(dissenting). We are asked to decide in this case whether the determination of a wife’s dependency for the purpose of calculating an injured worker’s wage-loss compensation benefits may be relitigated when the statutory presumption of dependency applicable at the time of an earlier determination is now alleged to be unconstitutional. The majority, sub silentio, overrules Hlady v Wolverine Bolt Co, 393 Mich 368; 224 NW2d 856 (1975), and Gose v Monroe Auto Equipment Co, 409 Mich 147; 294 NW2d 165 (1980), while concluding that res judicata does not bar a collateral attack on a final award in workers’ compensation proceedings on the basis of an intervening change in the law. The abandonment of the carefully crafted doctrine of res judicata in workers’ compensation proceedings is unsupported by treatise, statute, or prior decision of this Court. The dismissal of defendants’ petition for benefit reduction was properly granted. I would affirm the judgment of the workers’ compensation appeal board.
i
Ronald Pike, already adjudicated a disabled worker, alleged that he qualified as totally and permanently disabled in late fall of 1979. He petitioned the Bureau of Workers’ Disability Compen*610sation for total and permanent disability benefits on May 14, 1979. The City of Wyoming and the Second Injury Fund contested the claim.
Mr. Pike’s petition was put to the test in proceedings before the bureau on October 20, 1980. With the assistance of counsel, Ronald Pike prevailed. A decision of the hearing referee, Erwin Johnson, mailed May 21, 1981, ruled that Mr. Pike was indeed totally and permanently disabled. The defendants chose not to appeal that decision. Thus, under § 851 of the act,1 the decision of the bureau became final on June 4, 1981.
Ronald Pike’s final award of wage loss benefits included five dollars per week for the dependency of his wife. Mrs. Pike’s dependency had not been factually established during the litigation before the bureau because the act provides that Mrs. Pike is "conclusively presumed” a dependent, MCL 418.353(l)(a)(i); MSA 17.237(353)(l)(a)(i). The defendants chose not to contest the validity of that provision in those proceedings.
On July 11, 1983, two years after the order of the bureau was final, the defendants attempted to reopen this litigation. The defendants claimed that the conclusive presumption of Mrs. Pike’s dependency violated the Equal Protection Clause of US Const, Am XIV. Quite reasonably, both the bureau2 and the workers’ compensation appeal board3 refused to entertain further litigation of this matter. Both cited the final, unappealed order of the bureau and the doctrine of res judicata. The Court of Appeals denied the defendants’ application for leave to appeal.4_
*611A
Today, a majority of this Court holds that the conclusive presumption of Mrs. Pike’s dependency is unconstitutional. The same majority holds, as an afterthought, that res judicata does not preclude the reopening of this litigation by the defendants. In doing so, the majority abandons the principle of finality in workers’ compensation proceedings. Henceforth, the final orders of the bureau, the appeal board and presumably even the orders of this Court, are valid only for that period of time required for a change in the decisional law allegedly entitling a losing party to relief in a new petition before the bureau.
The change in decisional law to which the defendant here refers is this Court’s ruling in Day v W A Foote Memorial Hosp, 412 Mich 698, 703; 316 NW2d 712 (1982), in which we found the statutory presumption of dependency for widows in MCL 418.331(a); MSA 17.237(331)(a)5 violative of the Equal Protection Clause as applicable under the Fourteenth Amendment.6
The majority accepts this analysis and concludes that the statute is unconstitutional without first answering whether defendants can raise this question by a collateral attack on a final order. It should be obvious that the status of plaintiff’s *612wife’s dependency can become an issue in this case only if two preconditions are satisfied; first, that these defendants can challenge the constitutionality of § 353(l)(a)(i) and, second, that § 353(l)(a)(i) is unconstitutional. It is simply a non sequiter to conclude, as does the lead opinion, that the gender-based presumption is unconstitutional and "in light of that holding” to then consider "whether res judicata bars redetermination of the unappealed finding that plaintiff’s wife was a dependent at the time of plaintiff’s injury.” Ante, p 595.
The majority does not contest the applicability of the doctrine of res judicata in workers’ compensation cases. Nor does the majority explicitly confront the fact that this Court has repeatedly held that an intervening change in the law is not an exception to res judicata. Gose and Hlady, supra. That doctrine prevents the relitigation of facts and law "between the same parties or their privies.” Curry v Detroit, 394 Mich 327, 331; 231 NW2d 57 (1975), citing Tucker v Rohrback, 13 Mich 73 (1864). Its purpose is to "relieve parties of the cost and vexation of multiple lawsuits, conserve judicial resources, and, by preventing inconsistent decisions, encourage reliance on adjudication.” Allen v McCurry, 449 US 90, 94; 101 S Ct 411; 66 L Ed 2d 308 (1980). In short, res judicata seeks to lend fairness and finality to the law. See also Hackley v Hackley, 426 Mich 582, 585; 395 NW2d 906 (1986).
