The Interview Question as Development Tool

Many top companies use estimation questions in job interviews to judge the intelligence and flexibility of their applicants. Microsoft was one of the first and probably has the most famous set of questions. Questions like “How many golf balls would it take to circle the Earth at the equator?” (Approximately one billion). Or, “How would you go about estimating the number of gas stations in the United States?” (The question fundamentally asks for a methodology and not an answer - - be sure and listen to the question. I mistakenly ask this one time and after 20 minutes into a floundering explanation that should have taken two minutes, I decided a far more pleasurable experience would involve being handcuffed to a radiator in Beirut by Hezbollah).

Many of these types of questions are contained in a book by Lawrence Weinstein and John Adams entitled Guesstimation (2008). Several of the questions are silly while others make one pause and appreciate the creativity of the human spirit (“How many people in the world are picking their nose right now?” - - I will not bore you with the calculations, but in 2008 the answer was approximately 10 million - - page 78). I think there are two things people can take away from these types of questions and the methodology/exercises outlined in the book - - (1) an understanding of the meaning of large numbers, and (2) an ability to make rough, common sense, estimates starting from just a few basic facts.

Google has its own spin on the interview question that is more reflective and open ended - - a deeper examination of potential candidates. I really like their “Tell me a joke” question (Freud would probably have a field day with those individuals that cannot come up with a joke). Their “Explain something technical to me - - you pick the topic” is not only a great interview question, it is also a really good learning exercise and development tool. Having engineers explain something technical (especially to the non-technical or to individuals and groups outside their particular discipline) requires them to rely on metaphors and analogies to express themselves. This mix of intellects, experiences, and interests in an audience forces a distinct type of interaction that produces the need for a conversation of abstraction. Abstractive thinking is a focus on the core concepts - - reducing the information and ideas down to its most relevant structure and form. These abstractions are essential for problem solving, as they encourage engineers to reconsider their basic assumptions and ideas. Having to explain the problem or technical application to someone else forces them to think, if only for a moment, like an intellectual on the margins, filled with self-skepticism. Is this correct - - have I really thought this completely through?

This is why different types of people are so useful in the audience - - they help to shake engineers out of their cognitive boxes. Google understand this - - it is why they ask the question. The engineer trying to describe his or her approach, getting a little defensive, and then getting a quizzical look on his or her face - - finally seeing what was important. Seeing what was missed. Seeing what was vague, dull, and muddy. Seeing new paths and connections to old assumptions and methodologies.

Be prepared to “Explain something technical - - you pick the topic” not only in the context of an interview but also in the context of developing better problem solving and communications skills.