Quantitative
Top-down sizing
Start from a big total and narrow it down.
Facts checked against sources onWhat does Top-down sizing mean?
Top-down sizing begins with a large known number, like a country's population, and narrows it step by step with fractions until you reach the quantity you want.
Example
For example: population, then the share who are adults, then the share who own a car, and so on.
Where does it come up in case interview prep?
- Cracking any estimation promptLesson in Guesstimates and market sizing
- Real growth, people and incomeLesson in Markets and economies: the world a case lives in
- How to use a country in a caseLesson in Markets and economies: the world a case lives in
- Estimating anything from almost nothingLesson in Market sizing and estimation
- 60-second structures and fast sizingLesson in Speed and precision
Related terms
- Market sizingEstimating how big a market or quantity is.
- Bottom-up sizingStart from a small unit and scale it up.
- ExhibitA chart or table the interviewer hands you to reason from.
- Percent versus percentage pointsA change in a rate is measured in points; its relative change in percent.
- CAGR (compound annual growth rate)The steady yearly growth rate that links a start value to an end value.
- Rule of 72Years to double is about 72 divided by the growth rate.
- Weighted averageAn average where each part counts in proportion to its size.
- Lakh and croreIndian number units: 1 lakh = 100,000 and 1 crore = 10 million.
Learn it in context
See Top-down sizing at work in a lesson from Guesstimates and market sizing, with checks as you go.
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