Expecting a group of civilian from one nation moved out because of these factors:
1: Discovery of essential techs:Magnetics, or navigation
2:Over-populating or other unhappiness factors
3:Under totaliarian govs(Fascism, communism, monarchy...after the discovery of democracy by more than 2 countries)
4:Be economic or/and production backwards
5:Tech backwards
6:Scientists have a tendency to live abroad because of factor 5.
7:Rioting and starvation will drive more people away, from nearby cities
These factors encourages peace, democratic builders.

I forgot: Culture and histrorical (War and Peace) factors should be considered.
Communist can build Wall of Berlin to decrease this tendency.
Corruption affects people from living in border.
MPs,Police Station and courthouse can affect this. (As encourage and disencourage migrants)
Propaganda can affect migration.
Propaganda press, radio station , TV station and Internet affects migration.
Nationalism,Communism and Fascism decrease this tendency.
Foreigner has bigger chance to emigrate.
University attracts scientist.

Doesn't seem like a bad idea but what about the aspect of assimilation. I wonder should these citizens more easily assimilate when compared to a conquered city? After all some of the situations you've outlined would mean that the citizens have moved under their own free will. Then again this leads into another aspect of immigration should there be a difference between immigrants or migrants and refugees. Should immigrants assimilate more easily whereas refugees wouldn't -- and if the situation in their home country improves would they go back?

Also if they are moving to your civilization I think there should be an option to accept or refuse them creating repercussions in themselves. For instance refusing refugees will lower your rival's opinions of you -- unless one of your rivals is under a totalitarian government and you are allied with them. Maybe tolerance could be introduced as well in this sense. A civilization in the Industrial Age would be more opposed to immigration from a dis-similar cultural group thus having an intolerant view -- and if you accepted these immigrants your approval rating would go down and your citizens would become unhappy. Whereas a more advanced civilization wouldn't care where the immigrants came from and would welcome skilled immigrants like scientists -- thus having your approval rating go up along with the happiness level of your citizens.

Sounds like a good idea, they make should be realistic, by increasing the population UNhappyness and have the migrants not contribute to the city in any way. So they consume food, cost about 5 gold each, cause unhappyness with no benefits.

This really would be realistic then!

How FUNNY, I was just thinking of this exact same thing last night. A city with a lot of discontent people could have some of their population move to another countries city with higher culture/happiness etc. This has happened a LOT in the past (though mostly for economic concerns). Who built most of the railroads in america? Chinese and Irish immigrants (mostly)... Starvation could be modified, if a country is 'starving' itself, most of the population would at least TRY to move to greener pastures rather than waiting for an untimely demise.
Assimilation should be standard, but not much of a factor, they left a country because of harsh conditions, unless both nations involved did major changes in a short time (which could also give you the ability to get lost citizens back).
I disagree with you on one point Primeminister. A nation may WANT to keep out immigrants, but that doesn't mean they can...

*Concept) Cities will naturally have a limit to which they want to grow. This limit is based on technology, infrastructure, and the local economy. Whenever this limit is passed, citizens will attempt to migrate to a city that fits their needs. For migration purposes, nation pride weighs in heavily whether a citizen emigrates or migrates. If no city is found, they will make the difficult decision to form a new city.

*Technology Population Limit) As technology progresses, cities can support more people and products comfortably. Such technologies as Construction, Engineering, Sanitation, Steam Power, Motorized Transport, etc., will increase this basic support limit. I'm not going to list what this number is after each advance, but it shoudl probably start at 1 or 2.

*Facility Population Limit) The presence of certain facilities in a city adds to the amount of people it can support, the quantity of jobs it creates, and the overall desirability. Example of the second and third would be Cathedrals and Temples, which create an economy based off of increased religion(Roman city of Corinth is a historical example). Example of the first would be Aqueducts and Hospitals.

*Citizen Needs) Citizens in a city have certain basic needs. These numbers are just suggestions for right now. All citizens need food, so two is the default minimum. All citizens need shields to represent production of goods for consumption. The amount of shields needed would increase over time. These shields are still used for production, but must exist in sufficient quantity to satisfy citizen demand. Example: There is five citizens in a city, who each need one shield of production. The city produces ten shields a turn. Ten shields will go into the current construction project. However, if the city only produced four shields, one citizen would not have their basic product need met.

*City Desireability) All cities have a different level of desireability. Food of course is a give, the more extra food, the more desireable. Production is another, since the more production per citizen, the greater amount of products they will have. Commerce per citizen represents trade and income potential. Luxuries and facilities also factor in. If a luxury is local, it is valued even greater because of its cheapness. Facilities add in desirability points. Each city then calculates its desire ratings. The process to rank cities with the same desire rating is currently unknown to me, but it should involve culture and proximity to cultural sites.

