There are many clever ways to try to get a grip on a GDP; one method used these days in Africa and for North Korea (as well as to estimate corruption in official figures) is to measure energy usage or if that is too hard to estimate, simple night light emission via satellite. I believe the CIA used many different metrics in its various estimation.
There are many clever ways to try to get a grip on a GDP; one method used these days in Africa and for North Korea (as well as to estimate corruption in official figures) is to measure energy usage or if that is too hard to estimate, simple night light emission via satellite. I believe the CIA used many different metrics in its various estimation.