Are you asking for technique for hiring processes or employee retention?
From observation, I see very fair hiring process in companies that treat employees as replaceable cogs that get trained, used and within a few years replaced. One place that I know which operate like that has equal hiring ratios, gender ratio of almost 50/50, pays exactly the same for both women and men, and are extremely unflexible in terms of work hours, task selection/satification and pay. As a result they also have a very high churn rate.