The main legal thread which runs throughout the determination of the applicability of res judicata, inclusive of the adjunct principle of collateral estoppel, is the necessity of a fair opportunity to fully litigate and to be "heard" in the due process sense. Accordingly, an absolute due process prerequisite to the application of collateral estoppel is that the party asserting the preclusion must prove that the identical issue was actually litigated, directly determined, and essential to the judgment in the prior action.

(citations omitted). Therefore, the City must prove that the issues of race and sex discrimination were actually and directly at issue in the prior state proceedings, and that they were essential to the judgment of the state court against Cooper.

The record in this case reveals that the question of whether Cooper's discharge was the result of race or sex discrimination by the City was not actually or directly presented to or ruled upon by the OBES or the Common Pleas Court. The prior state proceedings instead addressed Cooper's entitlement to unemployment benefits. Ohio Rev.Code Sec. 4141.29(D)(2)(a) (Page 1980) provides that an individual is ineligible for benefits if he or she "has been discharged for just cause in connection with his [or her] work." In the present case, Cooper was denied benefits by the OBES because it found that her employer had "just cause" to discharge her. The determination of whether just cause exists focuses on the existence of fault on the part of the employee as a factor in the discharge. See Sellers v. Board of Review, Ohio Bureau of Employment Serv., 1 Ohio App. 3d 161, 164, 440 N.E.2d 550 (1981). Here, the OBES concluded that Cooper's discharge was justified by her infractions of the rules of her employer. On appeal, the Common Pleas Court held that the OBES determination was not "unlawful, unreasonable, or against the manifest weight of the evidence." Ohio Rev.Code Sec. 4141.28(O). The court rejected Cooper's arguments that her transgressions were insufficient to justify the discharge, and that the OBES hearing was unfair in that Cooper was unable to present her side of the case. The record is devoid of any consideration of race or sex discrimination, and such claims were beyond the scope of the administrative and state court actions.1 Under these circumstances, the courts of Ohio would hold that Cooper's discrimination claims are not barred by the prior state proceedings.

The City's reliance on Kremer v. Chemical Constr. Corp., 456 U.S. 461,102 S.Ct. 1883, 72 L. Ed. 2d 262 (1982), is misplaced. In that case, the question confronting the Supreme Court was whether to "give preclusive effect to a decision of a state court upholding a state administrative agency's rejection of an employment claim as meritless when the state court's decision would be res judicata in the State's own courts." 456 U.S. at 463, 102 S.Ct. at 1888. The Court held that the prior state proceedings barred the plaintiff's Title VII charges of discrimination. In Kremer, New York law clearly held that the judicially-affirmed determination of the New York State Division of Human Rights that plaintiff was not the victim of discrimination barred later suits based on the same grievance. Id. at 467, 102 S.Ct. at 1890 (quoting New York law). In this case, the prior state proceedings did not encompass the claims raised in the subsequent Title VII lawsuit, and the Ohio courts would not apply collateral estoppel.2

The City's reliance on Pullar v. UpJohn Health Care Serv., Inc., 21 Ohio App. 3d 288, 488 N.E.2d 486 (1984), is also unavailing. There the Cuyahoga County Court of Appeals held that a prior OBES decision that plaintiff had been terminated for just cause bars a later age discrimination action. The discrimination suit was based on an Ohio statute that prohibits discharging individuals between the ages of 40 and 70 "without just cause." 21 Ohio App. 3d at 290, 488 N.E.2d 486 (quoting Ohio Rev.Code Sec. 4101.17). Pullar is distinguishable from the present case, as the subsequent discrimination suit raised the same issue of just cause to discharge as had been addressed in the OBES proceedings. In this case, as previously stated, the prior OBES proceedings did not encompass the claims raised later in the discrimination action. Moreover, a number of decisions from the other Ohio courts indicate that collateral estoppel does not apply in circumstances similar to those in the present case. These courts have refused to give collateral estoppel effect to judicially-affirmed administrative decisions, holding that those decisions did not affect later proceedings addressing issues not directly raised in the first actions. See, e.g., Ohio Dept. of Mental Health, Cambridge Mental Health Center v. Hunt, No. CA-766 (Ohio Ct.App. Aug. 2, 1985); Pickaway County General Health Dist. v. Administrator, Ohio Bureau of Employment Serv., No. 84-CA-12 (Ohio Ct.App. July 1, 1985); Reed v. Dodge, No. E-84-41 (Ohio Ct.App. March 15, 1985).

