In this case, the issue is whether the *172Michigan Employment Relations Commission used the appropriate standard in determining that the City of Southfield, a public employer, had not committed an unfair labor practice under the Michigan public employment relations act.1 The charge was filed against the city after it unilaterally transferred certain job duties, previously performed interchangeably by several bargaining units, to one of these groups. Because the transferred work had not been performed exclusively by the bargaining unit represented by the objecting labor organization, the merc found no violation of the duty to bargain. We conclude, for reasons set forth below, that the merc did not err, and we reverse the decision of the Court of Appeals.
i
In connection with its law enforcement activities, the City of Southfield operates an auto pound which, in the past, had been staffed interchangeably by police officers, command officers, and civilian employees. The city also has a crime prevention program which had been staffed by both police officers and civilian safety technicians. When the city found it necessary, because of concerns about crime, to put more police on the street, the police officers in those two sections were reassigned to street duty, and their jobs in crime prevention and the auto pound were assumed by the civilian employees.
Thereafter, the Southfield Police Officers Association, a labor organization representing police officers and police officer specialists employed by the city, filed an unfair labor practice charge with the merc. The association complained that the city had violated the pera by refusing to bargain con*173cerning its decision to transfer bargaining unit work in crime prevention and the auto pound to civilian employees who are members of a different bargaining unit and are represented by a different union.
Following a hearing, the hearing referee issued a decision in which he recommended dismissal of the unfair labor practice charge because the association had not established that the work transferred had been exclusively performed in the past by the association’s members. The hearing referee based his decision on reasoning set forth in an unpublished opinion of the Court of Appeals, Detroit Police Lieutenants & Sergeants Ass’n v Detroit, decided February 22, 1982 (Docket No. 52931). Thereafter, the hearing referee’s decision was affirmed by the merc, which explained:
Charging Party argues that the Commission is not bound to follow an unpublished Court of Appeals decision, and that the [hearing referee] erred in requiring Charging Party to show that the auto pound work and crime prevention work was performed exclusively by its members. We agree with Charging Party that an unpublished opinion of the Court of Appeals is not binding beyond that case. However, since the Detroit Lieutenants and Sergeants, we have applied the "exclusivity” rule to cases where unilateral transfer of bargaining unit work has been alleged because the rationale of the Court in that case was sound. Where particular job functions have been assigned interchangeably to both represented and nonrepresented employees, or to members of different units, and the unions involved have had an opportunity to demand bargaining over these assignments in the past, the mere fact that an employer assigns more of the work to one of these groups should not give rise to a bargaining obligation. See City of East Detroit [v Police Officers Ass’n], 1982 MERC Lab Op 1442, *1741450; City of Dearborn [v Alcamo], 1984 MERC Lab Op 78, 81.
On appeal, the association challenged the "exclusivity rule” followed by the merc. The Court of Appeals concluded that in the absence of "any published opinions rendered by this Court or by our Supreme Court construing pera that would govern the association’s contention,” the exclusivity rule had "no basis in law.” Southfield Police Officers Ass’n v Southfield, 162 Mich App 729, 732-733; 413 NW2d 489 (1987). Refusing to apply the "exclusivity rule,” the Court of Appeals panel then substituted the so-called "adverse impact” rule formulated by the National Labor Relations Board and set forth in Westinghouse Electric Corp, 150 NLRB 1574, 1577; 58 LRRM 1257 (1965), and AMCAR Div, ACF Industries, Inc v NLRB, 596 F2d 1344, 1349 (CA 8, 1979). In its opinion, the Court of Appeals stated:
The dispositive question is not whether the work was performed exclusively by union employees in the past, but rather whether the employer’s proposed reassignment would be inconsistent with previously established operating practices, would effect a change in conditions of employment, or result in a significant impairment of job tenure, employment security or reasonably anticipated work opportunities for those in the bargaining unit. This standard is certainly more favorable to the interests of the employees than that applied by merc in the instant case. Given our Court’s avowed adherence to the principle that pera should be construed more liberally than the National Labor Relations Act, it would be anomalous for us to uphold merc’s exclusivity rule. We conclude that a proper disposition of this case requires remand for further conclusions of law and, if necessary, further findings of fact consistent with the test applied in AMCAR. [Id. at 734.]
