This letter did not mention the alleged sexual harassment. Three weeks later she sent a second letter explaining that she had quit because of Slowik's behavior. While she was employed at Burlington, Ellerth did not inform anyone about Slowik's conduct, despite knowing that Burlington had a policy against sexual harassment. It is clear from the facts of each case that the supervisors themselves would probably be liable. The key question is whether or not these acts of the supervisors should be imputed to the employers, thus making the employers vicariously liable.
Vicarious liability is a concept of what is known as agency law.
It is important to note that this is indirect liability. The employer need not have done anything improper itself. It is also important to note that in some limited circumstances liability may be imputed, even when the employee in question acts outside the scope of his employment. After an involved discussion of the law of agency, the Court, in a joint ruling, applicable to each case, determined that sexual harassment by a supervisory employee is one of those limited instances when an employee's conduct will be imputed to the employer, even when that conduct is outside the scope of employment. When no tangible employment action is taken, a defending employer may raise an affirmative defense to liability or damages, subject to proof by a preponderance of the evidence.