In this labor relations case, the Washington County Police Officers Association (the Association) filed two unfair labor practice complaints against Washington County (County) for unilaterally adopting a Complaint Investigations Procedures Manual that allegedly infringed on employees’ rights to union representation during investigatory interviews.1 We are asked to decide whether the Employment Relations Board (ERB) correctly dismissed those complaints, without a hearing, for failure to allege an “issue of fact or law.” ORS 243.676(l)(b). The Court of Appeals held that ERB correctly dismissed one complaint, but incorrectly dismissed the other; it remanded the latter complaint to ERB for further proceedings. Washington Cty. Police Officers v. Washington Cty., 127 Or App 545, 550, 873 P2d 432 (1994). We allowed review to determine whether an amendment to the County’s Complaint Investigations Procedures Manual, adopted in response to an order of ERB, was subject to immediate collective bargaining, before implementation of the amendment, by the statutes requiring collective bargaining “with respect to employment relations.” ORS 243.672(l)(e), 243.650(4), 243.650(7).2 For the reasons set *433out below, we hold that it was not. The decision of the Court of Appeals is affirmed in part and reversed in part. The order of the Employment Relations Board is affirmed.
The proceedings before this court stem from a lengthy history of litigation between the parties, involving three decisions of ERB and two separate unfair labor practice complaints filed by the Association. The battle began in February 1990, when the Association filed a complaint with ERB alleging that the policies and practices of the County with respect to the participation of Association representatives in investigatory interviews conducted by the County constituted unfair labor practices in violation of ORS 243.672(l)(a). The Association prevailed in that ERB proceeding. The County was ordered to cease and desist and to modify its written policy “consistent” with ERB’s opinion and order.3 Washington County Police Officers Association v. Washington County, 12 PECBR 693, 706-07 (1991) (WCPOA I).
The Association, concerned that ERB had misstated Oregon law with respect to an employee’s right to consult with Association representatives during investigatory interviews, petitioned ERB for reconsideration of its opinion.4 *434ERB granted that petition and held that Oregon law does not provide an employee the right to consult with a union representative during an investigatory interview. Washington County Police Officers Association v. Washington County, 12 PECBR 693, on reconsideration, 12 PECBR 727, 729 (1991) (WCPOA II). No petition for judicial review was filed with respect to either WCPOA I or II, and we do not address the correctness of either. The dispute before this court, although connected to WCPOA I and II, is a separate matter. We turn now to that dispute.
Immediately after ERB decided WCPOA II, the County chose to implement the directive from ERB in WCPOA II by promulgating an amended Complaint Investigations Procedures Manual. The new manual adopted, almost verbatim, the minimum representation rights required by ORS 243.672(l)(a), as decided and enumerated by ERB in its unappealed decisions, WCPOA I and II.
On March 20,1992, the Association filed a complaint alleging two unfair labor practices by the County: one aimed at the content of the manual and the other aimed at the procedure by which the manual had been adopted. The first allegation was that the amended policy violated ORS 243.672(l)(a) by not affording to employees a right to consult with a labor representative during investigatory interviews. The second allegation was that, because the procedures used for the investigation of disciplinary complaints were subject to mandatory collective bargaining, the County had violated ORS 243.672(l)(e) when it promulgated the amended policy “unilaterally.”
ERB dismissed the entire complaint for failure to state issues of fact or law. Washington County Police Officers’ Association v. Washington County, 13 PECBR 627 (1992) (WCPOA III). ERB dismissed the first theory, relating to the content of the manual, on the ground that the Association was alleging a violation of a right that ERB had held to be nonexistent in WCPOA I and II and, because those two decisions had not been appealed, no issue of fact or law existed. ERB dismissed the second theory, viz., that collective bargaining was required before an amendment to the manual could be adopted, because the County had done nothing, in ERB’s opinion, but comply with ERB’s earlier affirmative order for *435relief. ERB did not reach the question whether, absent claim preclusion, employee rights to union representation in investigatory interviews were otherwise subject to mandatory bargaining. WCPOA III, 13 PECBR at 634 n 1.
