Population
Population in game represented as a set of separate units (aka pops) with it's own attributes such as culture, type (class, like Tribesmen or Capitalists), money amount and so on. Each pop lives his own life producing things, consuming thing, voting for desired reforms. Pops have needs - some products they need consume to survive and enjoy life. Needs splitted in three categories: life needs (pop will starve without it), everyday needs and luxury needs (luxury needs aren't limited implementing people's endless needs). Pops buy cheap products first. Pops wouldn't buy luxury products if everyday nor life needs aren't fulfilled. Each time pop receive payment he pays income tax basing on country tax level. Pop pays income tax to income source country. If income source is product market than pop pays tax to pop's country.
Every pop unit has a Loyalty procent (loyalty to his current country). Low loyalty pops can join movement or even rebel. Loyalty also affects mobilization procent. Loyalty growth depend on: pop's consumption level, ability to vote with given regime, minority politics, province modifiers ("recently conquered" reduces loyalty of minorities), government ability to rule country (just gives penalty for to big country). Also forcing reforms and not paying promised social benefits would ruin loyalty.
Those modifiers could be seen in population window tooltip:
If pop fulfilled needs for less than 30% than he start to looking for better life. It could be: emigration, migration inside country or demoting to a lower class. Or he can just starve to death. Pop select way of life basing on highest average consumption level for every option. If some pop fulfilled needs for more than 40% he can improve his social status, for example Tribesmen promotes to Aristocrat. But that happen only if Aristocrats have higher consumption level and job available (for employable classes).
Population can increase Education consuming special product called Education. Education increases population production efficiency. Plus hireable population like Workers will be hired in "better educated - first" order. Workforce education has bigger influence on processing enterprises, smaller - on resource gathering enterprises and significantly big influence on efficiency of University. Also, employees can improve education just by working on processing factories (though there is some cap, so Universities are still needed). Education level may drop down if pop stopped learning. If you want to build government education system you may nationalize or subsidize universities. Though, since currently there is only one (common) market in game now, your education subsidies could be consumed by foreign citizens. Education growth rate isn't linear, to achieve higher level pop should consume more education.
Aristocrats are conservative class who invest in local resource production and exploit farmers. Their favorite government is Monarchy. Aristocrats don't pay taxes with Monarchy government. Money income: resource enterprises income + farmers dues(*) + pillaging(*) + bank interest(*) + loans + share sales. Aristocrats can't promote any higher but demote to Farmers, Tribesmen and Soldiers.
Capitalists now can invest in 4 ways: building new enterprise, expanding existing enterprise, reopening a bankrupt and buying shares of an enterprise. They can invest in own province, in own country and in foreign countries where it's permitted. Money income: dividends from enterprises + bank interest(*) + loans + share sales. Capitalists can't promote any higher but demote to Farmers, Artisans and Soldiers.
Money income: own production sells. Artisans promote to Capitalists and demote to Workers and Soldiers.
Produce grain. Money income: grain sells + unemployment subsidies on overpopulation(?). Farmers promote to Aristocrats and Capitalists and demote to Workers, Tribesmen and Soldiers.
Tribesmen are wild creatures living natural economy herding Cattle. Money income - non, they don't trade paying taxes with Cattle. Tribesmen promote to Aristocrats and demote to Workers, Farmers and Soldiers.
Needs Professional Army invented. Money income: only government salary. Soldiers promote to Aristocrats, Artisans, Farmers and demote to Workers and Tribesmen.
That's the only class which can be hired to work on Enterprises gaining some salary. Money income: salary + unemployment subsidies. Workers promote to Artisans, Farmers and demote to Soldiers and Tribesmen.
Clerics
Bureaucrats
maybe slaves
- - not implemented