Here’s an easy way to prevent a discrimination claim: Offer everyone holding the same position the same opportunity for training. Otherwise, supervisors may play favorites, and that can end in litigation if the better-trained employees end up getting the promotions.
Recent case: Alison Terry sued over lost promotions while working as a seasonal life guard for the city of San Diego. She argued that almost all promotions went to male lifeguards. The city said it was because the men had more training.
Terry countered that only men were offered extra training and encouraged to take additional classes that made them more qualified.
The 9th Circuit Court of Appeals said that lack of opportunity was grounds for a trial because it could explain why so few women were promoted. (Terry v. City of San Diego, No. 09-55579, 9th Cir., 2010)