*175This Court then granted the city’s application for leave to appeal. 430 Mich 859 (1988).
ii
Findings by the merc with respect to questions of fact are conclusive if supported by competent, material, and substantial evidence on the record considered as a whole. Const 1963, art 6, § 28, MCL 423.216(e); MSA 17.455(16)(e). However, as we recognized in U of M Regents v Employment Relations Comm, 389 Mich 96, 102; 204 NW2d 218 (1973), this Court may review the law regardless of the factual findings of the commission. The Administrative Procedures Act, 1969 PA 306, MCL 24.201 et seq.; MSA 3.560(101) et seq. provides in pertinent part:
Except when a statute or the constitution provides for a different scope of review, the court shall hold unlawful and set aside a decision or order of an agency if substantial rights of the petitioner have been prejudiced because the decision or order is any of the following:
(a) In violation of the constitution or a statute. [MCL 24.306(l)(a); MSA 3.560(206)(l)(a).]
Judicial review includes the determination of whether a decision of the merc is "authorized by law,” Const 1963, art 6, § 28, and such a decision may be set aside on appeal if based on a "substantial and material error of law.” MCL 24.306(l)(f); MSA 3.560(206X1X0.
In the instant case, the Court of Appeals determined that the merc’s use of the exclusivity rule was, in effect, an "error of law.” We disagree.
Although this Court has observed that an unpublished opinion of the Court of Appeals is of no precedential value, see Stine v Continental Casu*176alty Co, 419 Mich 89, 95, n 2; 349 NW2d 127 (1984), it does not necessarily follow that the absence of published precedent as reinforcement for a long-established merc rule deprives that rule of any relevance. In AFSCME v Wayne Co, 152 Mich App 87, 98; 393 NW2d 889 (1986), lv den 426 Mich 875 (1986), the Court of Appeals recognized that
[i]t is impossible to promulgate specific administrative rules in anticipation of every conceivable situation prior to the enforcement of a statute. Thompson v Dep’t of Corrections, 143 Mich App 29, 32-33; 371 NW2d 472 (1985), conflicts order den 422 Mich 1238 (1985). An administrative agency may thus announce new principles of law through adjudicative proceedings in addition to doing so through its rule-making powers. DAIIE v Comm’r of Ins, 119 Mich App 113, 117; 326 NW2d 444 (1982), lv den 417 Mich 1077 (1983). The effective administration of a statute by an administrative agency cannot always be accomplished through application of predetermined general rules. Rather, some principles of interpretation must evolve in response to actual cases in controversy presented to the agency. An administrative agency must therefore have the authority to act either by general rule or by individual order.
For over ten years, the merc has applied the exclusivity rule as a screening device in identifying those situations in which a duty to bargain may or may not arise out of the transfer of bargaining unit work. We cannot conveniently dismiss this longstanding interpretation of the pera by the merc as an "error of law” merely because no appellate court in this jurisdiction thus far has spoken publicly on the issue. This Court has traditionally accorded deference to the agency interpretation of a statute:
*177It is well settled that the construction placed upon statutory provisions by any particular department of government for a long period of time, although not binding upon the courts, should be given considerable weight. [Allen v Detroit Police Dep’t Trial Bd, 309 Mich 382, 386; 15 NW2d 676 (1944). See also Breuhan v Plymouth-Canton Community Schools, 425 Mich 278, 282-283; 389 NW2d 85 (1986).]
Thus, we shall independently review the exclusivity rule on its merits and in light of its history to determine whether the merc erred in its application of the rule to the circumstances of this case.
hi
Under § 9 of the pera, MCL 423.209; MSA 17.455(9), public employees enjoy the right to organize and engage in collective bargaining. Section 15 of the pera2 requires a public employer to bargain collectively with the recognized representatives of its public employees. Certain issues including "wages, hours and other terms and conditions of employment” are considered to be mandatory subjects of collective bargaining. MCL 423.215; MSA 17.455(15); Detroit Police Officers *178Ass’n v Detroit, 391 Mich 44, 54-55; 214 NW2d 803 (1974); Local 1277, Metropolitan Council No 23, AFSCME v Center Line, 414 Mich 642, 652; 327 NW2d 822 (1982). Issues falling outside of this category are classified as either permissive or illegal subjects of bargaining. Id. at 652. The classification of a particular issue as a mandatory or permissive subject "plays a vital role in the bargaining dynamics of the public sector.” Id. at 653. Unilateral action on the part of a public employer, or its refusal to engage in collective bargaining with respect to a mandatory subject, may constitute an unfair labor practice under § 10(1)(e) of the PERA. MCL 423.210(1)(e); MSA 17.455(10)(1)(e).
