Cities without city radius, self regulating economy, wealth

[Blake]

Here I believe is a rather novel City model where cities don't have a city radius, or worked tiles, or anything like that. A city is just a centre of population where labor intensive facilities can be built. Improvements are independent and send produce to cities using a self-balancing economy. Here is the basic idea, using Cities (contain population, consume food) and farms (produce food).

Cities have population, which needs to eat.
Cities have a food stockpile which the population eats from.
The demand for food at a city is equal to the inverse of the amount of time the stockpile will last ie.
(Population * ConsumedPerPersonPerTurn) / (1 + StockpileSize)

Thus a city with a smaller population is satisfied with a smaller stockpile.

Farms regulary produce food crates, they deliver the food crate to the city with the highest demand (modified by distance). Note that every time a city recieves a food crate, it's stockpile size increases, and it's demand therfore decreases. This means that another city may now have the highest demand, and the next food crate will be delivered to that city instead, hence the system is self balancing.

There are a couple of things to note:
City growth cannot be pumped up with extra food, rather population grows as a steady %age per year, around about 5%.
When a city has insuffecient food it's productivity decreases, we can say that people who arent fed dont work, another valid way of looking at is that if everyone only gets half the food they need, everyone works half as hard. This is the same as half the people being fully fed and working fully and the other half getting no food and not working at all.

International Trade:
If your cities are all well fed, the farms produce will become less valuable and they will look for more profitable markets, if the faction next door is suffering from starvation the food demand will be high and so your farms will send the food across the border.

There will be trade barriers which will make selling to other factions less profitable for the farmers, the barriers will act to reduce effective demand and the size of the barriers will depend on diplomatic relations and ordinances.
Trade Pact : 10%
Pact : 30%
Treaty : 60%
Truce : 100%
Vendetta : 400% (greed conquers all )

Ordinances:
Tariffs: +50%
Iron Curtain: +400%


The Farmers and their profits:
When the farmers experience periods of high demand they make scads of money, which they use to upgrade their farmland and increase production. Thus when demand is high, the farms get upgraded, production increases, demand goes down, less upgrading happens and everything is nicely automatically balanced.
Note: As the leader you zone areas as farmland, but dont actually bother with menial details like upgrading the farm land over time... it's up to the farmers to do that.

Money and Wealth:
More difficult but potentionally much more interesting is adding money into the equation, when food is sold at high demand the farmers get more profit, you get a %age of this profit as tax.
When trade goes across border you get a fair chunk of the barrier %age in forms of more profit from tax, this is especially true with tarrifs. This money is re-introduced into the economy when you spend it on production (buying services from the market).
Money could make all sorts of interesting things, like if your farmers are selling produce to your neighbour then your faction would get richer and your neighbours faction poorer.
When a leader hoardes too much cash their faction gets poorer because less money is in circulation.
Prehaps you could set the tax rate too, which would make production more expensive and the economy weaker, but give you more power, and the economy wouldn't be harmed too much if you spend most of the money in your faction.

The main challenge of money is "where it comes from", it basically has to be generated by economic activity and how is quite a challenge, atleast for what is a TBS game, rather than a TBEconomy game (in the TBE game you put the leader in charge of printing money and handling money supply and inflation and stuff, as a student of economics the very thought is making me drool, cold shower, baseball). For a TBS game the money supply also has to be balanced automatically, using some sort of system like economic activity generates wealth (ie everything you build and everything that is produced adds a bit of wealth or basically Money Supply ~ GDP)

The Farmers and their money:
With money every sale the farmers makes puts some money in their pocket, (and some in your hand in the form of tax, filthy bureaucrat). The farmers spend this money in the cities (reintroducing it into the city where it can be used to buy more food and generates you yet more tax!), and whatever the farmers have left over they spend on upgrading the farms. Once farms become fully upgraded if you dont zone more farmland the farmers become filthy rich, however the more upgraded a farm is the less effecient it becomes, so new farms will be more profitable than old farms and this will help distribute the income more fairly.

Extending the model:
If the basic infrastructure can be put in place (particullary the money) then this could be extended to other resources, like metals and uranium and energy, labor and whatsnot, everything would be automatically regulated by market forces. When you build military stuff it would raise the demand for metal, more metal would flow into the cities building stuff, a prolonged military campaign would therfore result in the mining becoming more profitable and the mines being upgraded and production increasing, combined with spending on military your economy would be experiencing a WAR TIME BOON!

