Hi,
I consider great the approach of the other candidate below. To facilitate the calculation I would find the hours played in total (starting from the people and the frequency) and then estimate the balls needed every year.
To add the aspects related to tennis academies and professionals I would simply add a percentage at the end.

Best,
Antonello

US Population --> number of potential tennis players (e.g. age 10-70) --> rate of people that actually play tennis --> divide those people into categories (rarely play, occasionally play, frequent players) --> assume how many balls they need per month/per year --> multiply this number by price per ball

That's the easy way. If you want to complicate things you could add tennis academies, schools and professionals as well.

(edited)

Hi there,

Providing some market sizing thinking for anyone revisiting this Q&A:

Remember that there's rarely a "best" answer with market sizing. What's important is that you break down the problem the way it makes sense to you. Importantly, break it down so that the assumptions you make are the ones you're most comfortable in.

For example, do you know all the major brands? Great go with that. Do you understand all the segments of that country's population (either age or wealth or job breakdown)? Go with that. Do you know the total market size of the tourism (or hotel) industry? Then break it down that way.

Some tips:

1. Just like in a case, make sure you understand the question - what are you really being asked to calculate
2. Decide whether a top-down or bottom-up approach is best
3. Figure out what you know you know, and what you know you don't know, but could estimate
   1. This helps you determine how to split out buckets
4. Stay flexible - you can start with a "high-level" market sizing, but gauge your interviewers reaction....if it looks like they want you to do more...then go along level deeper in terms of your splits

Hello,

I would suggest the same approach to calculate the number of hours played. Then you have to calculate the number of games playes:

• Estimate the duration of a game
• Calulate the average of players per game (between 2 and 4)
• Games played = Total hours played / (# players per game * Hours per game)

After this you have just to estimate the number of balls per game and how many game you can play with the same ball.

Tennis balls needed = Games played * # balls per game / # games per ball

Hope it helps,
Luca