In Michigan, the scope of the doctrine is well defined. It applies not only to issues of fact and law which were actually litigated and decided, but also to any issue which might have been litigated at that time. Curry, supra, p 332; Gursten v Kenney, 375 Mich 330; 134 NW2d 764 (1965). See also Hackley, supra. Therefore, if during the adjudication of *613a dispute a pertinent issue of law or fact is raised and decided, or properly should have been raised, res judicata will bar the relitigation of that issue in a subsequent action.
The rule of res judicata appeals to common sense and is familiar to all students of the law. As formulated in 1 Restatement Judgments, 2d, § 18(2), p 152, the rule provides:
In an action upon the judgment, the defendant cannot avail himself of defenses he might have interposed, or did interpose, in the first action.
It is indisputable that the law of judgments applies to workers’ compensation. The Legislature has provided:
Any party may present a certified copy of an order of a hearing referee, the director or the board in any compensation proceeding to the circuit court of the circuit in which the injury occurred, or to the circuit court of the county of Ingham if the injury was sustained outside this state. The court, after 7 days’ notice to the opposite party or parties, shall render judgment in accordance therewith unless proof of payment is made. The judgment shall have the same effect as though rendered in an action tried and determined in the court and shall be entered and docketed with like effect. [MCL 418.863; MSA 17.237(863). See also Theodore v Packing Materials, 396 Mich 152; 240 NW2d 255 (1976), and Gose, supra.]
The parties agree that the issue of law regarding the constitutionality of § 353(l)(a)(i) was not raised in the original unappealed action. There is no question that the constitutionality of § 353(l)(a)(i) was pertinent in the first proceeding and that the defendants’ failure to raise the issue is not excusable. In light of the fact that defendants now chose *614to contest the issue, it cannot be successfully claimed that a constitutional challenge at the first proceeding would have been unusual or burdensome. The issue was clearly foreseeable.
In Wengler v Druggists Mutual Ins Co, 446 US 142; 100 S Ct 1540; 64 L Ed 2d 107 (1980), on which we relied in Day, supra, the Court struck down a widow dependency provision similar to that found in § 331(a) as violative of the Equal Protection Clause. Wengler had been the law for over one year when the issue of dependency in this case was contestable. Additionally, given the fact that the United States Supreme Court, prior to Wengler, had invalidated at least six statutes containing, or practices founded upon, gender-based classifications,7 it could not be argued that a gender-based challenge at the initial proceedings would have been either novel or extraordinary.8 Moreover, the defendants were clearly bound by a rule articulated five years before the final order in this case (reaffirmed by six members of this Court three years before that order) that a change in decisional law does not permit a relitigation of a final award of compensation benefits, Hlady, supra; Gose, supra.
In Hlady, p 380, we observed in words equally applicable to these defendants,_
*615Plaintiff may not concede an issue, necessarily determinative of and included in the judgment of this Court, and then, after another has successfully raised the issue she did not wish to contest, ask the Court again for relief. The doctrine of res judicata bars this from happening. Mary Hlady could have as easily raised this issue as Peter Van Dorpel. It was, in fact, incumbent upon her to do so if she wished to avail herself of that interpretation.
In simple fact, the defendants ask us to permit an attack on a final award despite the fact that the constitutionality of § 353(l)(a)(i) was not raised before the referee and the defendants opted not to appeal to the wcab, the Court of Appeals, or this Court. Only two years after this case finally was decided, did the defendants seek to contest the validity of § 353(l)(a)(i). "The doctrine of res judicata bars this from happening.” Hlady, supra, p 380.
B
As I have previously noted, no one explicitly contests the applicability of the doctrine of res judicata in workers’ compensation cases. The lead opinion ostensibly reaffirms application of the doctrine when it states:
That res judicata principles are applicable in the workers’ compensation context has been recognized by this Court. Hlady v Wolverine Bolt Co, 393 Mich 368, 375; 224 NW2d 856 (1975); Theodore v Packing Materials, Inc, 396 Mich 152, 158; 240 NW2d 255 (1976); Gose v Monroe Auto Equipment Co, 409 Mich 147, 161; 294 NW2d 165 (1980). [Ante, p 595.]