Why a realistic economy model would be *%^&$%^ cool:
It would more perfectely simulate the real world than any other game, imagine a game where going to war results in an economic war time boon, grind your people into the dirt and have a palace full of gold. Sit upon a thriving, living economy that doesn't need you to manage it, pratically everything regulates itself (over time). Trade with your neighbour and both get richer, or exploit your neighbour and get rich at thier expense!
Become paranoid that everyone is out to ruin your economy, so set up an iron curtain! Take that, capitalistic pigs!
Flood the markets with goods and gain all the wealth in the world!
Frown as your farmers sell food to your enemy, so tax them some more to erode into their profit margins! No more holidays in the cities for you, greedy pigs!
TAX EVERYONE!
Dismayed at an economic recession (caused by excessive taxation), pour lots of money into building stuff to prop up the economy! Then got to war, gotta use those tanks for something, right?


So, what do you think? Would a full economic model be workable? More fun than a system where you do everything yourself? Do the increased interactions and possibilities make up for the lack of hands on and micromanagment? Is a full economic model a good idea OR is godzilla smaller than a rabbit?
Is money a good idea? Or should it be limited to simple supply/demand regulation?

Thats all from me, for now

[NeOmega]

I didn't quite understand everything, I got like probably 80% of it though. I think it would work well with my ideas in this post:
http://apolyton.net/forums/showthrea...hreadid=62233, at the bottom of the thread, the second suggestion about a sim city 2000 (although my idea was more like civ planet) type growth as opposed to civ's city radius growth.

All I know is be sure icons can be used, I want to see crates of food and stacks of cash, not just numbers.

[NeOmega]

Also, with respect to the multiple planet idea, this could make food an essential resource, beyond the level oil is today. Without food, mining planets could disappear in a year (in an extreme case of no food storage, and all food supplies cut off).
It could also have some less industrial but more agricultural factions/nations create a "food OPEC", and get away with charging the 400% iron curtain tariffs, and be an excellent political prelude to war. Possibly force industrial nations into an offensive, which could be advantageous to the defenders......

[Mark_Everson]

Hey Blake:

Just wanted to let you know that Clash of Civs already as a semi-real economy with some similarities to what you've outlined above. You can see what's in the spec by checking out the Economy link off the web page (URL in my sig). You can also see it in action in Demo 7, which you can try by going to the D7 thread at the top of the clash forum. Economic special goods like iron, salt, etc. are temporarily turned off in demo 7. If you want to see them in action, you can download demo 6. I'd like to hear what you think about the econ model if you check it out.

[Kirnwaffen]

I think it's workable, and may present some unique challenges and scenarios, but tell me, why does a farm become less efficient if it is upgraded?

[Blake]

Re: Clash economy model.
Yikes! It's long! I skimmed over it, from what I can tell it would be less self regulating and seems a fair bit more complicated - that would seem to be a natural nessecity of simulating thousands of years of human history, rather than just having a modern free market economy build up from nothing...
Didn't see anything on Supply, Demand and Money Supply but prehaps I didn't look hard enough. I do see Utility, Production functions... a fair few functions, not what I'd call a first principles model but given the changing enviroment I suppose they would be needed.

PCI looks interesting, as the StP inhabitants become richer their tastes will change, they wont be eating more food, but they will be desiring higher levels of luxuries...

From what I can see AI's will control the economy when the player doesn't want to? I have an intense dislike of AI's and prefer an economy can run without any higher intelligence at all, that would be the ideal solution because it removes potentional for MM without forcing an AI down players throats... prehaps you can make it work though.

So from what I can see, it's based on functions rather than supply and demand, workable but harder to balance. Probably more realistic given the context and given that the economy wont exactly be a free market for most of the game.

Re: NeOmega

Hmm, I think multiple worlds (atleast having multiple worlds being played on simultaneously) is outside the scope of StP. Altough it could certaintely be abstracted ie:
Have an empire screen that shows the other planets, and available trades, ie Earth has massive demand for food and will pay 20 credits/food crate. Sells hardware for 30 creds/crate.

Mining colonies that require 10 crates food/turn to be sent into orbit, and provide 20 crates metal/turn.

so on...

