(dissenting.) In Hartford Elevator, Inc. v. Lauer, 94 Wis. 2d 571, 586a-87, 289 N.W.2d 280 (1980), this court rejected the per se rule that once an employer proves disloyalty by an employee, the employer is automatically entitled to recover all compensation paid to the employee during the period of disloyalty. Instead, the court stated the following:
“The burden of proof to establish a right of the employer to recover compensation paid to the employee as a result of the employee’s breach of duty owed to the employer is upon the employer. The burden to go forward with evidence to establish mitigating circumstances which would limit the employer’s recovery is upon the employee.” Id. at 587. (Emphasis added.)
In my view, the majority opinion misapplies the Hartford Elevator burden of proof rule and its reasoning at times seems to approach a form of a per se rule of recovery. This is evident when the court states:
“We believe the very nature of the conflict of interest involved here leads to the conclusion that the disloyalty affected job performance and that MPC did not receive full value for the compensation paid Burg as manager of the molding department.” Supra at 9.
This statement contradicts the Hartford Elevator rule reaffirmed by the majority that it is the employer that has *17the burden of persuasion that full value was not received for compensation.
The majority states that the evidence, although partly disputed, was sufficient for the employer to meet its burden of proof as required by Hartford Elevator. A closer examination of the majority’s analysis, however, reveals that the majority is actually second-guessing the factual findings of the trial court.
Hartford Elevator requires that the employer must initially prove that the value of a disloyal employee’s services was less than that paid to him. Only when that burden is met does the employee have any burden to come forward with proof of mitigating circumstances in an effort to limit the employer’s recovery. The majority now places on the employee the burden to come forward with evidence once the employer establishes a prima facie case. That order of production of evidence is not set forth in Hartford Elevator.
The evidence brought forward by Burg at trial sought to demonstrate that his disloyalty had no bearing on the quality of his job performance. It was not offered as mitigating evidence as the majority labels it. It was simply evidence presented to dispute the contentions of a party opponent who ultimately bore the burden of persuasion on a particular issue.
The majority concludes that MPC met its burden to establish a prima facie case. The term prima facie case is generally thought to mean that the proponent has produced enough evidence to get to the trier of fact.1 I *18agree that MPC did come forward with sufficient evidence to properly claim that the trier of fact be allowed to consider the case. However, with the judge acting as the trier of fact, he concluded that the burden of persuasion which is on MPC was not satisfied. This court should defer to those findings. The majority’s discussion of the litany of several areas where the trial court found potential opportunities for lessening the value of Burg’s services to the employer is merely a recitation of where the trial court looked for proof in the record and found none favoring the employer.
The trial court held that MPC failed to sustain its burden of persuasion to enable recovery of Burg’s salary, since the evidence consisted only of “suspicions and possibilities, unsupported by probative credible evidence.” The majority contradicts this finding when it states that “Burg intentionally did not maximize production.” Burg-may have performed his job inadequately which ultimately led to his dismissal, but the trial court found only a paucity of causal evidence that the inadequate performance was directly related to his disloyalty.
The majority points to no evidence in the record to support its contention that “Burg’s failure to maintain the highest production possible in the molding department in order to serve his own interest clearly caused ‘loss, expenses and inconvenience’ to the employer.” Supra at 13. Rather, the majority, without seeing or hearing the witnesses, finds the weight of the employer’s evidence to be convincing, while the trial court found it to raise nothing but suspicion. Assessing the credibility of witnesses is not a function of this court.
In addition, there is a basic inconsistency in the majority’s opinion. The majority believes that MPC did sustain its burden to establish a prima facie case, yet it remands the case to the trial court because the issue of Burg’s compensation was not “squarely and completely *19tried.” I do not understand how the majority can conclude that a party met its burden to establish a prima facie case regarding an issue that was not adequately tried. In my view, the issue was tried. The majority admits the issue was raised in the pleadings. The employer believed the issue was tried since it was MPC that asked the trial court for a specific determination relating to Burg's entitlement to his salary. Moreover, the trial judge referred to the Hartford Elevator decision in his supplemental decision and properly applied his findings of fact to the Hartford Elevator rule.
I dissent and would affirm the court of appeals in all respects.
I am authorized to state that JUSTICE ABRAHAM-SON joins in this dissenting opinion.
Wigmore notes that “prima facie case” is often used in two senses. First, as stated above, it means that the proponent has come forward with sufficient evidence to go to the jury. It also sometimes means that the proponent has produced sufficient evidence to require a ruling in his favor should the opponent offer no evidence. 9 Wigmore, Evidence, sec. 2494 (Chadbourn rev. 1981). Because of this ambiguity, the majority’s use of the term “prima facie case” in explaining the proper burden of proof unnecessarily confuses the issue in this case.