If you want to improve at engaging and retaining key employees, there's one simple step you can take. And now--the season of annual employee reviews and year-end recognition--is the perfect time to tweak your process for keeping your best and brightest people

This one step is known as a "stay" interview. Dr. John Sullivan, an HR thought leader and former chief talent officer for Agilent Technologies, has recommended stay interviews for more than 20 years.

How to Pull Off a Perfect Stay Interview

A “stay" interview, writes Sullivan on TLNT, is a one-on-one interview between a manager and a valued employee. Its aim, quite simply, is to learn what makes employees want to keep working for you. Likewise, it's designed to elicit what might make key employees want to leave. Conduct enough stay interviews, and you might find  your employees are citing the same reasons for staying (or wanting to go).

Sullivan suggests holding interviews once a year, during a slow business period. Don't space out the interviews, either. Conduct all of them (with all your key employees) within weeks of each other. That way, you can take what you've learned and promptly implement around that information. For new hires, conducting the interviews at four and eight months is acceptable. 

Start the interview. How do you initiate a stay interview with a key employee? Say something like this: "Thanks for taking the time to have this discussion. As one of our key employees, I want to informally pose some simple questions that can help me to understand the factors that cause you to enjoy and stay in your current role," writes Sullivan.

Learn why they stay. One method is to deploy what Sullivan calls the "best work of your life" question. Specifically, ask your employees: "Can you list for me the factors that could contribute to your doing the best work of your life?" Sullivan notes that this is the No. 1 retention factor for top performers. 

Learn why they leave. Ask about recent frustrations. Sullivan's questions include: "Think back to a time in the last 12 months when you have been at least slightly frustrated or anxious about your current role. Can you list for me the frustration factor or factors that most contributed to that anxiety? Can you also help me understand what eventually happened to lower that frustration level?"

Those are just three of the 20 questions Sullivan says you should consider asking in stay interviews. Ask them, and you'll be well on your way to improving engagement and retention. And remember: You're taking a big step, just by periodically asking your people if they're happy. "Most employees," writes Sullivan, "are excited simply by the fact that the organization is concerned about their future and that their manager took the time to consult with them."