hi there, 

for this question we are asked to calculate the current market for IBC.

in normal situations in market sizing, we draw our own structure and then include assumptions to then estimate market sizes independently. In this case there is data available on the male female and teenager markets. 

How would I know when to perform the market sizing independently or when i would need to ask for data? I thought that you do the market sizing without external data and you make logical assumptions or use previous data provided from the clarifications in the first part of the case. however if I do this in this case, my structure is different because i am estimating market sizes without product pricing data etc. 

please see https://www.preplounge.com/en/consulting-forum/market-sizing-ask-interviewer-for-data-points-first-or-develop-own-structure-and-present-for-initial-review-16785 for comparison. 

i am new to preplounge so sorry for bad english because i am not native english speaker. 

many thanks and I hope to ask more questions in this community!