Nevertheless, it fails to acknowledge that our prior *616decisions do not permit today’s result and makes no effort to distinguish or expressly overrule them.
The majority fails to acknowledge that the facts of Hlady are indistinguishable from those of this case. Hlady lost four fingers in a punch press accident and received the statutory one hundred weeks of compensation for the specific loss of her hand. See MCL 418.361(2)(h); MSA 17.237(361)(2)(h) (now 215 weeks). At expiration of the one-hundred-week statutory period, Hlady sought further disability compensation. Despite her continuing disability in fact, Hlady was denied continuing disability benefits. See Hlady, supra, p 373. Subsequently, Hlady again sought continuing disability benefits on the basis of an alleged change in decisional law allowing continuing benefits after the expiration of the statutory period for specific losses. This Court denied continuing benefits, explaining:
Mary Hlady’s physical condition has not changed since her 1945 injury. The only change has been in the law applied to cases of this nature. However, it has long been the law of this state, starting with the leading case of Jacobson v Miller, 41 Mich 90; 1 NW 1013 (1879), that the doctrine of res judicata applies not only to facts previously litigated, but also to points of law which were necessarily adjudicated in determining and deciding the subject matter of the litigation. [Hlady, supra, p 376.]
There is no principled distinction between Hlady and the instant case. In both cases, unsuccessful litigants have sought to reopen a final workers’ compensation decision to take advantage of an alleged intervening change of law. It is plain that the majority, sub silentio, overrules Hlady.
Theodore v Packing Materials, supra, also cited *617by the lead opinion, in fact holds that the Court will permit a redetermination of dependency where a statutory exception applies, but that res judicata bars an unappealed dependency determination that does not fall within a statutory exception. In Theodore, the Court reviewed a collateral attack by a second petition initiated after the defendant had failed to appeal the initial hearing referee’s decision that the natural children of a deceased employee were conclusively presumed to be his dependents. The defendant’s petition to terminate death benefits alleged both that the children had been legally adopted prior to the employee’s death and that they had reached the age of sixteen, the date on which the presumption terminated under law. Notwithstanding the fact that we stated that "in future cases” adopted children should not be found to be dependents, the Court held that the referee’s ruling had become final and res judicata barred the defendant’s attempts to terminate, on grounds of adoption, payments owed to the children up to the age of sixteen. On the other hand, pursuant to the express language in the statute, the Theodore defendant was allowed to challenge the fact that the recipients were over sixteen and no longer dependents. 396 Mich 154.9 ___
*618Similarly, in Gose, supra, a five-member majority of this Court10 refused to allow relitigation of the plaintiffs claim for benefits on the basis of insanity when it had been previously fully and finally litigated on the basis of a physical injury. In the companion case of Sanders v General Motors Corp, 409 Mich 147; 294 NW2d 165 (1980), six members of this Court refused, in the absence of a change of physical condition, to allow the plaintiff to relitigate her claim for total and permanent disability benefits on the basis of "a subsequent change in the law,” Gose, supra, p 181 (Williams, J., and Moody, J., concurring).
Thus, under the prior rulings of this Court, the doctrine of res judicata bars relitigation of this matter.
c
En route to its conclusion, the majority also observes that the workers’ compensation act provides for modification of an award under certain circumstances. However, the exceptions recognized by the Legislature do not support the majority’s conclusion. Thus, the majority does not acknowledge the fact that the act provides for modification of a disability award only under clearly defined circumstances and that the act does not provide for redetermination of dependency in this circumstance.
*619Initially the majority fails to recognize that the Legislature does not characterize dependency as continuously contestable. Unlike MCL 418.351; MSA 17.237(351), which allows for the redetermination of the question of total and permanent disability after a period of eight hundred weeks on the basis of a change of facts, the Legislature has not provided for general redetermination of dependency questions. In fact, the Legislature has expressly provided that all issues of dependency are to be determined: "as the fact may be at the time of the injury .11
The clear intention of the Legislature is that issues of dependency are not to be redetermined except in the case of self-support of a minor between sixteen and eighteen years of age or the divorce or death of a dependent spouse, § 353(2). No other exception is provided for the relitigation of dependency. Thus, the act provides no support for the conclusion that a legislative distinction between eligibility and the level of benefits to which a claimant is entitled permits the relitigation of issues concerning the "amount” of one’s benefits. In fact, this conclusion ignores the legislative direction that issues of dependency are to be determined "as the fact may be at the time of the injury.”12
The majority’s construction of § 353 produces the incongruous result that dependency resolu*620tions under § 353(l)(b) are made as the facts "may be at the time of the injury,” but dependency based on the legislatively created presumption is indefinitely contestable. This construction also is inconsistent with the parallel dependency provisions for death benefit recipients, that after likewise providing for conclusive benefits for a wife, for dependency in fact, and for specific exceptions (§§ 321, 331 and 335) provide:
Questions of dependency shall be determined as of the date of the injury to the employee, and their right to any death benefit shall become fixed as of such time, irrespective of any subsequent changes in conditions . . . (except as noted above).
