Compare Hogelin v. City of Columbus, supra, with Intern.
Broth. of Elec. Workers v. N.L.R.B., 706 F.3d 73 (2d Cir. 2013).
And “decisions under the [NLRA] are helpful in interpreting
the IRA, but are not binding.” Scottsbluff Police Off. Assn.
v. City of Scottsbluff, 282 Neb. 676, 681, 805 N.W.2d 320,
327 (2011).
   The NLRA provides that a union can waive its right to bar-
gain by failing to request bargaining or otherwise inform the
employer that the union wishes to bargain. Shortly after the
NLRA was enacted, the U.S. Supreme Court explained that
an employer cannot be held liable when the employees have
failed to act:
      Since there must be at least two parties to a bargain and
      to any negotiations for a bargain, it follows that there can
      be no breach of the statutory duty by the employer—when
      he has not refused to receive communications from his
      employees—without some indication given to him by
      them or their representatives of their desire or willingness
      to bargain. In the normal course of transactions between
      them, willingness of the employees is evidenced by their
      request, invitation, or expressed desire to bargain, com-
      municated to their employer.
         However desirable may be the exhibition by the
      employer of a tolerant and conciliatory spirit in the
                  Nebraska Advance Sheets
	       SERVICE EMPL. INTERNAT. v. DOUGLAS CTY. SCH. DIST.	767
	                       Cite as 286 Neb. 755

      settlement of labor disputes, we think it plain that the
      statute does not compel him to seek out his employees
      or request their participation in negotiations for purposes
      of collective bargaining . . . . The employer cannot,
      under the statute, be charged with refusal of that which
      is not proffered.
Labor Board v. Columbian Co., 306 U.S. 292, 297-98, 59 S.
Ct. 501, 83 L. Ed. 660 (1939).
   Since the NLRA’s enactment, many of the federal cir-
cuit courts have similarly recognized the possibility of a
waiver by employees or their representatives of the right
to bargain on mandatory subjects of bargaining. See, e.g.,
Intern. Broth. of Elec. Workers v. N.L.R.B., supra; N.L.R.B. v.
Solutia, Inc., 699 F.3d 50 (1st Cir. 2012); N.L.R.B. v. Seaport
Printing & Ad Specialties, 589 F.3d 812 (5th Cir. 2009); Regal
Cinemas, Inc. v. N.L.R.B., 317 F.3d 300 (D.C. Cir. 2003);
N.L.R.B. v. Oklahoma Fixture Co., 79 F.3d 1030 (10th Cir.
1996); N.L.R.B. v. Unbelievable, Inc., 71 F.3d 1434 (9th Cir.
1995); Intermountain Rural Elec. Ass’n v. N.L.R.B., 984 F.2d
1562 (10th Cir. 1993); N.L.R.B. v. Pinkston-Hollar Const.
Services, Inc., 954 F.2d 306 (5th Cir. 1992); N.L.R.B. v. Island
Typographers, Inc., 705 F.2d 44 (2d Cir. 1983); N. L. R. B.
v. Alva Allen Industries, Inc., 369 F.2d 310 (8th Cir. 1966);
N. L. R. B. v. Rural Electric Company, 296 F.2d 523 (10th
Cir. 1961). Under that case law, “the duty of an employer to
recognize and bargain collectively with a union as the collec-
tive bargaining representative of employees does not arise until
after the union requests the employer to bargain.” N. L. R. B.
v. Rural Electric Company, 296 F.2d at 524. The employer
must give the union notice that it intends to make changes
to the conditions of employment. See, e.g., Intern. Broth. of
Elec. Workers v. N.L.R.B., supra; N.L.R.B. v. Unbelievable,
Inc., supra; N.L.R.B. v. Island Typographers, Inc., supra. But
once notice is given, it places an obligation upon the union to
request bargaining so as not to waive the employees’ right to
bargain. See, e.g., N.L.R.B. v. Solutia, Inc., supra; N.L.R.B. v.
Seaport Printing & Ad Specialties, supra; Regal Cinemas, Inc.
v. N.L.R.B., supra; N.L.R.B. v. Oklahoma Fixture Co., supra;
N.L.R.B. v. Unbelievable, Inc., supra; Intermountain Rural
    Nebraska Advance Sheets
768	286 NEBRASKA REPORTS



