In the 17th century fable The Monkey and the Cat by Jean de La Fontaine, a monkey convinces a cat to push roasting chestnuts from a fire, singing his paws in order to provide the monkey with a meal. Ever since, “cat’s paw” has referred to deriving benefit from the dirty work of others. In its 2011 Staub decision, the U.S. Supreme Court applied this principle to situations where an illegal employment decision is unwittingly made by a supervisor who is manipulated by the opinions or actions of a third party with discriminatory or retaliatory motives. Regardless of the deciding supervisor’s lack of illegal motivation, the employer can be found liable based on the cat’s paw theory.
 
After Staub, employers have considered how to counteract biases that may be present in evaluations relied upon by a decision-maker to determine wage increases, promotions, or even continuing employment. Some employers have tried to counteract this possibility through the use of employee evaluation processes that do not rely on one uninformed supervisor to make a final decision with regard to that employee. For example, before a final decision is made with regard to the evaluation (especially adverse decisions), human resources will separately review the situation with the decision-maker, particularly when the decision is based on the input of a single supervisor.
 
By using multiple layers of review, the employer can demonstrate that it would have made the same decision regardless of the input of an allegedly biased supervisor. This additional layer of review breaks the causal chain between the supposedly manipulative supervisor and the final evaluation and decision. Employers can devise multiple ways to break this chain, with the key being the ability to show that the final decision was not based on the input of one person.