The determination of what constitutes a mandatory subject of bargaining under the pera is to be decided case by case. Local 1277, supra, p 659; Bay City Ed Ass’n v Bay City Public Schools, 430 Mich 370, 376; 422 NW2d 504 (1988); Detroit Police Officers Ass’n v Detroit, 61 Mich App 487, 490-491; 233 NW2d 49 (1975), lv den 395 Mich 756 (1975).
The Michigan courts have held, in varying contexts, that the duty to bargain extends to a public employer’s diversion of unit work to nonunit employees or to the subcontracting of the unit work to independent contractors. See, e.g., Detroit Police Officers Ass’n v Detroit, 428 Mich 79; 404 NW2d 595 (1987) (the city violated its duty to bargain over its decision to subcontract court security work); Plymouth Fire Fighters Ass’n, Local 1811 v Plymouth, 156 Mich App 220; 401 NW2d 281 (1986) (the city committed an unfair labor practice in subcontracting work which had been performed by union members); Lansing Fire Fighters Union, Local 421 v Lansing, 133 Mich App 56; 349 NW2d 253 (1984) (the city violated its duty to bargain about its decision to remove work done by unit members and hire nonmembers to perform the *179work); Van Buren Public School Dist v Wayne Circuit Judge, 61 Mich App 6; 232 NW2d 278 (1975) (the school district’s decision to replace its bus drivers with a private transportation firm is a mandatory subject of bargaining); cf. Bay City Ed Ass’n, supra (the school district’s decision to transfer operation of its special education program to an independent third party, an intermediate school district, was not subject to a duty to bargain); United Teachers of Flint v Flint School Dist, 158 Mich App 138; 404 NW2d 637 (1986) (there was no duty to bargain over a decision to eliminate teaching positions pursuant to a reorganization); Ishpeming Supervisory Employees’ Chapter of Local 128 v Ishpeming, 155 Mich App 501; 400 NW2d 661 (1986) (there was no duty to bargain over a decision to transfer work pursuant to a reorganization effort).
However, in instances where job functions have been historically assigned interchangeably to both unit and nonunit employees, the merc has held that the mere fact that the employer assigns more of the work to one of these groups does not violate the pera or give rise to a bargaining obligation. This "exclusivity rule” originated in Fenton Area Public Schools v Council 29, AFSCME, 1976 MERC Lab Op 632, in which the employer unilaterally replaced unionized instructional aides with nonunion students. The merc dismissed the union’s unfair labor practice charge upon the basis of its finding that the work in question had not been exclusively performed by the instructional aides.
Subsequently, in Southfield v Police Officers Ass’n, 1980 MERC Lab Op 110, the police officers’ union alleged that the function of guarding prisoners had been improperly transferred to personnel outside of the bargaining unit. The merc dismissed the charge, noting that the "jailer’s work” had *180been performed by a mixed group of deputized and civilian personnel within the police department. Id. at 113.
In Detroit Police Dep’t v Detroit Police Lieutenants & Sergeants Ass% 1980 MERC Lab Op 663, the merc reconsidered and seemingly abandoned the exclusivity rule. The case involved the transfer of over fifty percent of the investigative work from members of the Detroit Police Lieutenants and Sergeants Association to patrolmen outside the bargaining unit. The merc affirmed the hearing referee’s finding of an unfair labor practice:
The earlier de minimus [sic] presence of patrolmen in the investigative function of the ios [Investigative Operative Section] does not constitute a justification for the continued wholesale erosion of bargaining unit work traditionally performed by members of Charging Party, [id. at 665.]
But the Court of Appeals reversed in an unpublished opinion per curiam and remanded the case with direction that the merc consider the exclusivity rule:
In the instant case, the merc opinion cited only the fact that the number of patrolmen in the ios [Investigative Operations Section] had risen from 3.5 percent in 1974 to 57 per cent in 1979, in support of its finding that "the investigative work of the ios division has been the traditional province of sergeants and lieutenants.” These facts are not sufficient to support the critical finding that investigative work is exclusively dplsa bargaining unit work.
Further, the record indicates that the dplsa submitted the question of whether investigative work should be the exclusive province of the dplsa to [1969 PA] 312 arbitration in 1977-1978 . . . [d]espite the recognition that the Act *181312 arbitrator had in essence found that investigative work was not the exclusive province of the dplsa, the hearing referee premised the remainder of his decision on the question whether "the unilateral assignment of bargaining unit work of employees represented by one union” to members of another union is an unfair labor practice. Thus, the hearing referee also made a finding that such work is bargaining unit work without a "concise and explicit statement of the underlying facts supporting” that finding. MCL 24.285; MSA 3.560(185).
