So only pops who decides no to migrate to colonies and internally WILL try to go externally?
Nope, there is no forced relationship whatsoever between the three types of migration. A POP won't think 'I'm not going to migrate internally this week, so I'll have more people migrate to the colonies'. It's three entirely separate processes.
Also, is the CON effect on migration correct? I´m not 100% sure I agree with the CON factors in AHD. Or maybe CON is being acquired too fast, that could explain why so much Indian migration going on. Also, shouldn´t cash also play a role? No money, no overseas travel.
It's 'correct' in that what is reported in game is the values in poptypes.txt. It's not 'correct' in that those values give the right amount of impact on migration, which is part of the reason the Devs have changed migration in the forthcoming patch (see DD15).
That helps, but I'm still uncertain about what affects the weighting on 'country_migration_target'. The raws says that being in America and being a democracy helps, and the game suggests that political and social reforms help, but there seems to be more to it than this. Does setting an 'attract immigrants' national focus improve the weighting for country migration, or only internal/colonial? Does RGO value and industrial strength help? What about prestige, or country ranking?
Chille tends to get a lot of immigrants at the start - is this because it has gold, or because its a democracy with some political reforms?
'Attact immigrants' does nothing to influence country_migration_target. So you could have 5 of the things active in your country, but it will still only effect the province targets, rather than the country choice. It's an internal thing, as is most designed so that the USA can migrate people west quickly if it wants to, I imagine.
Chile's immigration is entirely based on it being a democracy, and nothing whatsoever to do with having gold - the gold mines will attract people who are already in Chile, or are already going to Chile anyway, but have no effect on country_migration_target.
Let's put together an example and run through it. This is the Craftsman country table:
Code:
country_migration_target =
{
factor = 1
modifier = {
factor = 0
NOT = {
work_available = {
worker = craftsmen
}
}
}
modifier = {
factor = 0.1
unemployment = 0.1
}
modifier = {
factor = 2.0
has_pop_culture = THIS
}
modifier = {
factor = 1.05
government = democracy
}
modifier = {
factor = 4.0
OR = {
continent = north_america
continent = south_america
}
}
}
All values are mulitpliers, rather than additive. Let's assume that all nations start with a weighted value of 1.
So, the first value checks if a nation has work available for craftsmen - note that this does NOT mean it checks if all the factories are full, merely that it checks that there are factories at all. If not, craftsmen simply won't go there, the nation will have a 0 weight on the weight table and so it will be impossible for it to win the targetting roll. All nations with no factories are therefore basically off the weight table now.
The next value checks if the nation has 10% unemployment or greater. If so, it reduces the weight value by 90%. Let's say that Equador is unfortunate enough to have 10% unemployment, while the USA has only 4%. So now Equador has a weight of 0.1, and the USA has a weight of 1.
The next value checks if there's already this POP's culture present. This is mostly for performance reasons, I'd guess. Let's pretend that Equador has the culture, but the USA does not; so the USA's avlue remains at 1, but Equador's is doubled - so, with it's unemployment, it now has a weighted value of 0.2.
Then there's a democracy check. This is only a 5% bonus, but for the sake of argument we'll say Equador has fallen into Tyrany and the USA has not. USA weight = 1.05, Equador is still on 0.2.
Finally, the Americas check has a massive 400% weight bonus. Both nations are in the Americas, so now the USA has a weighted value of 4.2, and Equador has a value of 0.8.
The game works out this table, and then does a random roll, which in this case means that about 85% of craftsmen emmigrating will go to the USA, and about 15% will pick Equador. This isn't exact - it's a random roll, so sometimes 20% might go to Equador, sometimes 10%; on very rare occasions 100% may pick Equador. But over time, the average number of craftsmen of this culture picking each nation will be 15% Equador, 85% USA.
Now, if Equador suddenly manages to pull unemployment down below 10%, it will shoot up to having a weight of 8 - twice that of the USA. Now, on average 60% of migrants of this poptype and culture will pick Equador.
I should probably c&p some of this stuff over onto the wiki.