Factors to be consider in compering enter country GDP

1. Large country trend to have hire total GDP. Therefore a better cooperation is GDP per head per capital.
2. GDP needs to be consider in real terms rather than nominal terms 
3. GDP needs to be converted into a common currency (US dollar).
4. GDP figure can only include factors on which information is available
5. GDP figure don’t make reference to the distribution income between countries.
6. GDP figures make no reference to the social cost of production