It is axiomatic that the crux of this entire case is whether investigative work is dplsa bargaining unit work. If it is, then the city could not unilaterally reassign such work to patrol officers who are not members of the dplsa bargaining unit. If it isn’t bargaining unit work, then the city need not bargain at all on the question. Thus, adequate findings of fact on this question are critical. [Detroit Police Lieutenants & Sergeants Ass’n, supra.]
The merc has subsequently reaffirmed and repeatedly applied the exclusivity rule "to cases where unilateral transfer of bargaining unit work has been alleged because the rationale of the Court in [Detroit Police Lieutenants & Sergeants Ass’n] was sound.” Southfield v Southfield Police Officers Ass’n, 1985 MERC Lab Op 1025, 1029. See, e.g., St Joseph Co v Police Officers Ass’n, 1988 MERC Lab Op 524; Livonia v Police Officers Ass’n, 1986 MERC Lab Op 948; Richmond Community Schools v MEA/NEA Local 1, 1986 MERC Lab Op 850; Grand Rapids Public Schools v Ed Ass’n, 1986 MERC Lab Op 560; Ludington Area Schools v Ed Ass’n, 1986 MERC Lab Op 502; Sheriff of Iosco Co v Police Officers Ass’n, 1986 MERC Lab Op 443; Flint School Dist v United Teachers of Flint, 1985 MERC Lab Op T071; Southñeld v Southñeld Police Officers Ass’n, supra; Livonia Public Schools v Ed *182Ass’n, 1985 MERC Lab Op 550; Schoolcraft Community College v Ass’n of Office Personnel, 1985 MERC Lab Op 253; Dearborn v Alcamo, 1984 MERC Lab Op 78; East Detroit v Police Officers Ass’n, 1982 MERC Lab Op 1442; Southfield v Police Officers Ass’n, 1980 MERC Lab Op 110; Fenton Area Public Schools v Council 29, 1976 MERC Lab Op 632.
The opinion of the Court of Appeals in the instant case acknowledges that "the exclusivity rule finds support in decisions of merc.” 162 Mich App 734, n 1. Nevertheless, in the absence of any published Michigan appellate court opinion approving the exclusivity rule, the panel rejected the merc’s position as having "no basis in law,” and turned instead to federal decisions interpreting the analogous provisions of the National Labor Relations Act as "persuasive authority” in resolving the issue at hand. Id. at 732-733. The panel chose to follow the "adverse impact” test set forth in Westinghouse Electric Corp, supra. There, the nlrb, in dismissing a complaint with respect to unilateral subcontracting, announced the following standard:
[W]here the Board has found unilateral contracting out of unit work to be violative of Section 8(a)(5) and (1), it has invariably appeared that the contracting out involved a departure from previously established operating practices, effected a change in conditions of employment, or resulted in a significant impairment of job tenure, employment security, or reasonably anticipated work opportunities for those in the bargaining unit. [150 NLRB at 1576. See also AMCAR, supra; Olinkraft, Inc v NLRB, 666 F2d 302 (CA 5, 1982).]
The "adverse impact” test is but one of several *183tests developed by the federal courts in determining whether the diversion of unit work is a mandatory subject of bargaining. In Fibreboard Paper Products Corp v NLRB, 379 US 203, 215; 85 S Ct 398; 13 L Ed 2d 233 (1964), the Supreme Court held that an employer’s unilateral decision to contract out maintenance work previously performed by union members was a mandatory subject of bargaining. The Court emphasized that its holding was limited to the particular facts before it.
In First Nat'l Maintenance Corp v NLRB, 452 US 666, 679; 101 S Ct 2573; 69 L Ed 2d 318 (1981), the Court held that an employer’s decision to shut down part of a business solely for economic reasons would require bargaining only "if the benefit, for labor-management relations and the collective-bargaining process, outweighs the burden placed on the conduct of the business.” The Court cautioned that it expressed no view as to other types of management decisions. Id. at 686, n 22. Thus, the Court once again narrowly limited its holding.
