How do you keep your most valued employees? Ask the ones who are leaving.

With turnover costing companies more money than ever, the exit interview is becoming an increasingly important tool, according to CFO magazine. The information you get from exiting employees can help you improve operations and employee relations … and keep staff happy in the process.

But crafting a helpful exit interview takes skill, and the article offers a list of open-ended questions that might draw useful insights from departing employees.

What’s the most useful question that you ask during an exit interview?