The "honest belief rule" is one of most effective shields available to employers in discrimination cases:
As long as an employer has an honest belief in its proffered nondiscriminatory reason for discharging an employee, the employee cannot establish that the reason was pretextual simply because it is ultimately shown to be incorrect. An employer has an honest belief in its reason for discharging an employee where the employer reasonably relied on the particularized facts that were before it at the time the decision was made.
To be effective, however, an employer must harness its "honest belief" properly. Consider Brooks v. Davey Tree Expert Co. (4/17/12), in which the 6th Circuit determined that an employer was not entitled to argue its honest belief in defense of an age discrimination claim.
According to the 6th Circuit in Brooks, the honest belief rule has limits:
[W]e do not require that the decisional process used by the employer be optimal or that it left no stone unturned. Rather, the key inquiry is whether the employer made a reasonably informed and considered decision before taking an "adverse employment action." Although we will not "micro-manage the process used by employers in making their employment decisions," we also will not "blindly assume that an employer's description of its reasons is honest."
In Brooks, the 6th Circuit concluded that the employer was not entitled to the benefit of the honest belief rule, because it could not "point to specific facts that it had at the time the decision was made which would justify its belief in the proffered reason."
What's the lesson for employers? If you want to be able to argue that your honest belief justifies your decision, you better be able to support your claim. Contemporaneously-made documentation, coupled with corroborating evidence, is best. As if you need another reason document, document, and document some more?