On judicial review, the Court of Appeals affirmed ERB’s dismissal of the first theory in the Association’s complaint, but reversed the dismissal of the second theory. It then remanded the case to ERB for a determination whether the policy reflected in the manual was subject to mandatory bargaining. For the reasons that follow, we affirm the decision of the Court of Appeals with respect to the first theory, but reverse as to the second.
ISSUE PRECLUSION
The Court of Appeals held that the Association’s first theory was barred by the common law doctrine of issue preclusion. Washington Cty. Police Officers, 127 Or App at 547. We agree. This court has held:
“If one tribunal has decided an issue, the decision on that issue may preclude relitigation of the issue in another proceeding if five requirements are met:
“ 1. The issue in the two proceedings is identical. North Clackamas School Dist. v. White, [305 Or 48, 53, 750 P2d 485, modified on other grounds 305 Or 468, 752 P2d 1210 (1988)]; State Farm Fire & Cas. v. Reuter, [299 Or 155, 158, 700 P2d 236 (1985)].
‘ ‘2. The issue was actually litigated and was essential to a final decision on the merits in the prior proceeding. Heller v. Ebb Auto Co., 308 Or 1, 5, 774 P2d 1089 (1989).
“3. The party sought to be precluded has had a full and fair opportunity to be heard on that issue. Chavez v. Boise Cascade Corporation, 307 Or 632, 635, 772 P2d 409 (1989); State v. Ratliff, [304 Or 354, 258, 744 P2d 247 (1987)].
“4. The party sought to be precluded was a party or was in privity with a party to the prior proceeding. North Clackamas School Dist. v. White, supra, 305 Or at 53; State Farm Fire & Cas. v. Reuter, supra, 299 Or at 159.
“5. The prior proceeding was the type of proceeding to which this court will give preclusive effect. North Clackamas School Dist. v. White, supra, 305 Or at 52; State v. Ratliff, supra, 304 Or at 258.”
*436Nelson v. Emerald People’s Utility Dist., 318 Or 99, 104, 862 P2d 1293 (1993) (footnote omitted). In the present case, there is no dispute concerning the first and fourth elements of issue preclusion, viz., identity of issue and identity of party. The legal validity of the Court of Appeals’ determination depends on whether the second (actually litigated and essential to final decision), third (full and fair opportunity to be heard), and fifth (prior proceeding of type that will be given preclusive effect) elements of issue preclusion in Nelson were satisfied.
The second element of issue preclusion, requiring that the issue actually was litigated and essential to a final decision on the merits in the prior proceeding, was satisfied by ERB’s decisions in WCPOA I and 71. ERB’s interpretation of the rights provided by ORS 243.672(l)(a) was essential to its final decisions on the merits in those proceedings. The issue in WCPOA I was whether the County had violated an employee’s rights under ORS 243.672(l)(a). The extent of those rights was central to that dispute. The Association now argues that the enumeration of rights in WCPOA I was “dictum” and, because it was “dictum,” the Association was not required either to accept that enumeration or to seek judicial review of it. We do not agree with the Association’s characterization of the rights enumerated in WCPOA I. Moreover, in WCPOA II, the primary question before ERB was the extent of an employee’s right to consult with a labor representative during an investigatory interview. The Association specifically argued that issue and requested a ruling. Thus, the Association’s argument that the issue of an employee’s rights to representation by the Association in an investigatory interview was not litigated, or not essential to ERB’s decision, is not well taken.
The third element of issue preclusion, requiring that the party sought to be precluded had a full and fair opportunity to be heard on the issue to be precluded, was satisfied when ERB reconsidered WCPOA I. In their petition, the Association urged
“that the Board reconsider its decision with respect to the role of a labor representative during a[n investigatory] hearing. In particular, the Association believes it is appropriate for a labor representative to ‘counsel’ an employee during a[n investigatory] interview.”