The foregoing analysis reveals that the courts of Ohio would not preclude Cooper from asserting her discrimination claims because of the prior judicially-affirmed OBES proceedings. The district court's refusal to apply the doctrine of collateral estoppel is affirmed.

II. COOPER'S CLAIMS OF INTENTIONAL DISCRIMINATION

The City next challenges the district court's finding that plaintiff proved intentional discrimination, in violation of Title VII and Sec. 1981.3 The district court concluded that Cooper had established intentional discrimination under two theories: disparate treatment and retaliatory discharge. The City argues that the district court's conclusions on the issues are legally erroneous.

Section 703(a)(1) of Title VII, 42 U.S.C. Sec. 2000e-2(a)(1), generally prohibits race or sex discrimination in any employment decision. McDonnell Douglas Corp. v. Green, 411 U.S. 792, 796, 93 S. Ct. 1817, 1821, 36 L. Ed. 2d 668 (1973). A Title VII plaintiff bears the burden of proving that it is more probable than not that she was discriminated against on a proscribed basis. The district court correctly found that Cooper could establish a prima facie case of disparate treatment pursuant to McDonnell Douglas if she showed 1) that she was female and a member of a racial minority; 2) that she and a similarly situated white or male person received dissimilar treatment; and 3) that sufficient evidence exists from which the court can find a causal connection between race or sex and the alleged acts of the defendants.

The City contends that Cooper failed to establish a prima facie case, as she did not prove that she was treated differently than similarly situated white and male employees. It argues that the district court, in concluding that a prima facie case had been established, erroneously compared Cooper to employees who were not similarly situated. Specifically, the City objects to the district court's comparing of Cooper's record to those of Lawrence Sindalar and Ken Moss. The City points out that Sindalar was a permanent rather than a probationary employee during the relevant time period, and that Moss' probationary period occurred five years earlier under a different General Manager than that of Cooper.

A probationary period of employment permits a company to weed out or eliminate undesirable employees. See, e.g., Farmer v. Colorado and Southern R.R. Co., 723 F.2d 766, 767 (10th Cir.1983). The opportunity to dismiss more readily those new employees whose job performance is unsatisfactory is particularly important to NOMBL. As a common carrier, NOMBL has the duty of exercising the highest standard of care for the safety of its passengers. See, e.g., Mitchell v. Marker, 62 F. 139, 142-43 (6th Cir.1894); May Dept. Stores Co. v. McBride, 124 Ohio St. 264, 178 N.E. 12 (1931). Probationary bus drivers therefore do not stand on equal footing with permanent drivers, and cannot be considered to be similarly situated. See, e.g., McKenna v. Weinberger, 729 F.2d 783, 789 (D.C.Cir.1984).

The district court improperly compared the work records of Sindalar, a permanent employee who was not discharged, and Cooper, a probationary employee who was discharged. This error requires a remanding of this case to the district court. On remand, the district court shall make findings as to whether Cooper has established that she was treated differently than other NOMBL probationary employees.

The district court also compared Cooper to Ken Moss, who began his probationary year of employment in 1976 under General Manager Ernie Zoldesy, Ken Mues' predecessor. The City contends that it presented ample evidence at trial that Zoldesy did not possess the managerial skills of Mues. It concludes that any difference in the treatment received by Cooper and Moss can be explained by the change in managers. The district court refused to consider the change in management, finding it "entirely appropriate" to compare the treatment received by Cooper and Moss. Cooper v. City of North Olmsted, C82-3089, at 34 (N.D.Ohio Feb. 11, 1985). Although a change in managers is not a defense to claims of race or sex discrimination, it can suggest a basis other than race or sex for the difference in treatment received by two employees. See Tate v. Weyerhaeuser Co., 723 F.2d 598, 606 (8th Cir.1983), cert. denied, --- U.S. ----, 105 S. Ct. 160, 83 L. Ed. 2d 97 (1984). The district court therefore should have considered the management change in determining the probative value of the comparison between Cooper and Moss. On remand, the district court shall consider this factor in its analysis of Cooper's disparate treatment claim.

The City next argues that the district court erroneously conducted the analysis of discrimination claims set forth in Texas Dept. of Community Affairs v. Burdine, 450 U.S. 248, 101 S. Ct. 1089, 67 L. Ed. 2d 207 (1981). According to Burdine, the plaintiff must first establish a prima facie case of intentional discrimination, which the defendant can rebut by producing a legitimate, nondiscriminatory reason for the discharge. "The defendant need not persuade the court that it was actually motivated by the proffered reasons.... It is sufficient if the defendant's evidence raises a genuine issue of fact as to whether it discriminated against the plaintiff." 450 U.S. at 254-55, 101 S.Ct. at 1094 (citation and footnote omitted). If the defendant meets this burden of production, the plaintiff must then prove that defendant's asserted motive is pretextual. The need to prove pretext merges with the plaintiff's ultimate burden of persuading the court that she was the victim of intentional discrimination, a burden that the plaintiff retains at all times. Id. at 254-56, 101 S.Ct. at 1094-95.

