I can remember going on interviews when I was an MBA student at Harvard from 1993-1995. Certain firms, particularly in the consulting industry, used to love using brainteasers as questions during interviews (along with the usual case interview methodology). My first experience with such a brainteaser was the following question: How many gas stations are there in the United States? The questions allegedly helped the interviewer understand your thought process and your approach to solving problems. Google, of course, became famous for using such brainteasers often during their job interviews. One of my former students was asked at a Google interview: "How many golf balls can you fit in this room?"
Now, we hear from a senior executive at Google that such questions did not predict effectiveness on the job. Here's an excerpt from an interview that the New York Times' Adam Bryant conducted with Laszlo Bock, senior vice president of people operations at Google:
"On the hiring side, we found that brainteasers are a complete waste of time. How many golf balls can you fit into an airplane? How many gas stations in Manhattan? A complete waste of time. They don’t predict anything. They serve primarily to make the interviewer feel smart. Instead, what works well are structured behavioral interviews, where you have a consistent rubric for how you assess people, rather than having each interviewer just make stuff up. Behavioral interviewing also works — where you’re not giving someone a hypothetical, but you’re starting with a question like, “Give me an example of a time when you solved an analytically difficult problem.” The interesting thing about the behavioral interview is that when you ask somebody to speak to their own experience, and you drill into that, you get two kinds of information. One is you get to see how they actually interacted in a real-world situation, and the valuable “meta” information you get about the candidate is a sense of what they consider to be difficult."
I wonder how other firms feel about these types of brainteasers. Will Google start a trend? Will other firms finally ditch these silly questions? I do think that Google's Laszlo Bok is correct - many interviewers are probably more interested in looking smart when they ask these questions, as opposed to truly learning something valuable. One must also wonder if there's not some element of this line of thought: "I went through this crucible; you should have to do so as well. Let's see how you fare." I'm sure some interviewers think this way when they consider asking one of these brainteasers.