GDP calculation long-read

[Abuse_Claws]

So I'm looking at my Spanish campaign that I play since 1.09 beta. So far it goes from 1890 to 1943, and I'm beginning to wonder: is the GDP we have in-game correct both from historical and gameplay standpoint?
Warning: I'm no economist and may be majorly wrong about pretty much anything here, so if you spot an error please bring it up in the comments.
Note: I use point for decimals and coma for thousands.

The first question that comes up is: what are in-game dollars? Seriously, what does one in-game dollar mean compared to IRL dollars?

From a fast google search or two, usually 1990 international dollars are used for historical GDP values, which are basically the equivalent of a 1990 US dollar. So let's try and convert in-game money to those.

Iowa-class battleships cost the US government about 100 million 1940 US dollars, which (if the online inflation calculator I used is corect) would be 934 million 1990 US dollars or international dollars. 

My in-game Rosa-class BBs have 82.4 thousand tonnes of displacement (compared to Iowa's 58.4) and have 4x3x16" guns compared to Iowa's 3x3x16", both have 33kn top speed.

So we could roughly estimate my ship to be 1 1/3 of Iowa's cost, which would bring it to about 1,245.3 million international dollars. In-game Rosa costs 516 million dollars, which would suggest a course of 2.413 international dollars for an in-game dollar.

Let's double-check this estimate:

A Fletcher-class DD IRL cost 6 mil, convert to international bucks - we get 56 mil, divide by 2.413 and we get 23.2 mil in-game dollars per ship. When I tried to design a sorta-Fletcher class in-game, it cost 29 mil per ship, which is close enough (1.931 vs 2.413 conversion we had before).

Since this is not a scientific paper, I'm inclined to take the average and go with it: 2.172 international 1990-s dollars for 1 in-game dollar.

So, what the in-game GDP should look like in 1943?
Note: I'm disqualifying Austria-Hungary (as it didn't exist IRL at the time) and China (as in my campaign it dissolved decades ago)
Note 2: I'm using numbers from "Military production during World War II" Wiki page
Note 3: all figures in billions of in-game dollars, converted from international dollars using the coefficient of 2.172

• USA IRL had a total GDP 379.4 compared to 42.9 in my campaign
• Germany (without occupied lands): 196.1 vs 89 in my campaign
• Britain (without dominions): 291.5 vs 94.7 in my campaign
• Russia (USSR?): 140.4 vs 26.6
• France: 73.2 vs 41.9
• Italy: 73.7 vs 18.7
• Japan: 118.3 vs 12.9
• Spain (it's not in the Wiki article, so I used the numbers from this paper): 66.3 vs 75.4

What we see is for all countries except the player country the number is way too low, and considering that raising GDP was my top priority AND in-game there is no Spanish civil war, that IRL had an enormous negative impact on Spanish economy, we can say that for Spain it's too low as well.

What are the reasons?

1. Wars. Excessive, never-ending wars. Austria-Hungary in particular is willing to pick a fight with everyone at once while having only two dozen DDs left in their navy. The issue of wars being too frequent in 1.09 is so often brought up that I won't discuss it any further here
2. Wars having a weird impact on the economy. For example, if I'm only at war with AH, an empire with less than half my GDP and only a bunch of destroyers left in their fleet, why is my GDP tanking? It's not like they have any chance of disrupting my trade or sank any of my transports. And on the flipside, *their* economy should be in shambles, as they are at war with half of the world and have no way of defending their convoys. And yet their economy is shrinking at about the same rate as mine
3. AI priorities. The AI needs to prioritize GDP growth more, plain and simple.
4. Unrest having no impact on GDP. Countries with low unrest should recieve a GDP bonus, while those with high unrest should get penalized, especially if they come to a point of an actual revolution.
5. The GDP and its growth rate possibly just straight-up being too low from the start
6. ???

I would say that it's something that does need fixing, although the prospective of AI having more money for their doomstacks... Yikes.

 

[Lima]

Interesting. Here is my data (1890-1932). Don't pay attention to the stronk Russian Empire, it's me. Germany and Austria are under blockade.

As far as I understand, at the very beginning of the game, each country receives a certain GDP growth coefficient and it does not change much over time. In this case, I had the highest coefficient, Italy had the second. On a long road, the results are very visible (I also try not to fight for a long time).

[Abuse_Claws]

Yet if the doomstack issue is solved and AI actually tries to keep its fleet at least semi-modern (in my campaign in 1943 some countries still have TBs in service for crying out loud, and their tech is "Very Advanced"), the increased GDP would be a good thing I think, as it would speed up research (which is currently, at least in my campaign, way behind schedule for some branches in all countries), allow for larger fleets of modern ships and more room for experiments with different designs.

[Abuse_Claws]

1 minute ago, Lima said:

Here is my data (1890-1932)

Interesting. You seem to have way more realistic values than I do. What difficulty are you on and what type of AI did you set? Mine are normal and random respectively

[Abuse_Claws]

3 minutes ago, Lima said:

As far as I understand, at the very beginning of the game, each country receives a certain GDP growth coefficient and it does not change much over time

IDK if that's the case. In my playthrough initially Britain had the highest growth rate IIRC, followed by Germany and US, while mine was down in the shitter. Now, however, Spain and US have basically switched places, with Britain and Germany still being way ahead

[Lima]

1 minute ago, Abuse_Claws said:

Interesting. You seem to have way more realistic values than I do. What difficulty are you on and what type of AI did you set? Mine are normal and random respectively

Normal/historical.

[Lima]

2 minutes ago, Abuse_Claws said:

IDK if that's the case. In my playthrough initially Britain had the highest growth rate IIRC, followed by Germany and US, while mine was down in the shitter. Now, however, Spain and US have basically switched places, with Britain and Germany still being way ahead

I can say for myself and for Italy/France, we are stable 1-2-3 by GDP growth. Of course, wars and the number of transports affect this value.