In Otis Elevator Co, 269 NLRB 891; 115 LRRM 1281 (1984), the board relied on the analysis of Justice Stewart’s concurrence in Fibreboard, supra at 223, wherein he reasoned that "management decisions which are fundamental to the basic direction of a corporate enterprise or which impinge only indirectly upon employment security” were beyond the scope of the duty to bargain. Applying this rationale to a plant-closure situation, the nlrb in Otis, held that "the critical factor to a determination of whether the decision is subject to mandatory bargaining is the essence of the decision itself, i.e., whether it turns upon a change in the nature or direction of the business or turns upon labor costs; not its effect on employees nor a union’s *184ability to offer alternatives.” 269 NLRB 892 (emphasis in original).3
This Court has had occasion to review the federal tests, including Fibreboard, First Nat’l, and Otis, and we have noted that the holdings of those cases were strictly limited to their facts. See Bay City, supra at 380; Local 1277, supra at 658-659; Detroit Police Officers Ass’n, supra at 98-99, n 9. It is evident that no single test covers the whole spectrum of management decisions involving the transfer or diversion of unit work. Thus, federal precedent regarding private sector labor law, while "helpful,” is not "controlling.” Detroit Police Officers Ass’n, supra at 92. Federal precedent is relevant and persuasive only to the extent it is based on similar facts and circumstances and best effectuates the policy of the pera. Detroit Fire Fighters Ass’n v Detroit, 408 Mich 663; 293 NW2d 278 (1980).
In the instant case, the tests formulated by the federal courts and the nlrb to determine whether there exists a duty to bargain over the diversion of bargaining unit work in the private sector are inappropriate for use in the present context. A common thread which runs through all of the federal analyses is the underlying assumption that the disputed work which is being diverted away in one way or another from the bargaining unit is, in fact, bargaining unit work. Westinghouse, for example, involved subcontracting of what was conceded to be bargaining unit work. Similarly, in AMCAR, the "adverse impact” test was applied *185only to those duties which had earlier been found by the nlrb to be unit work.
The instant case, by contrast, involves a more basic question. Here, the disputed work had been interchangeably performed by more than one bargaining unit, thereby raising a real question as to whether the transferred duties are in fact "bargaining unit work.” This factual difference is critical.
It seems elementary that a prerequisite to any determination concerning a duty to bargain about the transfer of work is a finding that the work is "bargaining unit work.” The exclusivity rule developed by the merc recognizes that before a bargaining unit may lay sole claim to a particular work assignment, the unit must establish that the work was performed exclusively by its unit members. If the work has not been assigned exclusively to one unit, then there is no obligation on the part of the employer to bargain before shifting duties among the employees to which the work has been assigned. The exclusivity rule represents the logical first step in a duty-to-bargain analysis.
The exclusivity rule is a reasoned interpretation of the pera and a sensible solution to what otherwise would be, for the employer, an insoluble "Catch-22” situation. The exclusivity requirement goes to the very heart of the parties’ bargain. It reinforces the bargaining process by recognizing that in the absence of a negotiated agreement which requires that work will be performed exclusively by one unit, employers and employee representatives have, in effect, agreed that the employer is free to assign work. Very significant are the ramifications for the public employer if the exclusivity rule were not given credence. In such an event, the public employer’s transfer of nonexclusive work would always be subject to challenge by *186whichever unit loses the work. In the present case, for example, public safety technicians, police officers, and command officers all may have a claim to the disputed work. It is not unrealistic to expect that the employer would become snared in inter-union rivalries.
The potential for perpetual conflict between competing bargaining units also raises the specter of long delays and escalating public expense caused by impasse-resolution procedures that are peculiar to the pera. Unlike the nlra, a public employer under the state statute is not free to implement its final offer after bargaining parties reach an impasse. The public employer must first engage in, and exhaust, either arbitration or a fact-finding procedure established by 1969 PA 312, MCL 423.231 et seq.; MSA 17.455(31) et seq., MCL 423.25; MSA 17.454(27). Additionally, § 13 of Act 312, MCL 423.243; MSA 17.455(43), specifically requires the public employer to maintain the status quo pending the Act 312 arbitration process.
In the present context, the public employer would be required to refrain from transferring work assignments between two units which have both previously performed the work until after the completion of the Act 312 process. The public employer’s hands would be tied with regard to simple work assignments. Since, as in the instant case, several bargaining units and different unions are involved, multiple arbitrations could be generated over the same work assignment.
Under the exclusivity rule, if particular work has been performed interchangeably by employees in several bargaining units, and the public employer has not been limited by the terms of a collective bargaining agreement, the public employer is able "to assign according to the expertise *187required by the work . . . Livonia, supra at 951. The merc standard, unlike the federal "adverse impact” rule, takes into account the significant differences in the statutory schemes regarding the resolution of disputes and provides for the efficient allocation of scarce public resources by minimizing time-consuming and expensive challenges to the transfer of work where there has been an overlap in the performance of job duties by a multiplicity of bargaining units.