Elec. Ass’n v. N.L.R.B., supra; N.L.R.B. v. Pinkston-Hollar
Const. Services, Inc., supra; N.L.R.B. v. Island Typographers,
Inc., supra; N. L. R. B. v. Alva Allen Industries, Inc., supra;
N. L. R. B. v. Rural Electric Company, supra.
   The union must act with “due diligence in requesting bar-
gaining.” N.L.R.B. v. Pinkston-Hollar Const. Services, Inc.,
954 F.2d at 310. Any less diligence amounts to a waiver by the
bargaining representative of its right to bargain. Id. “[A] union
cannot simply ignore its responsibility to initiate bargaining
over subjects of concern and thereafter accuse the employer
of violating its statutory duty to bargain.” N.L.R.B. v. Island
Typographers, Inc., 705 F.2d at 51. However, “‘[a] union is
“not required to go through the motions of requesting bargain-
ing[]” . . . if it is clear that an employer has made its decision
and will not negotiate.’” N.L.R.B. v. Solutia, Inc., 699 F.3d at
64 (alteration and ellipsis in original) (quoting Regal Cinemas,
Inc. v. N.L.R.B., supra).
   [10] Under federal case law, as under Nebraska law, the bur-
den of proving waiver rests on the employer:
         To establish waiver of the right to bargain by union
      inaction, the employer must first show that the union
      had “clear notice of the employer’s intent to institute the
      change sufficiently in advance of actual implementation
      so as to allow a reasonable opportunity to bargain about
      the change.” . . . In addition, the employer must show
      that “the union failed to make a timely bargaining request
      before the change was implemented.”
N.L.R.B. v. Unbelievable, Inc., 71 F.3d at 1440-41 (citations
omitted) (quoting American Distributing Co., Inc. v. N.L.R.B.,
715 F.2d 446 (9th Cir. 1983) (amended and superseded on
denial of rehearing)). See, also, Hogelin v. City of Columbus,
274 Neb. 453, 741 N.W.2d 617 (2007). Nonetheless, it
is important to remember that “[t]he negotiations of [an
employer] must be measured in the light of surrounding cir-
cumstances, which include corresponding attempts at good
faith negotiation by the Union.” N. L. R. B. v. Alva Allen
Industries, Inc., 369 F.2d 310, 321 (8th Cir. 1966). As the
Eighth Circuit has explained,
                  Nebraska Advance Sheets
	       SERVICE EMPL. INTERNAT. v. DOUGLAS CTY. SCH. DIST.	769
	                       Cite as 286 Neb. 755

      [a] union cannot charge an employer with refusal to nego-
      tiate when it has made no attempts to bring the employer
      to the bargaining table. . . . Nor is a union in a good
      position to charge an employer with bargaining in bad
      faith when the union itself has exhibited little, if any, real
      desire to reach a bona fide contract benefitting the mem-
      bers of the bargaining unit which it, by law, is required
      to represent.
Id. (citations omitted).

                        (iv) Application to
                          Present Appeal
   [11] In its order, the CIR concluded that Local 226 waived
its right to bargain on the subject of vacation accrual, because
Local 226 had not made a timely request to bargain. In doing
so, the CIR followed its holding in F.O.P., Lodge No. 21 v. City
of Ralston, NE, 12 C.I.R. 59, 66 (1994) (quoting N. L. R. B. v.
Alva Allen Industries, Inc., supra), in which the CIR adopted
the following proposition:
      Once a union has notice of a proposed change in a man-
      datory bargaining subject, it must make a timely request
      to bargain. “A union cannot charge an employer with
      refusal to negotiate when it has made no attempts to bring
      the employer to the bargaining table.”
As noted above, this proposition is widely enforced through-
out the federal courts. We agree with the CIR’s adoption and
continued enforcement of waiver in such a fashion.
   Applying that standard of waiver to the facts in this case,
we conclude that after receiving notice of the District’s
intended changes to the vacation accrual policy, Local 226’s
failure to make a timely request to bargain over the new
vacation accrual policy changes constituted a waiver of Local
226’s right to bargain on what would otherwise be a man-
datory subject of bargaining. By showing that Local 226
received notice of the District’s plans to implement a new
vacation accrual policy but failed to request bargaining on the
issue, the District proved a clear and unmistakable waiver by
Local 226.
    Nebraska Advance Sheets
770	286 NEBRASKA REPORTS



