What makes an employee a key employee? We can figure this out by asking the right questions: how replaceable are their skills, and how likely are they to leave?
Once we know how are key employees are, then what? Throwing more money at the problem doesn’t usually work, because money isn’t the problem. Retention is about more than money. At least more money doesn’t always do the trick.
What does the trick? “Praise from one’s manager, attention from leaders, frequent promotions, opportunities to lead projects, and chances to join fast-track management programs are often more effective than cash.”
Leadership, and opportunities to lead.