Question regarding reported GDPs

[Kanaria]

I am the proud owner of nearly 50 nations on NationStates, and my four largest and longest-active nations on NS have similar populations and economies, kinda.
One thing that always made me wonder, though, was this curiosity. It concerns the fact that the second-youngest of my four oldest nations has the biggest GDP despite having the second-smallest population and second-strongest (or largest?) economy. Its' economy is at level 99 or Frightening as I type this.
src: http://www.nationstates.net/nation=the_united_colonies_of_earth

The Galactic Federal Republic of The United Colonies of Earth...The compassionate, democratic, cheerful population of 8.991 billion Colonists...The frighteningly efficient human economy, worth a remarkable 1,927 trillion UN Credits a year...

The largest and longest-active nation I have, however, has an economy of 100 as of my typing of this, and a smaller GDP.
Src: http://www.nationstates.net/nation=east_catalina

The United States of East Catalina is a gargantuan, genial nation...The compassionate, democratic, cheerful population of 10.063 billion East Catalinans...The frighteningly efficient East Catalinan economy, worth a remarkable 1,633 trillion UN Credits a year...

The second-largest and second-longest-active nation I have has a slightly larger GDP than the largest nation and an economy of 96 or powerhouse.

The State of Big Brain City is a colossal, safe nation...The compassionate, humorless population of 9.089 billion Brainishpeople...The powerhouse Brainish economy, worth a remarkable 1,684 trillion Brainish Credits a year...

The smallest of these four nations by population and the youngest of them, this one, actually does have an economy that seems to go along with the theme. It's got the smallest GDP and third-strongest economy as I write this, with a rank of 97. From http://www.nationstates.net/nation=kanaria:

The Federal Republic of Kanaria is a colossal, environmentally stunning nation...The compassionate, democratic, cheerful population of 7.645 billion Kanarians...The frighteningly efficient Kanarian economy, worth a remarkable 1,557 trillion Kanarian Dollars a year...

e: Oh I forgot my question!
So, yeah, I was wondering why the UCE has the biggest GDP despite its' economy or population not being the largest as well. I'd appreciate responses explaining why this is so.

[[violet]]

GDP is mostly determined by:
1. Population
2. Raw size of government
3. Raw size of industry
4. Economic efficiency

#4 on that list is the basis for the "Economy" rating on your nation's front page, and it describes how efficient your nation is at extracting economic output from resources (like people and capital).

All four of the nations you describe have very high "Economy" ratings, and are pretty much indistinguishable from each other on that score. They're also very similar in terms of population, and having very high tax rates, and the fact that the majority of economic output comes from government activity. So the difference almost entirely comes from how relentlessly you've been building up government in those nations. UCE has the biggest government. And that will be because UCE has addressed more issues in a pro-government way.

[Kanaria]

GDP is mostly determined by:
1. Population
2. Raw size of government
3. Raw size of industry
4. Economic efficiency

#4 on that list is the basis for the "Economy" rating on your nation's front page, and it describes how efficient your nation is at extracting economic output from resources (like people and capital).

All four of the nations you describe have very high "Economy" ratings, and are pretty much indistinguishable from each other on that score. They're also very similar in terms of population, and having very high tax rates, and the fact that the majority of economic output comes from government activity. So the difference almost entirely comes from how relentlessly you've been building up government in those nations. UCE has the biggest government. And that will be because UCE has addressed more issues in a pro-government way.

Cool! I didn't know that before today. Thanks for explaining it to me!

[Drachmaland]

That's a great opportunity to ask about how off the NSE/NT calculations are, for from here I get:
EC:-- GDP = $464,639,663,432,661.00 (1 UN Credit = $1.9994)
UCE: GDP = $410,491,420,721,575.00 (1 UN Credit = $1.9880)