*Migration) Citizens will try and migrate under certain conditions. First, they are unhappy and over the optimal population limit. Second, their basic needs are not being met. Third, another city has twice the desire rating of the city they are in and is not at or over the population limit. Whenever they do migrate, they will try to migrate to the best city they are connected too. Since multiple citizens will want to move to the best cities, the pecking order is domestic worst city, domestic cities, international worst city, international cities.

*Immigration/Emigration Policy) You would have some control of citizens going in and leaving your borders. You can set quotas on immigration from specific civilizations and limits on emigration. Of cours your immigration/emigraiton policy may make you unpopular with other civs.

*City Growth Policy) You would have some control of whether cities would try to do with growth. You could tell cities to Encourage Growth, Encourage Migration, or Encourage Stability.

*New Information) Each turn you would get a summary of the total amount of domestic and international migration. You would also get a summary of growth in your cities, so you could change policy whenever you needed to.

How FUNNY, I was just thinking of this exact same thing last night. A city with a lot of discontent people could have some of their population move to another countries city with higher culture/happiness etc. This has happened a LOT in the past (though mostly for economic concerns). Who built most of the railroads in america? Chinese and Irish immigrants (mostly)... Starvation could be modified, if a country is 'starving' itself, most of the population would at least TRY to move to greener pastures rather than waiting for an untimely demise.
Assimilation should be standard, but not much of a factor, they left a country because of harsh conditions, unless both nations involved did major changes in a short time (which could also give you the ability to get lost citizens back).
I disagree with you on one point Primeminister. A nation may WANT to keep out immigrants, but that doesn't mean they can...

I think it would be good to be able to "build" emmigrants/migrants who can join another civ. The result would be that civ now has extra workers, but the chance of defection may go up.

What do you guys think? Somehow I would imagine some people might try to use this as an exploit so I think perhaps there would be a limit as to how many migrants can to a city per so many turns. Kind of like how drafting citizens works.

I like your factors, but those are all very modern ways of looking at migration. A lot of people moved between nations well before that. I think the key would be a huge disparity in the quality of life, that's basically it. If you have unhappy citizens, and another nation is very happy, then you should probably see a lot of migration... unless they're xenophobic or at war.

I like your factors, but those are all very modern ways of looking at migration. A lot of people moved between nations well before that. I think the key would be a huge disparity in the quality of life, that's basically it. If you have unhappy citizens, and another nation is very happy, then you should probably see a lot of migration... unless they're xenophobic or at war.

I agree, people want better quality of life. My system was just to quantify that fact.

Point taken :) Often I just start out by replying to the thread-starter.

If there was a poll I'd vote "Yes" twice :D

I don't think this is a unit that should be built. They should just automatically pop-out if the conditions occur.

@ sir_schwick If the food distribution ideas from other threads (such as if city has a granary and is on trade network, it can send/receive food within empire) are implemented, that would make a large difference in meeting citizen needs. It will also make protection of the domestic trade network even more vital during war.

If these little units do pop out, can enough leave a city to completely abandon the city? If the city is on a very small island, what do the units do? Would they have the ability to hail/board opponent's ships or hire barb ships? This also would require careful coding or brand new cities will have a problem developing.

I also think that if you frequently rush projects via whipping or use conscription too much some of the citizens will want to leave. In a way those concepts do fit in with sir_schwick's post since the productivity of the cities would be affected, but the idea should be explicitly stated.

If pollution stays in the game (which I hope it doesn't in current form), citizens should also want to leave a very polluted city and join a clean one.

Emmigration(domestic and foreign) from cities only occurs whenever the optimal number of people is passed, or conditions in another city after a great deal better, 200% or more perhaps. New cities will not pass that limit until they start getting larger. EVen early, undeveloped cities would have a limit of 2 or 3.

As for units stuck on islands, hiring out a barb or merc transport would be interesting. It woudl also solve the problems of sea transport early. WE could also consider the RoN system, where units are automatically assumed to have transports.

I disagree with you on one point Primeminister. A nation may WANT to keep out immigrants, but that doesn't mean they can...
The US passed several laws in the late 1800s and early 1900s limiting Chinese immigration to the USA. But people could always come in illegally...

If I remember correctly it did stop most of the immigration of Chinese nationals though. No immigration policy will prevent immigration or emigration, but it reduce the impact it has on populations. Leaving Cuba is a lot harder than leaving the US. Many people still leave Cuba, but the relative % of population is very low.

Black market immigration would not add enough population to be considered significatn(i know this is a different factor with Mexico, but those workers are often migrant).

I see Refugees might come into the game Great Idea

The US passed several laws in the late 1800s and early 1900s limiting Chinese immigration to the USA. But people could always come in illegally...

Just look at Mexico (although many are leagal many are not) (not meaning offence to any Mexicans that may be out there)



Also, I think immigration should be higher in cities with direct Road/rail/harbor/airport access to the other civs and, at least with road/rail access it should also be baised on proximity to the civ.