Google’s growth is staggering even by Silicon Valley standards. It is constantly leasing new buildings for its overflowing campus here and opening offices around the world.

Google has doubled the number of employees in each of the last three years. Even though the company now has about 10,000 employees, Mr. Bock says he sees no reason the company will not double again in size this year. That would increase the number of hires to about 200 a week.

As a result, Mr. Bock, who joined Google from General Electric last spring, has been trying to make the company’s rigorous screening process more efficient. Until now, head hunters said, Google largely turned up its nose at engineers who had less than a 3.7 grade-point average. (Those who wanted to sell ads could get by with a 3.0 average, head hunters said.) And it often would take two months to consider candidates, submitting them to more than half a dozen interviews.

Unfortunately, most of the academic research suggests that the factors Google has put the most weight on — grades and interviews — are not an especially reliable way of hiring good people.

“Interviews are a terrible predictor of performance,” Mr. Bock said.

Mr. Bock said that he wanted the company’s human resources department to bring the iconoclastic style as its Web site developers to the normally routine function of interviewing job candidates. “The level of questioning assumptions is uniquely Googly,” Mr. Bock said.

So Google set out to find out if there were any bits of life experience or personality it could use to spot future stars.

Last summer, Google asked every employee who had been working at the company for at least five months to fill out a 300-question survey.