Market Sizing Quant Interview Guide
Market sizing quant interview guide for defining scope, decomposing demand, estimating ranges, multiplying drivers, and checking scale.
Candidates seeing open-ended sizing and demand estimation questions.
Define the market first
Market sizing starts by naming geography, time period, customer type, and unit of measurement. A vague market definition produces a vague estimate.
Break demand into drivers
Use population, adoption rate, frequency, units per use, and price or volume where relevant. Keep drivers simple enough to explain aloud.
Concrete example
For annual gym visits in a city, estimate population, share with gym access, visits per member per week, and weeks per year. Multiply, then sanity-check the daily visit count.
Use ranges for uncertain drivers
If adoption could be 10 to 20 percent, carry that range through the estimate. A range is often more honest than a single fake-precise number.
Common mistakes
Candidates often start multiplying before defining the unit. Decide whether the answer is users, dollars, transactions, units, or time before building the estimate.
Practice the pattern
Use the LeetQuidity curriculum and calibration to turn this topic into a focused practice plan.