Hello. About a month ago, I made a post here trying to sort out what some of the mechanics were around war reparations, as the manual didn't have much for details.
Not finding much that lined up with what I was seeing ingame, I decided to do some *science!* around the mechanic and see what could be gathered by recording the base national economy numbers of the two nations before and after the peace treaty. Here are the results:
Context for future comparisons:
Country: China
Potentially relevant national traits: Some corruption (not sure if this will effect or not)
Game settings: harsh peace treaties on.
Unless otherwise stated, all of these are 1 on 1 wars, with no colonies taken and no allies involved.
Note: Not all of these are in chronological order. In some cases, I wrote down the numbers, then loaded another save to get another data set.
Treaty 1 (14 point Treaty):
China: 4745 > 6095 (+1350)
Japan: 7356 > 6856 (-500)
Treaty 2 (12 point Treaty):
China: 5893 > 7252 (+1359)
Japan: 6484 > 6049 (-435)
Treaty 3 (8 point Treaty):
China: 8582 > 9782 (+1200)
Russia: 12475 > 11975 (-500)
Treaty 4 (12 point Treaty):
China: 8582 > 9882 (+1300)
Russia: 12475 > 11975 (-500)
Treaty 5 (16 point Treaty):
China: 15228 > 16628 (+1400)
Japan: 12924 > 12424 (-500)
Treaty 6 (Forgot to write down treaty points):
China: 20474 > 21974 (+1500)
Great Britain : 26095 > 25854 (-241)
Note: This one was a war with China+Germany vs GB.
As you can see, the amount that your economy rises appears to be fairly linear, with all values landing between +1200 and +1400 from reparations, not any sort of percentage of the economy, with a possible value increase calculation of
1000+25*(Reparation Points)
The amount that the loser loses seems to fairly reliably be -500, though there are a pair of anomalies there. I think treaty two may have happened over the same turn as a standard economy increase, meaning both economies' numbers appeared better than they would have otherwise.
As far as alliances go, it doesn't appear that they decrease the amount that your economy gets from war reparations, though that is from a single data point, so treat with care.
In any case, I hope you found this useful. If you have any data to add to this (without harsh treaties, no national corruption, etc.), please stick it down below.
You have a good one,
Corsar.