With respect to tarrifs and trade barriers, in the case of the Iron Curtain trade would actually be forbidden, which makes it 5 times more expensive to get goods out, when such a trade does happen you do NOT get a share of that profit, it is blackmarket dealing and the underground gets the money. (that'd be another nifty thing, in a too restricted market you get a thriving underground economy...)
Therefore a trade barrier costs are divided between tax which goes to your coffers, the underground economy, and transport costs (which are fed back into the economy - but not recieved by the producers.) Another possible way of having blackmarket, is the higher the taxes the more likely illegal trades will be made.

Something I didn't mention was transportation costs, when goods need to be transported some distance that costs money and makes the trade less attractive to producers. Road networks, highway networks, and magtube networks all act to descrease these costs - a magtube linked economy would be virtually frictionless.

As far as seeing crates on the main map, it would be reasonable to see food crates on the map if they need to be transported some distance (say over a border) but generally most trades will be completed inside one turn but they are fairly uninteresting trades anyway.

Icons could be useful as a graphical representation (ie click on a farm and it shows a stack of 5 food crates for production, and a stack of 7- Cash-wads which is the income)


Heres some more of my ideas:
The player zones tiles (which are somewhat large) as Agriculture or Mining, City's are either built or zoned (the tiles are large so cities will easily fit inside a single tile...), other zoing could include something for harvesting natural resources, like forests and Energy Generation (wind or solar).
On tiles the player has a few other things they can order built, like Hydro Power Plants and Boreholes which can co-habitat with other improvements but must be placed some distance apart.

There are a few facilities which are built inside cities themselves, and the population will happily build up market infrastruture that can be leased by the state for massive production levels.

How Mining could work:
You zone an area for Mining work and the Mining Mogouls get to work ripping up the land, they extract the resources that are most valuable and sell them where the demand is highest, different areas will have different concentrations which will also effect profitability. When mining operations are particullary profitable the mines will be upgraded increasing output. Mines will consume energy because they also do refining, the amount of energy consumption will depend on what exactly the mine is producing and how difficult it is to extract.
Types of mineables:
Ferrous metals (like Iron and Titanium), density varies quite widely. Used in units and population.
Aluminum: Relatively abudant but expensive to refine, used in many units, particullary those where lightness is important.
Uranium: Scarse and not used much by the market, can be used by Nuclear Power Plants which create Plutonium which can be used in nuclear weapons. Can not be traded cross border except in trade deals created by the leaders.
Gold, Silver and Platinum: High demand from richer market, rare, used in some tech units.
Construction Materials: Cheap and very abundant but high demand - something to do if the market is saturated with other products.
Oil: Can be consumed by power plants to create energy, and the market always seems to find countless uses for it. Could also be used by units. Rare.

Harvesting would be a more ecologically friendly way of extracting resources:
Primary is Construction Materials, but can also extract small amounts of metals and oil.
At higher upgrade levels sustainable methods are used, like replanting forests.
At higher tech levels extraction rates increase as plants are developed that can leech minerals from the soil, and biocrops are developed for synthetic fossil fuels, these will be grown when demand is high (they are, after all, quite expensive compared to ripping it out the ground).

Mineral stocks may deplete.

Energy Zoning:
You can zone areas for renewable power, this will be wind, solar or hydro (?), when energy demands increase energy output will be upgraded, as with farms. Energy will have zero cost distance distribution and little stockpilability.
It is quite possible that building major powerplants will be the job of the state, because they will have ecological impact and other side effects

Demand will be calculated with usage / stockpile calculations. It will be possible to drive up demand by buying resources and stockpiling them at your capital, this would be useful if you are preparing for a massive military buildup and know the current levels of mine production are too low. Energy will probably also be calculated using stockpile, altough strictly speaking energy cant be stockpiled it will simplify the calculations. If labour is to be traded then it would be treated simiallery - created by cities and "sold" to the producers, including across borders. Distance costs would be high for labour (people like to work close to home).

another reply comes in while I'm replying...

I think it's workable, and may present some unique challenges and scenarios, but tell me, why does a farm become less efficient if it is upgraded?

I mean in terms of diminshing returns. A farm might cost 1000 to build and produce 10, then cost 1000 to upgrade and produce +9, total 19, it would be more effecient to build a second farm (same cost, produce 20). The reason for diminishing returns is that the new fields would be on poorer lands (having used the best lands first), or using more capital/labor intensive techniques to get more production out of the same land. It also helps balance...

