Ironically, according Google's former head of HR, Laszlo Bock, their system of technical interviews with brainteasers not only was not efficient, it didn't perf

Ironically, according Google's former head of HR, Laszlo Bock, their system of technical interviews with brainteasers not only was not efficient, it didn't perform any better than random chance. He said that they conducted a pretty large study of the correlation between interview performance and job performance and found no correlation whatsoever. They would have done just as well picking names out of a hat. As a result, he pushed them to move more in the direction of "behavioral interviewing," asking people, for example, to describe difficult problems and how they had worked to solve them. That way you at least learn a little something about how the candidate thinks and about their style of communicating with a potential colleague about technical problems. If I recall correctly, the only formal process that has been shown to actually predict job performance well is standardized testing of job-relevant skills. Maybe companies should spend more effort on identifying the more important job-relevant skills and work with testing professionals to come up with appropriate tests? Then they could save interviews for finding out which of the top performers seem like they're going to be pleasant to work with.