Some companies, when you resign, have a human resources staffer conduct an exit interview. At others, they buy you a cake. At

Microsoft

(MSFT) - Get Report

, well, they don't miss the opportunity to gather just a little more data about the company.

That's what Howard Greenstein found out in January, nine months after he left his job as a Microsoft technology evangelist. Greenstein, now doing business development for presentation technology firm

Sorceron

, got a call out of the blue from the

Gallup Organization

-- you know, the same folks who found that 74% of Americans have a favorable opinion of

President Reagan

on his 90th birthday. But instead of asking Greenstein about

President Bush's

performance or

President Clinton's

pardons, Gallup asked his opinions of Microsoft, why he left, and, curiously enough, his willingness to work for the company part time in the future.

Microsoft confirms that for several years now it has retained Gallup to survey as many ex-Microsofties as possible, as a supplement to the usual exit interview departing employees undergo. By checking in with those departees a few months later, Microsoft gets access to people's thoughtful reflections about their time at the company, says Liz King, general manager in human resources for the company. "That's very useful learning for us -- about the employee experience, and how we can continually improve that," she says.

The company is

not

, however, trying to recruit part-time help, she says. That line of questioning, she says, is a morale barometer and general "input data" for considering "alternative work scenarios."

Greenstein, who departed on good terms and remains a Microsoft shareholder, says he was happy to give Microsoft feedback in the hopes that they'll use it to fine-tune employee retention. "It seems to me a good idea to keep employees," he says, "because it's always harder to find new ones."

The Gallup poll is just another example of how Microsoft, a company with a $345 billion market capitalization, didn't get there by accident. This is a company that doesn't like to leave things to chance -- something to keep in mind the next time you think the company will be buffeted by forces beyond its control.