Introduction
Welcome to a preparing guide for FAANG Product Manager interviewees. It’s imperative to understand that PM interviews will often revolve around your analytical and estimation abilities. For those aiming to make a mark, it’s crucial to use structured frameworks when answering interview questions. Today, we will tackle the question: “How can you estimate the number of people going through an airport security scan every day?” This reflects a common type of estimation question you might encounter.
Detailed Guide on Framework Application
Choosing a Framework
For estimation questions, the logical framework to apply is the Fermi Estimation technique. This approach breaks down complex problems into smaller, more manageable chunks for which you can estimate values and then combine to get an approximate overall answer.
Step-by-Step Application of the Fermi Estimation
- Choose an Airport: Let’s consider Los Angeles International Airport (LAX), one of the busiest airports in the world.
- Identify Key Variables: Variables could include the number of flights per day, average passengers per flight, hours of operation, and throughput capacity of security lanes.
- Estimate Each Variable: Use public data, where available, or make educated guesses based on standard values. For example, LAX might handle ~1,500 flights daily, with an average of 150 passengers per flight.
- Calculate Based on Variables: Multiply the number of flights by the average passengers to estimate total daily passengers. Assume operational hours are 20 per day and consider peak times.
- Adjust for Repeat and Crew Passengers: Remember to adjust your numbers for crew members and connecting passengers who may not go through security at LAX.
- Combine Estimates: Multiply your estimate of single passenger security checks with the operational hours, and consider the number of security lanes to get a rough daily throughput.
Hypothetical Example
Imagine LAX has 1,500 flights a day, with 150 passengers on each, giving us 225,000 potential passengers. With the airport open 20 hours a day and assuming a security throughput rate of 3 passengers per minute per lane, and approximately 50 active lanes, we get 9,000 passengers processed per hour. So in a 20-hour window, theoretically, 180,000 passengers could be scanned. However, considering efficiency loss and downtime, we can adjust our estimation down by a certain percentage, say by 20%, leading us to a rough estimate of 144,000 passengers going through security scans each day at LAX.
Fact Checks and Approximations
Check aviation websites and airport reports for exact numbers of flights and traffic reports. Use logical assumptions and average values for other data that’s not readily available, always explaining your reasoning to the interviewer.
Effective Communication Tips
Clearly state your assumptions, breakdown the problem into small pieces, explain your thought process, stay calm, and be willing to discuss and adjust your hypothesis.
Conclusion
Using the Fermi Estimation technique, we have broken down a complex problem into manageable parts, made logical estimates, and combined them to answer the interview question. Remember, the key is not to find the exact number but to show your analytical skills and thought process. Practice this approach and refine your estimation skills to excel in your PM interviews.