There also is no basis in law for the conclusion that the principle of finality applies only to rulings as to eligibility and not to rulings regarding the amount of benefits. The case law cited by the lead opinion lends no support to the proposition that only "eligibility” is subject to the law of res judicata. Leskinen v Employment Security Comm, 398 Mich 501; 247 NW2d 808 (1976), includes no discussion of res judicata. Indeed, at the time that our decision was released in Leskinen, there had been no final decision. Res judicata could not have been at issue. The distinction between eligibility and the amount of benefits for which the majority cites Leskinen was relevant only to the Court’s discussion of earning capacity.13
Goines v Kelsey Hayes Wheel Co, 294 Mich 156; 292 NW 686 (1940), is also distinguishable in that it involved the well-established exception to res judicata in workers’ compensation proceedings for *621a change of physical condition. Moreover, no change of condition was found in Goines and therefore, even this narrow exception was held to be inapplicable. Indeed, as the facts and holding of Goines demonstrate, even if this exception were applicable, it would not apply to the amount of benefits, but to the plaintiffs eligibility.14 In my view, this narrow exception for a change of condition serves only to provide additional support for the continuing validity of the rule of res judicata.
Finally, the fundamental logical flaw in this analysis is the assumption that the rule of res judicata follows from the distinction between an entitlement and a benefit. Even if the Legislature had said, which it clearly has not, that dependency is generally contestable on a change in facts, it would not follow that a second petition could be filed on the basis of the identical facts resolved in a prior determination that had become final. The issue in this case is not whether benefit levels remain open, but rather whether the defendants may challenge this final award on the basis of an alleged change in constitutional law. As Theodore, Hlady, and Gose demonstrate, a collateral attack on the same claim and the same facts solely on the basis of a judicial decision rendered after a final nonappealed award is barred by the doctrine of res judicata. Therefore, it does not follow from the fact that the Legislature permits an issue (whether of entitlement or benefits) to remain subject to challenge on the basis of new facts, that a collateral attack is permitted on a final award on the same claim based upon the identical facts._
*622D
Turning to our prior decisions outside of the context of workers’ compensation, the lead opinion cites Socialist Workers Party v Secretary of State, 412 Mich 571, 585; 317 NW2d 1 (1982), for the rule that res judicata does not bar the relitigation of an issue previously decided when there has been a change in the law or facts upon which that issue was decided. The Socialist Workers Party majority relied on what is now § 28(2)(b) of the Restatement to find an exception to the bar of res judicata. That section reads in part:
Although an issue is actually litigated and determined by a valid and final judgment, and the determination is essential to the judgment, relitigation of the issue in a subsequent action between the parties is not precluded in the following circumstances:
(2) The issue is one of law and (a) the two actions involve claims that are substantially unrelated, or (b) a new determination is warranted in order to take account of an intervening change in the applicable legal context or otherwise to avoid inequitable administration of the laws .... [1 Restatement Judgments, 2d, § 28, p 273.]
Section 28(2)(b), however, has no bearing on this case. It is a rule of issue preclusion or collateral estoppel, rather than a restatement of the principles of claim preclusion, or merger and bar, under res judicata.15 The Restatement is quite clear on this distinction as noted in § 13:_
*623The rules of res judicata are applicable only when a final judgment is rendered. However, for purposes of issue preclusion (as distinguished from merger and bar), "final judgment” includes any prior adjudication of an issue in another action that is determined to be sufficiently firm to be accorded conclusive effect. [Id., p 132.]
When, as in this case, an award is entered in favor of the plaintiff, "the claim is extinguished and merged in the judgment and a new claim may arise on the judgment.” 1 Restatement Judgments, 2d, § 17(2), p 148. Thereafter, parties may not seek to relitigate the original claim or any part of that claim. Specifically, § 18(2) of 1 Restatement Judgments, 2d, provides:
In an action upon the judgment, the defendant cannot avail himself of defenses he might have interposed, or did interpose, in the first action. [Id., p 152.]
