I think an economy is a region with a 'scope' that depends on the discussion at hand. You could speak about the ecnomy of Colombia in isolation, or you could look at the economy of Latin America as a whole. When comparing you'd compare Latin America as a whole with for instance North America, Europe or Asia.
It is common to compare the US economy vs the EU economy or all of Asia, not to compare the economy of Germany with Texas.
Usually regions that can be lumped together share a border.
To make the comparision more fair I think if you wish to compare 'apples with apples' as much as possible probably the inclusion of the NAFTA region would be more appropriate when comparing with the EU.