This case presents for our consideration circumstances surrounding a SERB decision to dismiss a ULP charge as untimely filed, without issuing a complaint. It does not involve a question of probable cause. On the precise facts of this case, because SERB did not make a full analysis of the issue of timeliness, we reverse the decision of the court of *151appeals denying appellant’s request for a writ of mandamus, grant a limited writ, and return this cause to SERB for further proceedings.
In order for a writ of mandamus to issue a relator must demonstrate (1) that he or she has a clear legal right to the relief prayed for, (2) that respondents are under a corresponding clear legal duty to perform the requested acts, and (3) that relator has no plain and adequate legal remedy. State, ex rel. Berger, v. McMonagle (1983), 6 Ohio St.3d 28, 29, 6 OBR 50, 50-51, 451 N.E.2d 225, 226-227; State, ex rel. Westchester Estates, Inc., v. Bacon (1980), 61 Ohio St.2d 42,15 O.O.3d 53, 399 N.E.2d 81, paragraph one of the syllabus.
We initially note that generally this court will not review a decision of SERB not to issue a complaint based on a ULP charge. That conclusion is consistent with our recent decision in Ohio Assn. of Pub. School Emp., Chapter 643, AFSCME, AFL-CIO v. Dayton City School Dist. Bd. of Edn. (1991), 59 Ohio St.3d 159, 572 N.E.2d 80, in which we held in the syllabus that “[a] decision by the State Employment Relations Board whether or not to issue a complaint in an unfair labor practice case is not reviewable pursuant to R.C. Chapter 119 or R.C. 4117.02(M) and 4117.13(D).” Because there was no direct right of appeal in the situation before us,2 the third requirement for mandamus is present in this case, in that appellant has no adequate legal remedy available.
We now proceed to consider whether the first two requirements for mandamus are met under the circumstances of this case. Because appellant’s right to the relief requested correlates directly to SERB’S duty to act, we consider both requirements together.
In finding that the ULP charge was not timely filed, SERB ruled that the ninety-day limit contained in R.C. 4117.12(B)3 and Ohio Adm.Code 4117-7-01(A)4 was not met under the circumstances of this case. In reaching this *152result, SERB gave no reasons for its conclusion, but summarily dismissed the ULP charge.5
This court normally accords great deference to a decision SERB has made on a particular issue. “It was clearly the intention of the General Assembly to vest SERB with broad authority to administer and enforce R.C. Chapter 4117. * * * This authority must necessarily include the power to interpret the Act to achieve its purposes.” Lorain City Bd. of Edn. v. State Emp. Relations Bd. (1988), 40 Ohio St.3d 257, 260, 533 N.E.2d 264, 267. Although we do not often readily question a decision SERB has made, our willingness to defer to SERB is not unlimited. When, as here, a genuine controversy exists regarding when a ULP “occurs,” SERB should be required to give some explanation of its finding of untimeliness.6
Because SERB summarily dismissed this ULP charge, there is no way for us to discern whether SERB considered all the facts and circumstances of this case in reaching its decision on the timeliness of the ULP charge. The parties were engrossed in negotiations at the bargaining table on an initial labor agreement while the ninety-day period for the filing of the ULP charge was running. Thus, there is some question whether an approach allowing for some type of tolling of the ninety-day time period would be appropriate under the circumstances of this case. We do not imply that such a principle should be employed. Rather, we simply observe that the record is insufficient to allow us to determine whether SERB acted arbitrarily.
In addition, the record reveals that prior to the employer’s agreement to abide by SERB’S (and ultimately the courts’) resolution of the merits of the ULP charge, the employer had argued to SERB that all the ULP charges were untimely filed. Appellant argues that the employer should have been es-*153topped from asserting timeliness as a defense. We do not presume to tell SERB how to deal with that argument. However, we do point out that while the ninety-day time period was running, the parties are presumed to have been engaging in good faith negotiations.
Appellant also argues that the employer here was under a continuing duty to negotiate and bargain over the sign-in and time clock procedure with appellant, that each refusal to bargain over the procedure was a separate ULP, and that several refusals occurred within ninety days of the ULP charge being filed, making the original ULP charge timely. See, e.g., NLRB v. Basic Wire Products, Inc. (C.A.6, 1975), 516 F.2d 261, 268. Appellant further asserts that there was no reason for it to file a new ULP charge, specifically over the employer’s failure to bargain, because the parties had already agreed to have SERB resolve the first ULP charge, which was to decide the appropriateness of the time clock and sign-in procedure. We neither accept nor reject appellant’s reasoning.
There are many factors present in this case — i.e., the ongoing negotiations involving the time clock and sign-in procedure, the employer’s statement that it would abide by SERB’S decision on the ULP charge filed in this matter, and appellant’s contention that the employer committed more than one ULP involving this issue — which have been left unresolved. Not granting the writ in this case would leave too many unanswered questions relating to these matters. We do not now decide whether SERB acted within the bounds of its discretion. That SERB may have acted appropriately in ruling the way that it did is irrelevant to our result; the state of the record in this case forces us to assume too much. The record before us, and in particular the notice of dismissal entered by SERB, is totally inadequate. Thus, we find that the first two requirements for mandamus are met in the precise circumstances presented by this case.
We narrowly hold, in the circumstances of this case, that SERB erred by failing to make a complete examination and determination of the timeliness issue. Therefore, we return this cause to SERB and issue a limited writ directing it to consider all the facts and circumstances of this case relevant to the question of timeliness, and to issue some explanation setting forth its reasoning.
Judgment reversed and limited writ allowed.
Sweeney, Douglas and H. Brown, JJ., concur. Moyer, C.J., Holmes and Wright JJ., dissent.. In its unsuccessful attempt to directly appeal SERB’S decision underlying this action, appellant contended that there is a fundamental difference between a situation in which SERB declines to issue a complaint because it finds no probable cause, and a situation in which SERB dismisses a complaint for untimeliness, without deciding whether there is probable cause. We agree that there is a significant conceptual difference between the two situations. It would appear, however, that the General Assembly has chosen not to provide a right of review in either circumstance. This question is conceded for purposes of this mandamus appeal.
. R.C. 4117.12(B) reads, in pertinent part:
« * * * ipjjg jj0arj may not issue a notice of hearing based upon any unfair labor practice occurring more than ninety days prior to the filing of the charge with the board * *
. Ohio Adm.Code 4117-7-01(A) reads, in pertinent part:
*152“A charge that an unfair labor practice has been or is being committed may be filed by any person. Such charge shall be filed with the board within ninety days after the alleged unfair labor practice was committed. * * * ”
. The entire text of SERB’S order of dismissal in this case (SERB Case No. 86-ULP-1-0016), issued December 4, 1986, reads:
“The Ohio Association of Public School Employees/American Federation of State, County and Municipal Employees, AFL-CIO (Charging Party) has filed an unfair labor practice charge against the Lorain County Board of Mental Retardation and Developmental Disabilities (Charged Party). The Charged Party alleged that the charge was untimely filed. The investigation revealed that the allegations giving rise to the charge occurred more than ninety (90) days prior to the filing of the charge with the Board. Pursuant to Ohio Revised Code Section 4117.12 and Ohio Administrative Code Rule 4117-7-01(A), the charge is dismissed.
“It is so directed.”
. The meaning of the word “occurring” is not set forth in the statute. As is true with many of the terms in R.C. Chapter 4117, SERB, in the sound exercise of its discretion, must define and interpret the term on a case-by-case basis.