The lead opinion thus has failed to recognize that Socialist Workers Party does not support the conclusion that res judicata does not bar the defendant’s claim.16
*624E
Finding no support for its holding in the law of this state, the lead opinion turns to federal precedent. There is, however, no support in federal law for the conclusion that res judicata must "yield” in this situation to a change in the law. The lead opinion cites Internal Revenue Comm’r v Sunnen, 333 US 591; 68 S Ct 715; 92 L Ed 898 (1948), for this proposition, while acknowledging that "the analogy is by no means perfect,” and that the decision does not rest on this basis.
The lead opinion’s reliance on Sunnen is misplaced. In Sunnen, the United States Supreme Court held that royalty payments arising from *625certain license contracts not involved in an earlier tax proceeding, and which concerned different tax years, were "free from the effects of the collateral estoppel doctrine.” Id., p 602. Thus, Sunnen is neither binding nor persuasive precedent because it did not involve the application of res judicata. Even if we were to assume that the case at bar involved the doctrine of collateral estoppel, the Supreme Court’s decision in United States v Moser, 266 US 236, 242; 45 S Ct 66; 69 L Ed 262 (1924), clearly illustrates that the defendants’ claim must fail. In holding that the federal government was estopped from relitigating whether service as a military cadet constituted "service during the Civil War” for the purpose of calculating the claimant’s retirement benefits, the Court stated:
[A] fact, question or right distinctly adjudged in the original action cannot be disputed in a subsequent action, even though the determination was reached upon an erroneous view or by an erroneous application of the law. That would be to affirm the principle in respect of the thing adjudged but, at the same time, deny it all efficacy by sustaining a challenge to the grounds upon which the judgment was based. A determination in respect of the status of an individual upon which his right to recover depends is as conclusive as a decision upon any other matter. [Emphasis in the original, citations omitted.]
More significantly, and more recently, in United States v Stauffer Chemical Co, 464 US 165, 172-173, n 5; 104 S Ct 575; 78 L Ed 2d 388 (1984), the United States Supreme Court refused to extend the Sunnen rule beyond its applicability in tax cases "reject[ing] its general applicability outside of [sic] that context.” Thus, the lead opinion’s attempt to extend Sunnen by analogy to the facts *626in this case should be rejected. The Sunnen rule has been recognized by the United States Supreme Court to be sui generis in the context of tax litigation. The case does not provide support for the lead opinion’s construction of the applicability of res judicata in a workers’ compensation proceeding.
ii
The actual basis for the lead opinion’s conclusion appears to be neither federal or state precedent nor a legislative distinction between benefits or entitlement. Rather, the basis for the majority result appears to be the reasoning in the Hlady concurrence:
The law can be changed by legislative enactment or court decision. When the Legislature amends a statute, its applicability to a case previously adjudicated is not analyzed in terms of res judicata. The issue then is one of statutory construction: did the Legislature intend the amendment to have retroactive as well as prospective application? Where the change is effected by court decision the analysis should be the same, whether as a matter of policy the new rule of law should apply retroactively as well as prospectively. [Hlady, supra, p 387.]
This statement is in direct conflict with the majority’s articulation of the rule of res judicata in Hlady and Gose. More importantly, however, the unsupported proposition that the power of the Court is coextensive with that of the Legislature is devoid of the judicial restraint necessary for recognition of the fundamental principles of fairness and repose that are the basis for the rule of res judicata.
*627The decisions of the United States Supreme Court, as well as our own, teach the error of an ad hoc judicial policy of reopening final judgments except in the most compelling circumstances.17 The United States Supreme Court has ably articulated the policy basis for res judicata in Federated Dep’t Stores, Inc v Moitie, 452 US 394; 101 S Ct 2424; 69 L Ed 2d 103 (1981):
[T]he res judicata consequences of a final, unappealed judgment on the merits [are not] altered by the fact that the judgment may have been wrong or rested on a legal principle subsequently overruled in another case. ... "A judgment merely voidable because based upon an erroneous view of the law is not open to collateral attack, but can be corrected only by a direct review and not by bringing another action upon the same cause [of action.]” [Id., p 398.]
[W]e do not see the grave injustice which would be done by the application of accepted principles of res judicata. "Simple justice” is achieved when a complex body of law developed over a period of years is evenhandedly applied. The doctrine of res judicata serves vital public interests beyond any individual judge’s ad hoc determination of the equities in a particular case. . . . The Court of Appeals’ reliance on "public policy” is similarly misplaced. This Court has long recognized that "[p]ublic policy dictates that there be an end of litigation; that those who have contested an issue shall be bound by the result of the contest, and *628that matters once tried shall be considered forever settled as between the parties.” We have stressed that "[the] doctrine of res judicata is not a mere matter of practice or procedure inherited from a more technical time than ours. It is a rule of fundamental and substantial justice, 'of public policy and of private peace,’ which should be cordially regarded and enforced by the courts . . . [Id., p 401. Citations omitted. Emphasis added.]