In the present case, the City offered Cooper's numerous infractions of NOMBL rules, as recorded in the deficiency book, as its legitimate, nondiscriminatory reason for discharging her. Cooper then offered evidence that many of the deficiency book entries did not correspond to the facts of the situation, and that some of them were made in violation of company policy. The district court examined the deficiency book entries, one by one, and found that Cooper's version of the recorded events was credible. The court concluded that the vast majority of the deficiency book entries should not have been made, and that Cooper had therefore proved that the City's proffered reason for the discharge was a pretext.

The district court appears to have focused on whether or not the court believed Cooper's version of the facts surrounding the alleged infractions of NOMBL rules. In so doing, the district court overlooked the crucial inquiry in this case, which is whether the City intentionally discriminated against Cooper. The court should not put itself in a position of judging the correctness of the defendant's action in discharging the plaintiff. Instead, the court should look at whether the actions and the intentions of the defendant were pretextual or amounted to intentional discrimination. To determine the City's motivation in discharging Cooper, the district court must make specific factual findings on 1) whether the City relied on the deficiency book entries in discharging Cooper; and 2) if the City did so rely, whether that reliance was reasonable under the totality of the circumstances in this case. Therefore, this case must be remanded to the district court, with instructions to make these essential factual determinations.4

Section 704(a) of the Civil Rights Act of 1964, 42 U.S.C. Sec. 2000e-3(a), forbids discrimination against employees for attempting to protest or correct allegedly discriminatory conditions of employment. McDonnell Douglas, 411 U.S. at 796, 93 S.Ct. at 1821. To support a claim of retaliatory discharge, a plaintiff must prove: 1) that she engaged in activity protected by Title VII; 2) that she was the subject of adverse employment action; and 3) that there is a causal link between her protected activity and the adverse action of her employer. Jackson v. RKO Bottlers of Toledo, Inc., 743 F.2d 370, 375 (6th Cir.1984). The City contends that Cooper failed to establish a prima facie case of retaliatory discharge, as she did not prove a causal link between her filing of OCRC charges and her discharge four months later.

The district court found that Cooper filed discrimination charges with the OCRC on February 15, 1980, and that the City received a copy of the charges on February 25, 1980. The court stated that Cooper was then "immediately cited for myriad alleged violations of NOMBL rules," and that those citations culminated in Cooper's discharge. Cooper v. City of North Olsted, No. C82-3089, at 35-36. From this, the district court concluded that plaintiff established a prima facie case of retaliatory discharge.

The district court's factual findings do not support its conclusion that Cooper established a causal link between the OCRC complaint and her discharge. The mere fact that Cooper was discharged four months after filing a discrimination claim is insufficient to support an interference of retaliation. See, e.g., Brown v. ASD Computing Center, 519 F. Supp. 1096, 1116-17 (S.D.Ohio 1981), aff'd sub nom. Brown v. Mark, 709 F.2d 1499 (6th Cir.1983). The district court appears to have relied on the fact that Cooper was cited for rules violations six times in the seven month period preceding her OCRC complaint, and nine times in the four months following the complaint. The district court further noted that four of the pre-complaint citations were unjustified.5 The record in this case contains no evidence directly linking the nine citations at issue to Cooper's filing of the OCRC discrimination charges. While a disparity in the amount of disciplinary action may certainly be sufficient in appropriate cases to support an inference of retaliation, this is not such a case. Standing alone, the change in the number of deficiency book entries on which the City could reasonably rely, and Cooper's discharge four months later, do not establish a prima facie case of retaliatory discharge. The district court's finding on this issue is clearly erroneous, and must be reversed.6

The judgment of the district court denying collateral estoppel effect to the prior judicially-affirmed OBES proceedings is affirmed. The district court's finding of disparate treatment, in violation of 42 U.S.C. Secs. 1981, 2000e-2(a)(1), is vacated, and the case is remanded for further proceedings in conformance with this opinion. The finding of retaliatory discharge, in violation of 42 U.S.C. Secs. 1981, 2000-3(a), is reversed.