*437See WCPOA II, 12 PECBR at 727 (quoting petition). The petition for reconsideration, along with the legal points and authorities contained therein, which were considered and dealt with on the merits in a reconsideration hearing, constituted a full and fair opportunity to present arguments on that legal issue. The Association’s argument to the contrary is not well taken.
The fifth element of issue preclusion, requiring that the prior proceeding be “the type of proceeding to which this court will give preclusive effect,” also was satisfied. This court discussed the preclusive effect that an agency proceeding could have on further proceedings of the same agency in North Clackamas School Dist., 305 Or at 52. After quoting several commentaries, this court concluded:
“We see no reason why the rules of res judicata should not apply in this case. The same quality of proceedings and opportunity to litigate is present in both proceedings. If the incentive to litigate the question is substantially the same, the procedural requisites for application of the issue preclusion rule would appear to exist. See Restatement (Second) of Judgments, Introductory Note to Ch 6 at 265 (1980).”
Id. at 52.
This case is no different. The parties had a demonstrated incentive to litigate the representational rights afforded by ORS 243.672(l)(a) in WCPOA I and II. This is demonstrated particularly by the Association’s petition for reconsideration of ERB’s limitation on the “right to consultation.” Failure to seek judicial review of the resulting decision of ERB as to those representational rights made them final as between these parties and precludes the Association from raising the same issue here.
We hold that ERB and the Court of Appeals correctly determined that the Association’s first theory in its unfair labor practice complaint, relating to the contents of the revised manual, presented no issue of fact or law. We now review ERB’s dismissal of the Association’s second theory.
*438BARGAINING AFTER AN ERB ORDER
As noted, the Association argued that the contents of the manual were a mandatory subject of collective bargaining. From that premise, the Association reasoned that, whatever the county’s reasons for changing the manual might be, it could not make those changes without first bargaining collectively with the Association. ERB’s decision to dismiss that theory did not rely on any specific “exception” to collective bargaining delineated in the collective bargaining statutes. Neither did it rely on past decisions of this court on the subject of mandatory collective bargaining. ERB instead appears to have rested its decision on two separate legal contentions not previously considered by this court.
First, ERB appeared to assert that an employer has no duty to bargain whenever changes in employment practices are made in order to bring the employer into compliance with the minimum requirements of law. It held:
“An employer has no obligation to bargain over changes made to meet minimum legal requirements. * * * If an employer were notified, or itself determined that it had violated minimum wage requirements, an employer would have to raise wages to the minimum wage and would not be obligated to bargain.”
WCPOA III, 13 PECBR at 633-34 (footnote omitted).
The Court of Appeals criticized and reversed ERB’s dismissal on that basis. As stated by the Court of Appeals:
“To use ERB’s example, an employer that wishes to cure its violation of the minimum wage law must comply with the minimum wage law and any bargaining duty imposed by ORS 243.672(l)(e). The minimum wage law does not require an employer to make unilateral policy changes in wages in order to attain compliance. In ERB’s hypothetical, the employer’s conundrum is the result of its potential violation of both the minimum wage law and the bargaining law, and it cannot excuse its violation of one law by pointing to a perceived ‘need’ to violate the other. Employer’s difficulties in achieving timely compliance with all applicable laws in this context may justify some adjustment of remedy by ERB, but they do not excuse employer from liability for violating its legal duties.”
*439Washington Cty. Police Officers, 127 Or App at 548 n 1 (emphasis supplied). We agree with the Court of Appeals that ERB’s first basis for dismissal is not sufficient. The fact that two legal duties may collide, or appear in conflict, does not excuse an employer from making good faith efforts to comply with those duties, or excuse ERB from enforcing them. We agree with the Court of Appeals, therefore, that dismissal on that ground alone would have been reversible error — but ERB did not rely solely on that ground.