It is in the nature of decision making, whether judicial or legislative, that lines must be drawn. Thus, there is an unfortunate but inescapable arbitrary aspect to all rules of finality, including res judicata, waiver, or the application of statutory amendment. Perfect justice may not be possible in each case. What is possible is the fairness, repose and predictability that results when all are subject to the same rules. What is also possible, and of equal importance, is a certainty in the law to which all may conform their conduct. These qualities are lost when the rules of finality are changed in each proceeding. Confidence and respect for the courts erodes when the rules are changed with each new set of litigants before the court or with each new announcement by a court as to why res judicata is not "appropriate” in a given case. (Brickley, J., concurring, ante, pp 606-607.) It is as uncertain that perfect justice may be gained in any particular case by deviating from the established rules of finality as it is that any majority of this or any court is able to define perfect justice. Here, for example, the majority forecloses the presumed dependents under § 353(l)(a)(i) from ever litigating the constitutionality of the provision and, indeed, even from contesting the lead opinion’s unique rule of res judicata.
Historically, the application of res judicata has been determined by reference to an overriding *629institutional policy of fairness and finality. If that policy is to be abandoned, some justification must be identified apart from the current judicial view of the substance of law upon which the defense is based. Otherwise, there is no law of res judicata. The majority completely fails to identify any such policy in the instant case.
Giving due deference to the principle of separation of powers, we must presume that each legislative enactment is based upon an important social policy. It is undisputed and must not be forgotten that Ronald Pike has been adjudicated totally and permanently disabled. For these severe cases, the Legislature has presented a conclusive presumption of total and permanent disability for eight hundred weeks. See MCL 418.351(2); MSA 17.237(351)(2). Within that time frame, not even a change of physical condition presents a basis for reopening a final order. It cannot be seriously contended that the Legislature nevertheless envisioned a reopening of the issue of Mrs. Pike’s dependency at five dollars per week.18_
*630It is ironic that the object of this alteration of the rule of finality in workers’ compensation proceedings is a worker whom the Legislature sought most to protect from the hazards of relitigation. Indeed, it is doubly ironic, since the issue which the defendants seek to raise also was given legislative protection from protracted litigation, by way of a conclusive presumption. The majority has overridden this policy and consigned the rule of res judicata to ad hoc determination of "fairness” by this Court. On policy grounds, today’s decision is simply indefensible.
There may be matters of public policy so extraordinary as to justify a departure from res judicata principles. However, a court’s vague notion of "fairness”19 — though motivated by benevo*631lence in a particular case — does not justify the substantial injustice that results when finally decided cases are reopened. Such a view negates the expectations of the bar on which client advice is predicated and corrupts the decision-making process of a court.
The doctrine of res judicata bars the relitigation of the dependency issue. The defendants’ petition for a benefit reduction was properly dismissed. The decision of the workers’ compensation appeal board should be affirmed.
Cavanagh, J., concurred with Boyle, J. Archer, J. I concur in Justice Boyle’s opinion through part I-A.MCL 418.851; MSA 17.237(851).
Order of the hearing referee, Erwin Johnson, mailed December 8, 1983.
1986 WCABO 63.
Order of the Michigan Court of Appeals dated May 9,1986.
MCL 418.331; MSA 17.237(331) provides in part:
The following persons shall be conclusively presumed to be wholly dependent for support upon a deceased employee:
(a) A wife upon a husband with whom she lives at the time of his death, or from whom, at the time of his death, a hearing referee or worker’s compensation magistrate, as applicable, shall find the wife was living apart for justifiable cause or because he had deserted her.
See Wengler v Druggists Mutual Ins Co, 446 US 142; 100 S Ct 1540; 64 L Ed 2d 107 (1980).
Califano v Goldfarb, 430 US 199; 97 S Ct 1021; 51 L Ed 2d 170 (1977); Craig v Boren, 429 US 190; 97 S Ct 451; 50 L Ed 2d 397 (1976); Stanton v Stanton, 421 US 7; 95 S Ct 1373; 43 L Ed 2d 688 (1975); Weinberger v Wiesenfeld, 420 US 636; 95 S Ct 1225; 43 L Ed 2d 514 (1975); Frontiero v Richardson, 411 US 677; 93 S Ct 1764; 36 L Ed 583 (1973); Reed v Reed, 404 US 71; 92 S Ct 251; 30 L Ed 2d 225 (1971).