                     a. Notice to Local 226
   The evidence adduced before the CIR clearly showed that
the District provided sufficient notice to Local 226 that it
intended to make changes to the vacation accrual policy.
Huber testified that she notified Local 226 and the other
unions that the board of education was considering mak-
ing changes to section 4.21 of the policies and regulations.
She explained that the provision of the new policy allowing
employees to take up to 5 days advance vacation was explic-
itly added to address concerns raised by the unions when she
talked with them.
   Anderson, president of Local 226, agreed that the District
gave her “advanced information about policies and regula-
tions that [it was] considering making changes to,” including
the changes to the vacation accrual policy in 2011. She also
confirmed Huber’s testimony that the provision allowing for
the advancement of vacation days was “a result of issues and
concerns expressed by Local 226 to [the District] as [it was]
contemplating changes to the policy.” In addition to providing
advance notice that it was contemplating changes to section
4.21, the District held two meetings with Local 226 to discuss
the changes. As noted above, the parties stipulated that on
February 9 and March 2, 2011, the District met with Local 226
“to advise Local 226 of the changes [the District] was going to
make” to the vacation accrual policy.
   The evidence demonstrated that after learning of the pro-
posed changes, Local 226 had multiple opportunities to request
negotiations with the District. The District engaged Local
226 and the other unions in discussions about changes to
the vacation accrual policy prior to adopting those changes.
The District contacted the unions with advance information
about the possible changes and held meetings in February and
March 2011.
   Anderson testified that at those meetings, the policy was
presented as “nonnegotiable.” However, that testimony is con-
tradicted by Anderson’s testimony that at the meetings, Local
226 was allowed to give “feedback” that was later incorpo-
rated into the new policy. As Anderson admitted, the provision
                  Nebraska Advance Sheets
	       SERVICE EMPL. INTERNAT. v. DOUGLAS CTY. SCH. DIST.	771
	                       Cite as 286 Neb. 755

allowing for advance vacation days was added in response to
the concerns of Local 226 and other unions.
   On May 16, 2011, the board of education considered and
adopted the new vacation accrual policy at a public meeting.
Anderson testified that after the adoption of the new policy
but before it took effect on August 1, the District talked with
Local 226 about concerns it had with the policy. She stated that
the District indicated it would work with Local 226 to address
any concerns.
   On May 17, 2011, the District distributed a letter to its
employees informing them of the new vacation accrual policy
adopted on May 16. Letters were also sent to employees on
August 12 and 22 to advise them of their vacation allotment.
The District’s benefits specialist testified that all of the letters
were submitted to Local 226 for review prior to being sent.
All three letters also invited employees to contact the District’s
benefits specialist if they had any questions.
   Local 226 had numerous opportunities to express its con-
cerns about the new vacation accrual policy while negotiat-
ing with the District about the CBA’s for the 2011-12 school
year. Local 226 and the District met for negotiations no
less than 15 times between the time when Local 226 was
informed of the proposed changes and when the changes
were implemented. Because there were many negotiations
scheduled before implementation of the new vacation accrual
policy, Local 226 had multiple opportunities to raise any
concerns that it had and to add the new policy to the agenda
for negotiations.

                     b. Request to Bargain
   Local 226 did not request negotiations over the new vaca-
tion accrual policy. Rather, it consistently passed over the
opportunity to do so. At the February and March 2011 meet-
ings with the District, Local 226 did not raise any concerns
other than those relating to vacation advancement. Local 226
did not protest the new policy at the board of education meet-
ing on May 16 before it was adopted. And despite the District’s
indication that it would work with Local 226 to address its
    Nebraska Advance Sheets
772	286 NEBRASKA REPORTS



concerns, Local 226 did not raise any specific concerns or
request negotiations on the subject of vacation accrual.
   On June 10, 2011, Local 226 did send a letter to the District,
alleging that the new vacation accrual policy was a prohib-
ited practice. Local 226 requested that the District “cease and
desist from implementing [the vacation accrual] policy.” Local
226 asked the District to “advise as to [the District’s] inten-
tions.” When the District responded on June 17, it stated, “We
remain open . . . to working with Local 226 to address any
concerns about the practical application of the revised policy.”
Local 226 did not respond. Rather, Local 226 used its letter of
June 10 as an excuse not to negotiate, because it had already
expressed its objections.
   Despite alleging on June 10, 2011, that the District had com-
mitted a prohibited practice, Local 226 did not file petitions
with the CIR based on that prohibited practice until 7 months
later, on January 27 and 30, 2012. It entered into negotiations
with the District and ultimately signed new CBA’s for the 2011-
12 school year well before filing this action. In the face of a full
negotiation schedule and the prospect of adopting the CBA’s
that would make the new policy binding on its members, Local
226 still did not raise the matter of vacation accrual. Indeed,
Huber testified that Local 226 did not make any substantive
proposals regarding vacation accrual during negotiations of
the CBA’s for the 2011-12 school year. Anderson admitted that
Local 226 “did not bring it to the table.”
   At the conclusion of these scheduled negotiations, Local
226 did in fact enter into new CBA’s with the District. These
CBA’s explicitly incorporated the entire policies and regula-
tions, including the new vacation accrual policy. Thus, upon
entering into these new CBA’s, the vacation accrual policy to
which Local 226 objected was made binding upon Local 226
and its members.
   Local 226 argues that it did request negotiations with the
District and maintains that the District presented the vaca-
tion accrual policy as nonnegotiable. The CIR considered and
rejected those claims. After mentioning Anderson’s testimony
that Local 226 requested negotiations about the new vaca-
tion accrual policy, the CIR found that the District did not
                  Nebraska Advance Sheets
	       SERVICE EMPL. INTERNAT. v. DOUGLAS CTY. SCH. DIST.	773
	                       Cite as 286 Neb. 755