ERB also relied on its authority to order affirmative relief necessary to effectuate the purposes of the public employees’ collective bargaining law (PECBA).5 ERB asserted that an obligation to bargain over the implementation of an ERB order would delay compliance with the law and defeat the immediate affirmative relief required for an unfair labor practice. It held:
“To the extent that the Association contends that the County violated ORS 243.672(l)(e) by unilaterally changing conditions of employment when revising the manual, we reject that contention. When revising the manual, the County did nothing more than comply with the minimum legal requirements regarding employee rights to union representation in investigatory interviews, as set forth in [Washington County Police Officers Association v. Washington County, 12 PECBR 693, on reconsideration, 12 PECBR 727 (1991)]. In that case, we held that a prior edition of the manual infringed on employee rights and violated subsection (l)(e) and ordered the County to modify its manual.
“* * * If we were to adopt the Association’s argument, we would have to hold that an employer’s modification of an unlawful practice would not be permitted, unless agreement were reached or the PECBA dispute resolution process was completed. Such a holding would require an employer to *440continue its unlawful conduct while bargaining was completed. We will not require employers to engage in unlawful conduct.”
WCPOA III, 13 PECBR at 633.
We agree with ERB’s contention that to require collective bargaining, after an ERB order, about a specific directive in that order, would be inconsistent with ERB’s authority — indeed duty — to order immediate affirmative relief. ORS 243.676(2)(c) requires ERB, on the finding of an unfair labor practice, to order that the person cease and desist from the unfair labor practice and order “such affirmative action * * * as necessary to effectuate the purposes of [ORS 243.650 to 243.782].” To permit a delay in the implementation of a specific affirmative order for immediate relief would thwart the affirmative relief required by ORS 243.676(2)(c).
An ERB order giving an employer broad discretion over the time or method of compliance with that order does not necessarily extinguish any pre-existing duty to bargain over decisions affecting employee relations.6 But an order requiring a specific act, or requiring immediate compliance, cannot, if it is to be effective, be subjected to an indeterminate delay by a party’s insistence that it be bargained over before implementation.7 We are left, then, with a question of interpretation, viz., whether the ERB order, requiring the County to amend its policy manual “within 14 days of this Order [and] consistent with this Order,” left the time or method of compliance up to the employer. As set forth below, we hold that it did not.
Three circumstances are dispositive in this inquiry. First, the Association, in its original unfair labor practice complaint against the County, sought specific affirmative *441relief in the form of an ERB order ‘ ‘ [r] equiring that Washington County amend its Complaint Investigation Procedures Manual to Comply with State law concerning rights of Association members to Association representation during investigatory interviews.” WCPOA I, UP-15-90 (Complaint, February 2, 1990). Second, ERB specifically ordered the County to “modify its Manual within 14 days” of the ERB order, to be “consistent with [that] Order.” The order is specific, both as to time and method of compliance. The main body of the ERB opinion and order succinctly sets out the state law concerning the rights requested, and the order required the modification to be complete within 14 days of the ERB order. Any reasonable person, having read the unfair labor practice complaint, the opinion, and the affirmative order, would understand the order to direct the County to amend its manual to meet minimum state law requirements and would know specifically what, in the view of ERB, those minimum requirements were.
Finally, and even if there were some room for debate over the scope of ERB’s order in WCPOA I, the ERB ordér in WCPOA III definitively interpreted the order in question as an order to adopt affirmatively the state law requirements outlined in WCPOA I and II into the County’s manual. ERB held:
“In short, [the] manual provisions that the Association challenges are consistent with the directives that this Board has issued in [Washington County Police Officers Association v. Washington County, 12 PECBR 693, on reconsideration, 12 PECBR 727 (1991)]. Because nothing in the County’s manual contravenes our prior Orders, the complaint fails to raise a question of law.
