Interesting case, let me give you my 2cents:
- By market sizing are we focusing on volume or $?
- How big is the Pop. in Country X?
- Is there any special consumer behavior in this country or can I assume regular consumption (i.e. my own Country)
- Is it ok to assume the market will just be regarding for human consumption?
I'm going to estimate the average consumption per person and then multiply by #Pop. X. There are several ways to estimate it but this sounds the fastest one.
There are 2 big meals per day (Lunch/Dinner);
I'm going to assume I have one meal containing potatoes for every 3 meals (I'm saying this because people eat more rice and pasta in my country when compared to potatoes, however, this can change for this particular country);
I'm going to assume 200g of potato consumption per potato meal. This will equate to a mid size portion of potatoes;
Meals per year = 365x2=730 meals which 1/3 is with potatoes = 240 meals; each with 200g of potatoes = 48 kilos of potatoes per person
(Quick Sanity check: In my family of 4 I usually bring a new 40-50kg bag of potatoes every 3-4 months so 48kg per person surely seems reasonable)
I'm going to assume Population of Country X is 10M for simplicity if we don't have any data.
Market Size = 10M x 48 kg = 480,000 tons
I actually after doing the math went to check statistics and all these numbers make perfect sense.
numbers here are not important, what is important is:
Ask necessary questions to reduce scope and to cancel any misinterpretations;
Take time and draw a framework that can solve problem;
Add numbers to the framework using reasoning and your own experiences;
When obtaining numbers always check if said numbers make sense;
Present final value and add some final conclusions if pertinent.