[Mark_Everson]

Hi Blake, I don't want to hijack your thread, so just a few brief responses / corrections

Originally posted by Blake
(snip) from what I can tell it would be less self regulating and seems a fair bit more complicated

Its quite self-regulating, perhaps even Too self-regulating. (That we need to address in further playtesting, though I think we're ok.) The economy is a bit complicated but essentially the two key fuctions you menion Utility (= Demand) and Production (= Supply) mean things can evolve smoothly and sensibly without those huge discontinuous jumps you get in civ/AC type economies. Your Supply and Demand are functions too, just very simple functions. And because your functions are simple and can give bad behavior in some regimes you need special rules to give you diminishing returns as in your post above. The Clash Production function takes care of all that. YMMV

From what I can see AI's will control the economy when the player doesn't want to? I have an intense dislike of AI's and prefer an economy can run without any higher intelligence at all, that would be the ideal solution because it removes potentional for MM without forcing an AI down players throats... prehaps you can make it work though.

Hmmm... don't know how you got that impression. The economy Does run without any higher intelligence. The people themselves have needs for things (Utility) and try their best to get what they want. However, if the player doesn't want to specify what they want to build then Something has to do it, and thats where the AI and MM-reduction come in. The utility concept also makes a real trading system in Clash naturally flow from the other economic specs, rather than being some artificially tacked-on bit.

Good luck with your model!

[DeathByTheSword]

cool idea but if you make food a consumer good?! how will cities grow? only that 5 %? that would be kinda wack because not every city grow with the sam amount?! for the rest i would be cool. maybe you can take building facitilies also out of the hand of the player by letting buildingcompanies build them and warfactories build tanks and equiment for the army....

[DeathByTheSword]

with this you could also put in that as an atrocity you could send infected food to the enemy produced on special governmentfarms :devil:

but more real now. you could make the difference between government-run and citizen-run farms and tile improvement. the citizens one will produce more(effective) but cost more/upkeep bigger or something(profit)
and goverment-run will produce less(ineffective UNP-style)/ but upkeep les too (no profit needed) this could be greatly expanded so that military bases (bunkers/radar/defence-weaponary/etcetc) would only need food from the government-run thingy orso or that during war and/or we get invaded that citizens-run facilities will produce less and government-run are less harmed. and government mines that wouldnt be effected by demand/supply so that you could get you uranium even do you forbid nuclear power or that you could get steel when during war the prizes go to high......

what ya think

[Blake]

Okay, thanks for the correction Mark, btw I got the AI idea from:

You can't have a civilization without an economy! And Clash will provide an extremely detailed and realistic one. The powerful AI will handle all the details or it can be micromanaged to the nth degree. Your choice!

It's right below "Model Description"


Population Growth:
The basic growth will be around 5%, however there will also be immigration which will mean that small cities will tend to grow faster and older cities slower (relatively speaking). The assumption is that people everywhere breed at a pretty steady rate (they do after all have a large amount of space to fill) however some locations are more desirable than others so population will flow from less desirable to more desirable place.

This means that population growth wont really depend on the quality of the land, which will tend to even things out between players. It is possible that population growth will be modifiable for factions or by SE, the increments are likely to be quite small, +0.25% or +0.5%

Overall compared to Civ2 or SMAC the population growth will be slower in the early years, but faster in the later years, also later in the game new cities will ramp up a lot faster thanks to immigration.

but more real now. you could make the difference between government-run and citizen-run farms and tile improvement. the citizens one will produce more(effective) but cost more/upkeep bigger or something(profit)

I'm not particullary interested in realism for the sake of realism, and my crusade against micromanagment comes first in model design .
Earlier in the design process we covered "State" and "Market" infrastructure, state infrastructure is fully controlled by you (the state) while market Infrastructure is managed by citizens and you get taxation income and in some cases can buy production.

It is likely that some facilities will be state, and other market, but on the whole their wont be identical versions because that leads to micromanagment. It may be possible for example to build Factories that are owned by the state, they provide guaranteed production for you and create employment for local population. It is possible you'll be able to sell unused factory cycles back to the market if you have nothing to build (this will be something like wealth or public works or somesuch...)

[Gateway103]

Good idea Blake, glad to see that you have also incorporated many of the economics ideas (ok, many of them yours, but anyway) on the FACF.

