When deciding whom to promote, make sure you're using an impartial selection process to pick the best candidate. That's the only way to stay on safe legal ground if an employee you passed over for the slot sues you for discrimination.
The losing candidate would have a tough time proving that no reasonable person would have chosen the winner. Clearly demonstrating the winner's superior qualifications will sink a failure-to-promote case.
Best bet: Use this two-step selection process:
First, identify qualified internal candidates and advertise the post. Interview and select the best qualified, asking each one the same questions.
Next, double-check your choice by having an outside panel interview and rank the candidates. If the panel's selection matches the initial interviewers', a passed-over candidate would have a hard time arguing that he or she clearly was the superior choice.
Case in point: Ever Higgins vied with three others for a promotion to plant HR manager at Tyson Foods. When Higgins wasn't selected, she sued, alleging race discrimination.
Tyson insisted it had been impartial. It had asked every candidate the same questions, double-checked their work credentials and run the manager's selection by an outside panel of hiring consultants. Three panel members picked the same candidate for manager, while the fourth chose Higgins.
The 11th Circuit tossed out Higgins' case, saying she failed to show that "no reasonable person, exercising impartial judgment," would have picked someone else for the job. (Higgins v. Tyson Foods, No. 04-14749, 11th Cir., 2006)
Tip: For lower-level promotions, a second round of interviews may be overkill. Still, be prepared to show the loser wasn't clearly the superior candidate.