What are the difficulties in comparing national income between countries?

Answer 1

research, read, point form notes

https://www.google.com/search?q=What+are+the+diffi...

Answer 2

The main one is the cost of living in those countries.

If a product costs $1 in the US it could cost $1.20 in one country and only $.23 (cents) in another.

The same thing happens in the US.  A $100k/yr job sounds great.

If you earn $100k in LA or NY you're money is mostly spent before you earn it.

If it were possible to earn that much in another state you'd be able to save 25% of it.

I've moved between states where a 2 br apt was cheaper than the 1 br I left.