See also 4 Davis, Administrative Law (2d ed), § 26:6, pp 434-441. By statute, the bureau is empowered to resolve "[a]ny dispute or controversy concerning compensation or other benefits . . . .” MCL 418.841(1); MSA 17.237(841X1). While admittedly constitutional questions "are beyond the purview of the wcab,” Williams v Hofley Mfg Co, 430 Mich 603, 624, n 27; 424 NW2d 278 (1988), they are not beyond the purview of the Court of Appeals or this Court.
The relevant sections of the statute in Theodore, similar to those of the current act § 353(l)(a)(ii), provided that children under the age of sixteen, unless physically or mentally incapacitated, were entitled to the presumption of dependency under the act subject to the exception that on attaining the age of sixteen, the issue of dependency may he reconsidered. Thus, the Legislature specifically excepted a child’s dependency status redetermination upon the occurrence of certain triggering events. No such redetermination, however, is provided for under the act in the case of a conclusively dependent spouse. Under § 353(l)(a)(i), the wife of an injured employee is conclusively presumed to be the dependent of her injured husband regardless of any future change in her status. Consequently, our ruling in Theodore actually supports the rule that, apart from statutorily provided exceptions, res judicata is applicable to workers’ compensation pro*618ceedings and operates in this case to bar the relitigation of plaintiffs wife’s dependency when no provision under the act provides for the relitigation of this issue.
Theodore and Hlady also demonstrate that it is immaterial whether the parties actually litigated the issue or did not do so because of § 353(l)(a)(i).
A sixth member of the Gose Court, Justice Williams, agreed that res judicata was generally applicable in workers’ compensation proceedings, but believed that it was not applicable under the facts presented.
MCL 418.353(l)(b); MSA 17.237(353)(l)(b). This rule is consistent with MCL 418.341; MSA 17.237(341), which requires that dependency issues concerning death benefit recipients are decided as of the date of injury to the employee.
This directive is not contradicted by the conclusion of the lead opinion that § 353(l)(b) applies only if the dependency presumption in § 353(l)(a)(i) is inapplicable. Rather, the full text of § 353 expresses the legislative view that, regardless of whether dependency is found through the presumption in § 353(l)(a)(i) or through a factual determination under § 353(l)(b), dependency issues are to be finally decided no later than the appellate stage before the wcab.
The citation of Medacco v Campbell, Wyant & Cannon Foundry Co, 48 Mich App 217, 226; 210 NW2d 360 (1973), is similarly misplaced because it too only identifies the significance of an injured worker’s wage-earning differential as affecting wage-earning capacity as opposed to one’s eligibility for benefits.
Similarly, in Houg v Ford Motor Co, 288 Mich 478; 285 NW 27 (1939), Murray v Ford Motor Co, 296 Mich 348; 296 NW 284 (1941), Webber v Steiger Lumber Co, 322 Mich 675; 34 NW2d 516 (1948), Dyer v McQuistion, 273 Mich 327; 263 NW 73 (1935), and Sauch v Studebaker Corp, 232 Mich 147; 205 NW 120 (1925), also cited by the majority, the issue was a change of physical condition.
See Hlady, supra, p 377, citing with approval the decision of the United States Supreme Court in Partmar Corp v Paramount Pictures Theatres Corp, 347 US 89, 90-91; 74 S Ct 414; 98 L Ed 532 (1954), which distinguished the rules of res judicata and collateral estoppel:
" 'We have often held that under the doctrine of res judicata *623a judgment entered in an action conclusively settles that action as to all matters that were or might have been litigated or adjudged therein. But a prior judgment between the parties has been held to operate as an estoppel in a suit on a cause of action different from that forming the basis for the original suit "only as to those matters in issue or points controverted, upon the determination of which the finding or verdict was rendered.” This latter aspect of res judicata is the doctrine of collateral estoppel by judgment, established as a procedure for carrying out the public policy of avoiding repetitious litigation.’ ” [Emphasis added.]
Issue preclusion under the Restatement is set out in § 27:
*624When an issue of fact or law is actually litigated and determined by a valid and final judgment, and the determination is essential to the judgment, the determination is conclusive in a subsequent action between the parties, whether on the same or a different claim. [Id., p 250.]