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“ * * * When revising the manual, the County did nothing more than comply with the minimum legal requirements regarding employee rights to union representation in investigatory interviews, as set forth in [Washington County Police Officers Association v. Washington County, 12 PECBR 693, on reconsideration, 12 PECBR 727 (1991)]. In that case, we held that a prior edition of the manual infringed on employee rights and violated subsection (l)(a) and ordered the County to modify its manual.”
WCPOA III, 13 PECBR at 633.
*442We hold that ERB’s order in WCPOA I directed the County to provide immediate affirmative relief of a specific nature. To require bargaining before implementation of that order would have been inconsistent with that order and, as such, error. The Court of Appeals erred in reaching a contrary result.
CONCLUSION
For the forgoing reasons, we hold that the Association’s first theory in its unfair labor practice complaint was barred by the common law doctrine of issue preclusion. The second theory, seeking mandatory bargaining over the content of the County’s Complaint Investigations Procedures Manual in advance of making any changes in it, was precluded by ERB’s order.
The decision of the Court of Appeals is affirmed in part and reversed in part. The order of the Employment Relations Board is affirmed.
ORS 243.672(1) provides in part:
“It is an unfair labor practice for a public employer * * * to do any of the following:
“(a) Interfere with, restrain or coerce employees in or because of the exercise of rights guaranteed in ORS 243.662.
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“(e) Refuse to bargain collectively in good faith with the exclusive representative.”
ORS 243.662 provides:
“Public employees have the right to form, join and participate in the activities of labor organizations of their own choosing for the purpose of representation and collective bargaining with their public employer on matters concerning employment relations.”
ORS 243.650 provides in part:
“(4) ‘Collective bargaining’ means the performance of the mutual obligation of a public employer and the representative of its employees to meet at reasonable times and confer in good faith with respect to employment relations, or the negotiation of an agreement, or any question arising thereunder, and the execution of a written contract incorporating any agreement reached if requested by either party. However, this obligation does not compel either party to agree to a proposal or require the making of a concession.
*433“(7) ‘Employment relations’ includes, but is not limited to, matters concerning direct or indirect monetary benefits, hours, vacations, sick leave, grievance procedures and other conditions of employment.”
After a lengthy opinion setting forth its views with respect to the minimum rights to representation in investigatory interviews afforded by Oregon law, ERB issued the following order:
“1. The County shall cease and desist from instructing Association representatives to be silent during investigatory interviews of Association members and [from] limiting the role of the Association representative to that of an observer during such interviews.
“2. The County shall cease and desist from interfering with employees’ representational rights in the Manual by relegating the employee representative to the role of an observer during any interview or meeting to which the employee’s right to representation attaches. The County shall modify its Manual within 14 days of this Order consistent with this Order.”
Washington County Police Officers Association v. Washington County, 12 PECBR 693, 706-07 (1991).
We emphasize that this case is a dispute between an employer and a collective bargaining representative. No individual employee is a party to the case, and no employee’s individual rights are in issue.
ORS 243.676(2) provides in part:
“Where, as a result of the hearing required pursuant to subsection (l)(c) of this section, the board finds that any person named in the complaint has engaged in or is engaging in any unfair labor practice charged in the complaint, the board shall:
(<* * * * *
“(c) Take such affirmative action, includingbut not limited to the reinstatement of employees with or without back pay, as necessary to effectuate the purposes of ORS * * * 243.650 to 243.782 * *
ERB itself made this point in WCPOA III, 13 PECBR at 634 n 1:
“Of course, an employer that implements a change that does more than the law requires would be obligated to bargain over the change. But that situation is not present here.”
Of course, our ruling in this regard does not prevent either side from seeking to bargain over any appropriate subject of bargaining at any time. We hold only that bargaining may not delay implementation of certain specific orders of ERB, such as the one at issue here. We also recognize that specific affirmative relief by order of ERB is not always necessary, or appropriate, to effectuate the purposes of ORS 243.650 to 243.782.