The association argues that the exclusivity rule threatens the viability of the bargaining unit because the rule is at odds with another principle followed by the merc. The merc has consistently held that no violation of the duty to bargain will be found if the work removed is de minimis in the context of the unit’s work load. See, e.g., Ludington Area Schools, supra; Grant Public Schools v Grant Ed Ass’n, 1983 MERC Lab Op 117; Troy (Police Dep’t) v Troy Command Officers Ass'n 1982 MERC Lab Op 667. The association asserts that the exclusivity rule, when applied in conjunction with the de minimis principle, allows an employer to unilaterally remove a de minimis portion of the work without violating the duty to bargain and later remove the remainder of the work on the basis of the justification that the transferred work is no longer exclusively that of the affected bargaining unit. In other words, object too soon and the effect is de minimis; object too late, and it is no longer exclusive bargaining work. The appellee foresees extensive erosion of the bargaining unit as a result of application of the exclusivity rule.
However, as the city points out, the merc has held that a prior de minimis removal of unit work does not transform once exclusive work into nonexclusive work. In Southfield v Police Officers *188Ass’n, 1985 MERC Lab Op 904, 908, the commission held:
The Employer also argues that it is relieved of the duty to bargain since work in the Property Room was not exclusive bargaining unit work. It is true that the Commission has found that when the disputed work is not exclusive bargaining unit work there is no bargaining obligation should the Employer shift duties to nonunit employees. City of Dearborn, 1984 MERC Lab Op 78; City of East Detroit, 1982 MERC Lab Op 1442. However, as far as this record reveals, the Property Room position has been exclusive bargaining unit work for at least the last six or seven years. The fact that the pst [Public Safety Technician] received occasional minimal assistance from her supervisor or a ceta worker does not change this fact.
As the merc pointed out in the instant case:
The mere fact that a job has been assigned to a member of another bargaining [unit] sometime in the past does not mean that the work is not bargaining unit work, as we held in St Joseph Public Schools [v St Joseph Ed Ass’n], 1985 MERC Lab Op 454. Where the work has been assigned exclusively to a unit member for a substantial period of time, and there is no agreement that said assignment is temporary, the Employer has an obligation to bargain before transferring the work. [1985 MERC Lab Op 1030.]
Thus, any possibility that the exclusivity rule will be used as a tool by a public employer to whittle away the domain of a particular bargaining unit is tempered by the merc’s recognition that exclusivity is a flexible concept which must take into account the relationship of the affected bargaining units vis-á-vis the employer on a case-by-case basis.
*189IV
In the instant case, there is no dispute that public safety technicians and other civilian employees, as well as police officers, had been assigned interchangeably to the crime prevention bureau and the auto pound for a period of several years. The association does not dispute that police officers did not exclusively perform these assignments in the past. Given our affirmation of the exclusivity rule, we conclude that the merc properly ruled under the present facts that the city’s assignment of the nonexclusive work did not constitute an unfair labor practice.
For the above-stated reasons, we reverse the decision of the Court of Appeals and reinstate the decision of the merc.
Riley, C.J., and Levin and Brickley, JJ., concurred with Griffin, J.MCL 423.201 et seq.; MSA 17.455(1) et seq.
Section 15 of the pera, MCL 423.215; MSA 17.455(15) provides:
A public employer shall bargain collectively with the representatives of its employees as defined in section 11 and is authorized to make and enter into collective bargaining agreements with such representatives. For the purposes of this section, to bargain collectively is the performance of the mutual obligation of the employer and the representative of the employees to meet at reasonable times and confer in good faith with respect to wages, hours, and other terms and conditions of employment, or the negotiation of an agreement, or any question arising thereunder, and the execution of a written contract, ordinance or resolution incorporating any agreement reached' if requested by either party, but such obligation does not compel either party to agree to a proposal or require the making of a concession.
See also Local 2179, United Steelworkers of America v NLRB, 822 F2d 559 (CA 5, 1987); Plymouth Stamping Div, Eltec Corp, 286 NLRB No 85; 127 LRRM 1021 (November 19, 1987); Litton Microwave Cooking Products Div, 283 NLRB 973; 125 LRRM 1081 (1987); Hawthorn Mellody, Inc, 275 NLRB 339; 119 LRRM 1079 (1985); GarWoodDetroit Truck Equip Co, 274 NLRB 113; 118 LRRM 1417 (1985); Columbia City Freight Lines, Inc, 271 NLRB 12; 116 LRRM 1311 (1984).