The introductory note to this title underscores the necessary distinction between issue preclusion and res judicata, stating that issue preclusion is applicable only when "the claim is not precluded by the doctrines of merger or bar.” Id., p 249. The rules of merger and bar are set out in § 17:
A valid and final personal judgment is conclusive between the parties, except on appeal or other direct review, to the following extent:
(1) If the judgment is in favor of the plaintiff, the claim is extinguished and merged in the judgment and a new claim may arise on the judgment (see § 18);
(2) If the judgment is in favor of the defendant, the claim is extinguished and the judgment bars a subsequent action on that claim (see § 19);
(3) A judgment in favor of either the plaintiff or the defendant is conclusive, in a subsequent action between them on the same or a different claim, with respect to any issue actually litigated and determined if its determination was essential to that judgment (see § 27). [Id., p 148.]
Under the Restatement view, a judgment for either a plaintiff or a defendant is conclusive with respect to any essential point actually litigated.
We realize that in certain instances of a compelling nature public policy may require the recognition of exceptions to res judicata. See, e.g., 18 Wright, Miller & Cooper, Federal Practice and Procedure, § 4415, pp 121-135, citing McCarty v First of Georgia Ins Co, 713 F2d 609, 612-613 (CA 10, 1983) (res judicata not applicable when fraudulent concealment of true facts by defendant prevents plaintiff from showing cause of action); Fehlhaber v Fehlhaber, 681 F2d 1015, 1027 (CA 5, 1982) (res judicata not applicable when enforcement of prior judgment would amount to a denial of due process); MCR 2.612(C) (grounds for relief from judgment).
The majority, perhaps inadvertently, has created today a serious barrier to plaintiffs in these proceedings. Generally, plaintiffs’ counsel in workers’ compensation proceedings are retained on a contingency fee basis in the amount of thirty percent of the accrued amount of a final bureau order. See 1980 AACS, R 408.44. However, there is no accrued amount in the case in which defendants, such as these defendants, petition the bureau to reduce or stop compensation. As one commentator has explained:
An attorney is sometimes required to expend a lot of time and effort, and perhaps invest in substantial costs, for a case that does not lead to any recovery of accrued benefits. A petition to stop is a typical example of such a case. As discussed in §20.10 supra, when there is an order to pay continuing compensation benefits, an employer can challenge the continuing disability of the plaintiff by filing a petition to stop. This is often litigated in the same way as the worker’s original petition for hearing. The plaintiff’s attorney must meet with his or her client many times, take several medical depositions, and perhaps even schedule one or more physical examinations. Throughout this time, however, the defendant continues to pay *630benefits. When the case is over, therefore, there are no accrued benefits from which attorney fees can be paid, even if the plaintiff prevails. In Gross v Great Atlantic & Pacific Tea Co, 87 Mich App 448; 274 NW2d 817 (1978), the plaintiff sought payment for his attorney fees from the defendant employer. The court of appeals indicated that "the equities in this case are with [the] plaintiff,” yet ruled that it had no authority to require a defendant employer to pay the plaintiff’s attorney fee in such a case. Id. at 451; 274 NW2d at 819. Theoretically, the plaintiff’s attorney is entitled to recover 30 percent of the amount the worker received from the time the defendant attempted to terminate benefits until the case was concluded. The practical problem, however, is that most workers find it difficult to support themselves and their families even on the entire amount of benefits they receive. It would be extremely difficult for them to set aside 30 percent to pay their attorneys at some future date. In most such cases, the same attorney represented the worker in the original claim and received a substantial fee. Most plaintiffs’ attorneys simply feel that it "comes with the territory” to represent the same client in the subsequent litigation without the assurance of any reimbursement. [Welch, Worker’s Compensation in Michigan: Law & Practice, § 24.01, pp 347-348. Emphasis in the original.]
The lead opinion concludes "that plaintiff in this case should not be required to repay dependency benefits received prior to the date of this opinion . . . .” Opinion of Griffin, J., ante, p 604. However, the lead opinion does not foreclose the possibility that this Court, in future cases, will attempt to force previously paid benefits from *631injured workers. This apparently distinguishes Justice Brickley’s opinion which retains a blush of res judicata for benefits previously received. Furthermore, while the lead opinion suggests that either a change in law or the possibility that the subsequent petition would change only the amount of benefits, is the basis for its holding, Justice Brickley’s "disagreement does not involve the question whether an exception to res judicata should apply, but rather whether the application of the res judicata concept in cases arising out of income-maintenance systems such as workers’ compensation permits redetermination in light of an intervening change in the case law.” Concurring opinion of Brickley, J., ante, pp 608. While it is clear that the traditional rule of res judicata in workers’ compensation proceedings has been abandoned, absent a majority for the rationale for today’s result, it remains unclear whether the plurality’s rule will control in future litigation.