POP has some factor to encourage grouping when choosing within country, however the main overhead reduction logic is in merging small POPs (even if they have mismatching attributes)
I'm aware of this. This is actually one of the reasons it's difficult to tell with any certainty what's happening. If the game didn't do this, we could see exactly what POPs are going where. Unfortunately, I don't think we can.
That's wrong belief though
If you start the game and watch carefully who is going where you can see that this hypothesis is wrong - pops with the same attributes will go to different countries on a regular basis. Instead of tracking exact movement you can just see statistical results.
I'm not sure you could prove that I'm 'wrong'. Again, if you don't know the exact mechanism, you can only guess as to why you're seeing the results you're seeing.
For instance, that trickle of POPs that goes to other countries (on a regular basis?), which is so tiny that you may as well not consider it in most cases, as I previously explained, is due to other factors making those targets more desirable. Maybe my use of the word 'all' threw you off; when I say all, I simply mean the vast majority :rofl: It is pretty easy to simply load up V2 and see that it's not 'all'. Then again, it's also easy to see that only 1-3 countries in the new world receive the vast majority of immigrants, another 2-4 recieve a trickle, and the other 15-20 receive exactly 0. This is the problem that I aim to fix.
Oftentimes, one country will receive the vast majority of emigrants from a specific other country on a given day. The times that you see POPs migrating more equally are from places like Austria, Russia, France, Germany, Ottoman Empire, etc, which are multi-cultural regions with also multiple religions, which have different factors for each of the different POPs dictating where they will go.
Statistical results in Vic2 are consistent with you're suggesting except it distributes whole POPs instead of splitting up and distributing individual POPs
You're wrong. Maybe I need more explanation. Also, I never suggested they split POPs, though that is one way of doing it. I was thinking more along the lines of each POP having a chance to emigrate to several targets based more closely on the proportional draws towards emigrating to those targets, in the hopes that this way would cut down on overhead.
Even if my analysis of the problem isn't exactly correct (indeed, none can be), my analysis does as good a job of explaining the current situation as any other. And my suggestion to change the situation is that POPs be more proportionally distributed based on the factors for each country, whereas now the vast majority of all POPs go to 2 or maybe 3 countries in the Americas. In Vicky2, immigration chance is FAR from proportional. If you pass a reform as Ecuador, you will probably still see 0 immigrants because the other factors in your country make you an 8th choice for most POPs. What I'm suggesting is that when you increase your immigrant attraction, you should receive more immigrants, assuming you have a significant immigration chance compared to other targets (so, Burma passing a reform doesn't get more immigrants because it still only has 0.1% of the draw of the top immigration choice for any particular POP).
One of the reasons I really like Vicky2 is that it is somewhat less focused on warfare than the other Pdox titles (I've shelved EU4 because the gameplay seems to revolve around warfare... either you're fighting a war, or you're preparing for one...). Migration and immigration is actually one of the weaker points of Vicky2, in my estimation. It's fairly complex but not very dynamic for all that complexity. If I could focus on creating a European or Asian economic powerhouse with liberal ideals, I should be able to work peacefully towards growing through immigration, even if it is only a fraction of the USA's immigration in the end.