Introduction
Aspiring or experienced product managers (PMs) facing interviews with top tech companies such as FAANG can find them challenging. Not only do they require creativity and deep product insight, but also a systematic approach to problem-solving. A common analytical and estimation question might be: “Estimate the daily number of transactions in the US.” This post will explore how to approach such estimation questions utilizing structured frameworks and strategies.
Detailed Guide on Framework Application
Picking the Right Framework
For estimation questions, the Fermi Estimation method is highly recommended. Named after physicist Enrico Fermi, this technique involves breaking down large, complex problems into smaller, solvable components. It is particularly effective for high-magnitude estimation questions where the exact number is less important than understanding the scale of the number.
Step-by-Step Framework Application
1. Define the Parameters: Initially, determine what qualifies as a transaction. Assume it includes all transaction types like cash, credit/debit cards, online payments, and bank transfers.
2. Segment the Market: Divide the total transactions into manageable categories such as retail purchases, online shopping, bill payments, and others.
3. Estimate the Population and Usage: Start with the adult population of the US, which likely partakes in daily transactions. Assuming there are around 250 million adults, estimate how many transactions each adult could make in a day.
4. Factor in Businesses: Businesses also significantly contribute to the total daily transactions. Estimate how many active businesses there are and the average number of transactions they handle daily.
5. Gather Comparative Benchmarks: Use known data for validation, such as the daily transaction volume of significant payment networks like Visa.
6. Adjust for Outliers: Adjust your estimates to account for individuals who transact less frequently and businesses that transact more often.
7. Summarize Your Findings: Combine the estimates from every category to arrive at a total estimate of daily transactions.
Example with Framework
Considering the defined parameters and categories, if an average US adult makes about 3 transactions per day, this results in 750 million transactions from adults alone. Add to this an estimation of 30 million active businesses averaging 10 transactions each, contributing an additional 300 million transactions. Combining these figures, we achieve an approximate total of 1.05 billion transactions per day.
Facts Checks and Logic Validation
Always verify your assumptions using available data. For example, in 2019, the Federal Reserve noted approximately 174.2 billion transactions for that year in the US, averaging about 477 million daily. Though not encompassing every transaction type, this historical data supports the order of magnitude of your estimate and validates your reasoning process.
Effective Communication Tips
Articulate the logic behind each step of your estimation clearly. Acknowledge and justify your assumptions, and be prepared to discuss and defend your methodology. Display confidence, but also be open to feedback and alternative approaches that the interviewer may propose.
Conclusion
Addressing estimation questions effectively in PM interviews necessitates a balance of qualitative understanding and quantitative skill. Applying the Fermi Estimation method, carefully deconstructing the problem, logically supporting each step, and communicating your thought process clearly are all crucial. Regular practice with various estimation challenges will help hone your skills and boost your interview success potential at FAANG companies.