Q. What else has Google done in this field?

A. I have to preface the answer by saying that when we look at any data related to our people, we treat the data with great respect. Typically, we give people an option to participate in anything either confidentially or anonymously. The lesson for anyone looking at this space is that you need to construct this really powerful tent of trust in the people gathering the data and how they use it.

We’ve done some interesting things to figure out how many job candidates we should be interviewing for each position, who are better interviewers than others and what kind of attributes tend to predict success at Google. On the leadership side, we’re looking at what makes people successful leaders and how can we cultivate that.

We’re also observing people working together in different groups and have found that the average team size of any group at Google is about six people. So we’re trying to figure out which teams perform well and which don’t. Is it because of the type of people? Is it because of the number of people? Is it because of how they work together? Is there something in the dynamic? We don’t know what we’re going to discover.

Q. Other insights from the studies you’ve already done?

A. 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.