Chapter 1: Understanding Fermi Questions

Years ago, during my early interviews with consulting and banking firms for graduate roles, I frequently encountered Fermi questions.

What exactly are Fermi questions? Here are a few examples:

• How many $10 bills are currently in circulation in the United States?
• How many golf balls could fit inside a Boeing 777?
• What is the estimated number of piano tuners in Chicago?

Fermi questions require estimation for situations that can't be quantified accurately. They are named after the physicist Enrico Fermi, known for making estimations with minimal data. A notable instance was during the first atomic bomb test in New Mexico in 1945, when Fermi estimated the energy released by observing the movement of paper in the shock wave.

Despite their historical context, these questions remain prevalent in countless interviews today. The reason for their popularity eludes me, but it seems interviewers who favor them do so for personal enjoyment. Observationally, these interviewers are often men, typically with mathematical backgrounds.

They might ask these questions for several reasons:

• A preference for a less structured interview format.
• An interest in how candidates estimate without data.
• Enjoyment in witnessing candidates tackle essentially unsolvable questions.
• An inclination to showcase their own problem-solving methods, perhaps even to boost their ego if the candidate diverges from their approach.

Section 1.1: The Inappropriateness of Fermi Questions

Interview questions should always be relevant to the position. Can you think of a job that requires estimating the number of golf balls in a Boeing 777? Or gauging how many piano tuners exist in Chicago with no data?

In today’s world, candidates generally have access to three critical resources that are absent when responding to Fermi questions during interviews: data, computational tools, and time. Expecting candidates to solve these questions using mere mental arithmetic in a short timeframe is not only unkind but also reflects poorly on an organization’s values.

The consequences of this practice are severe; candidates may be rejected based on their inability to tackle a problem they will never encounter in their role, or because they approached it differently than the interviewer. This can harm diversity, fairness, and inclusivity in the hiring process, often leading to the hiring of more men, white individuals, and those who think similarly to the interviewer—detrimental outcomes for any organization.

Section 1.2: A Call to Action

If you are part of an organization that employs Fermi questions in interviews, or if you know someone who does, speak up. Advocate for questions that genuinely reflect the responsibilities of the job.

For interviewees facing a Fermi question, provide feedback to the organization. Mention the interviewer who posed the question, and ask whether they truly believe it relates to the job. Make it clear that such questions undermine their commitment to fairness and inclusivity.

Fermi questions remain overly common in job interviews, and it’s time to bring this practice to an end.

Chapter 2: Insights from Expert Opinions

This video, "Don't ask questions at the END of your interview. Do this instead!" offers alternative strategies for effectively engaging with interviewers.

In the video "Employers: Don't EVER Ask These Interview Questions," experts discuss the pitfalls of outdated interviewing techniques like Fermi questions, emphasizing the need for better practices.