When it comes to measuring employee engagement, there’s an oft-overlooked method — one that isn’t traditionally woven into the formal HR process — that some engagement specialists say might be the most effective of all: the stay interview.

Unlike the exit interview, where HR managers gain insights into employee sentiment just before they walk out the door, and the performance review, where managers assess employees’ performance for the year, the stay interview asks the question most managers yearn to ask their top talent: What could we do to make you stay?

“The ultimate goal of the stay interview is to stay in someone’s head and make sure we retain them,” said Kevin Kruse, author of WE: How to Increase Performance and Profits Through Full Engagement.

The stay interview is perhaps a manager’s most honest grip on engagement, according to Kruse. It’s a one-on-one meeting with a front-line manager and a direct report to gain insight on that employee’s perspective on the organization’s key engagement drivers, and to learn which of those drivers need fixing to retain top talent.

Kruse said stay interviews work best when they happen at least once or twice a year.

The stay interview is also not typically owned by the HR manager. If a manager feels that his or her relationship with an employee is particularly trustworthy, the stay interview might be more effective outside of the office — say at a coffee shop or over lunch, Kruse said.

A successful stay interview, however, isn’t as simple as just asking the question: “What could we do to make you stay?” HR managers need to train leaders to ask questions that help drive understanding on employee feelings about the key areas of engagement — company culture, communication, growth and recognition.

“It’s less about, ‘Are you going to leave?’ and more about, ‘How are you feeling about the things that would make them [want to] jump on Monster.com,’” Kruse said.

Managers should exercise caution in how stay interview questions are framed. For example, when asking employees about their feelings about communication, it would be best to refrain from asking blunt questions such as: “Do you think communication is going well here?”