A Message From John <middlename> Smith
07.20.2020 - Today's market sizing exercise
Hello Case Dojo,
The section for John Smiths likely takes up many pages in the phone books. Good luck and have fun!
Reminders
Spell out your thinking process, state your assumptions, and evaluate your final answer. There are many valid approaches to each problem.
No calculators are allowed, so make the math easy for yourself.
Try to come to an answer within 3-4 minutes at the longest (here’s a timer).
Today’s Question
How many people in the US are named John Smith?
Our sample answer
How we broke things down
We start off with the total number of males in the US.
Multiplying that by the percentage of males named "John" yields the number of Johns.
Next, we multiply the number of Johns by the percentage of Johns with surname "Smith"
Assumptions we made
The US population is 320M people and 50% are male.
Only males are named "John."
5% of people in the US are named "John" and 1% have the surname "Smith."
Our evaluation
We arrive at 80,000 John Smiths. This is likely an overestimate as there is probably a very high diversity in male names, and any given one, even one of the most common, would have a lower incidence rate than 5%.
Other potential approaches we like
Break down the population by age group, and estimating the percentage of John Smith's in that group
Break down by region in the US
Actual answer
There are 44,935 people named John Smith in the United States.
Extras
If you like the work we do, please share Case Dojo with your like-minded friends!
🤠 Fun Fact
John has stayed consistently popular for boys, though it has slid from number 1 to number 28 in most common boy names over the last 100 years.
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