Organizations employ a variety of methods to measure and track employee engagement, but probably none as surprising as this: In a recent survey by the Society for Human Resource Management (SHRM) and Globoforce, an employee-recognition-services firm, 65 percent of firms reported using exit interviews as one of the ways they measure engagement.

“It’s like closing the barn after the horse is already out,” said Kevin Kruse, author of We: How to Increase Performance and Profits Through Full Engagement, in reaction to the finding.

“It’s after the fact, and engagement is something that happens when they’re employed,” added Jim Harter, chief scientist of workplace management and well-being at performance management firm Gallup.

Even Derek Irvine, vice president of client strategy and consulting with Globoforce, was taken aback by exit interviews’ prominence as part of the engagement measurement process.

The bottom line, all three said, is that the exit interview is not the best place to have a comprehensive engagement conversation with an employee. Some even questioned the validity of an exit interview altogether.

Yet the three did agree, after some thought, that if an exit interview is going to be used to track engagement, there are some instances where the data could be used to help firms add value.

Harter said the exit interview might become a principal engagement measurement tool if a firm is experiencing a rash of employee defections. “If you’re bleeding, you’ve got to get the stitches out and fix it if you’ve got a deep cut,” he said.

In this case, the exit interview becomes especially important, since HR managers need to figure out what to change in the short term to boost retention and get a gauge on engagement.

“Maybe they’ve lost some of their best performers,” Harter said. “[The exit interview] is more of a short-term fix from my perspective: ‘Let’s understand what we need to do differently right now.’”

Exit interviews can also bring forth surprising candor on engagement-related subjects from departing employees, Kruse said.

“Even if you get seven out of 10 leaving that are just going to give you the party line, maybe three are going to give you good data,” Kruse said.

It’s best to conduct anonymous surveys following an employee’s departure from a company maybe three or six months after they've left.

“Broadly speaking, you could learn something in an exit interview that could inform you about how to improve benefits, culture or improve a bad boss … and then those things could lead to improved engagement,” Kruse said.

Globoforce’s Irvine agreed: “You do catch an employee at a very particular time in their relationship with the company where there is a very candid and frank discussion.”

That said, employers shouldn’t count on employee candor too often during exit interviews -- because many are afraid of being brutally honest.

“It helps the company," Kruse said, referring to employees' candor during the exit interview. "It doesn’t help them.”

Frank Kalman is an associate editor of Talent Management magazine. He can be reached at fkalman@talentmgt.com.