Even smart people can get tripped up on personnel decisions.  Harvard, for example, ran into this problem in Pierce v. President and Fellows of Harvard College

That case involves an African-American university police officer claiming race discrimination and retaliation in the denial of three promotions and being placed on foot duty.  The court threw out the claims as to one of the promotions and the foot duty assignment, but found that there was enough evidence to support his claims as to two of the promotions to send it to trial.

Specifically, the court found “puzzling” and “inconsistent” Harvard’s explanations as to one of the promotions – that the promotion was cancelled by the chief of the university police department because a member of the interview panel leaked interview questions to one of the candidates, that there may have been sex discrimination because a highly-qualified female was not advanced in the process, and that a new development project might change the department’s staffing needs.  The court noted the inconsistency in the chief’s explanation of finding the leak to be so problematic that the promotion had to be cancelled, but not taking any disciplinary action against those involved in the leak.  As to the sex discrimination, a female panel member said that she saw no improprieties in the process.  And with regard to the staffing needs, Harvard failed to explain how or why the project would affect staffing.

As for the second promotion, the Court found troubling evidence that suggested the successful Caucasian candidate had been preselected for the position and that the selection process had been “exceptionally abbreviated,” with interviews lasting only 10 minutes each and taking place in the course of a single day.  The typical process takes at least one week, according to six witnesses.  The officer also offered evidence that his managers’ attitudes towards him changed after he complained about possible discrimination, and that he was targeted for an extended disciplinary investigation.  In addition, there was evidence that the departmental managers had retaliated against other employees, including similar changes in attitude, who had either complained about department management or supported complainants.

There are a number of lessons here for employers.  First, don’t offer inconsistent or changing explanations for an employment decision.  Second, make sure your explanation makes sense.  Third, don’t deviate from normal processes unless you have a really good reason for doing so (and make sure you can prove that reason).  Fourth, make sure you continue to interact with complaining employees in the same professional manner that you interact with other employees, and don’t assign them suddenly to less favorable work or shifts.