commit a prohibited practice precisely because Local 226
failed to request negotiations. In so finding, the CIR explicitly
rejected Local 226’s contention that it requested negotiations
and implicitly rejected the testimony upon which the claim
was based. Furthermore, the CIR rejected much of Anderson’s
testimony attempting to explain why Local 226 did not nego-
tiate. Significantly, the CIR found that Anderson’s testimony
that the District considered the vacation accrual policy non-
negotiable was not supported by the other evidence in the
case. Taken as a whole, the CIR’s order concluded that the
evidence supported the District’s version of the facts over that
of Local 226.
   [12] This court will consider the fact that the CIR, sitting as
the trier of fact, saw and heard the witnesses and observed their
demeanor while testifying and will give weight to the CIR’s
judgment as to credibility. Crete Ed. Assn. v. Saline Cty. Sch.
Dist. No. 76-0002, 265 Neb. 8, 654 N.W.2d 166 (2002). As an
appellate court, we do not reweigh testimony. See Henderson v.
City of Columbus, 285 Neb. 482, 827 N.W.2d 486 (2013). The
testimony before the CIR presented two versions of the facts
surrounding the new vacation accrual policy. Per our scope of
review, we give weight to the CIR’s acceptance of one version
of the facts over the other.

                  c. Conclusion as to Waiver
   We conclude Local 226 was put on notice of the proposed
changes and consequently became obligated to request bar-
gaining if it had any concerns about the new policy. Local
226 was given more than sufficient opportunity to express
concerns about the new vacation accrual policy and negoti-
ate regarding it. Those opportunities were available before
the policy went into effect and before it became binding upon
Local 226.
   Considering the evidence as a whole and giving deference
to the CIR’s weighing of the evidence, we conclude that Local
226 did not request to bargain. Instead, the preponderance of
the competent evidence before the CIR clearly demonstrated
that Local 226 sat on the knowledge that the District planned
to make changes to the vacation accrual policy and signed
    Nebraska Advance Sheets
774	286 NEBRASKA REPORTS



new CBA’s that made those changes binding on Local 226’s
members. Such evidence established a clear and unmistakable
waiver of Local 226’s right to negotiate.
   By showing that Local 226 failed to request bargaining after
being placed on notice of the proposed changes, the District
proved clear and unmistakable waiver by Local 226 of the right
to negotiate. Because Local 226 waived such right, the District
did not commit a prohibited practice by failing to negotiate
with Local 226 about the new vacation accrual policy. The CIR
did not err in so finding.
                        2. Cross-Appeal
   In the event that we did not affirm the CIR’s finding that
Local 226 failed to bargain, thereby precluding a ruling that
the District committed a prohibited practice, the District’s
cross-appeal provided three alternate routes by which the CIR
could have reached the same result. The District argues that
the CIR erred in not finding against Local 226 for one of those
three reasons and asks that we affirm the ultimate decision of
the CIR.
   [13] Having affirmed the CIR’s decision, we do not reach
the District’s errors on cross-appeal. An appellate court is
not obligated to engage in an analysis that is not necessary to
adjudicate the case and controversy before it. Holdsworth v.
Greenwood Farmers Co-op, ante p. 49, 835 N.W.2d 30 (2013).
                      VI. CONCLUSION
   For the aforementioned reasons, we affirm the CIR’s order
finding that the District did not commit a prohibited practice
and dismissing Local 226’s petitions.
                                                   Affirmed.
   Miller-Lerman, J., not participating.