This model also introduces some interesting possibilities. For example, ordinances such as governmental relief in case of natural and/or artificial disaters, governmental funding program that increases the rate of upgrad of production facilities at the expense of your treasury, policies to off to buy a the local production at higher price (say 10%) to disencourage export (in addition to more other export restriction policies) and more.

Keep up the good work.

-Gateway103

[Blake]

Hmmm, yes, to a certain extent any spending will help boost the economy (altough remembering that the money you are spending came from the economy in the form of taxes, it kinda evens out...).

Another useful thing could be subsidies as to make your farmers competitive with the neighbours farmers. Say that your neighbour has much better farms and is exporting a lot of food. That drives down demand in your faction and causes your farms to be less profitable and not upgrade so often. Now if this neighbour suddenly closes down all trade your faction would suddenly be starving until your farms can be upgraded enough to supply the food, or you import food from someone else, or you pay the neighbour to re-open trade channels

The subsidy acts to make farming more profitable so the farmers will produce more and upgrade more often, this will generally be less economical than importing but you arent left reliant on any other faction. Another way of achieving the same thing is putting a steep tarrif on imported food (altough this would result in a period of hunger, unless such a policy was used from the start)
Subsidies could also be used to flood your neighbour with cheap food, and put them in such a dependency as described earlier. In this case you subsidise your Farms and remove all trade barriers on your end - however there is nothing to stop the neighbour putting trade tarrifs and such carryon is observed between nations on Earth (US claims NZ farmers are dumping NZ Lamb in US at below cost, US increases tarrifs on NZ lamb)

On FACF forums there was the suggestion of having state economies as well (ie communist or planned) altough I believe with a system of subsidies, taxes and trade barriers a player could set up such a planned economy.
- Shelter your economy by putting steep tarrifs on all imports.
- Subsidise industries to improve output or tax them to decrease output.
- If you want to stop exporting too (for some reason... exporting increases wealth in your faction...) then set up extra trade barriers.
The net effect is the same - you can have and manage your Planned economy, but it doesn't require a whole seperate model.

For increased flexibility it should be possible to set subsidies/Tarrifs/taxes for each resource.
Here a trade adviser could actually come in very useful, particullary for players not familliar with macroeconomics I'm against advisers which can only give drivel but a trade adviser could be made that gives useful advice, ie:
Random advice for a potentionally bad situation
"Sir, we are importing 60% of our food, you should consider import tarrifs or subsidising our farmers to reduce our dependencies on others"
Advice on a particular resource

Our metal production is low.
To increase metal production:
- Reduce taxes on metal production.
- Buy some metal to increase our stockpiles and prop up the mining industry.
- Build some units to increase demand for metal.
- Subsidise metal production.

However note that in a game with all newbies (ie no experienced market manipulators) just leaving everything as defaults will give a fairly optimal outcome, as thats how Free Markets tend to work. At expert level manipulating the market will be quite essential to victory, particullary when it comes to avoiding being exploited by other players.

Note: The easiest way to avoid exploitation is to put steep tariffs on all imports, altough note that such a closed economy loses out on possible gains from trade.

I'm not sure if it would be useful to set tariffs per-resource per-player, because it ultimately wouldn't achieve much, if you set tarrifs for just one players imports, that players goods could still go through another player and come in at the no-tarrifs rate (I wont go into the full details of how that works, it's more a principle of macroeconomics).
A good way to have it IMO would be to allow setting a general tax on imports from another player, that applies to all goods from that player, or setting full scale embargo.


Now that I've had more time to examine the implications in depth, some more really cool things about this model is:
- Allows for full-scale economic warfare, allowing a non military orientated way to play.
- Allows fine tuning of your factions production from a single screen, with a flick of a slider you could emphasis food production, encourage importing, increase income.
- It builds a strong dependence between long-term allies, if both have open market policies then it is likely the factions will become dependent on each other for atleast some of their resources (80% of A's food is imported from B, 70% of B's metal is imported from A) This would make backstabbing a long-term ally much more expensive and encourage the formation of stable alliances. Note that if two players are only allied for a short period the markets will remain relatively independent - backstabbing will become increasingly more painfull over time.

[Vultur]

I don't agree with Blake growth model, because it doesn't consider "starting conditions": each faction start with a small group of 10.000 colonizers that land on the surface of an alien planet.
If your first base growth at 5% rate your base will take 18 years to have the population necessary to found an other base: too much. In addition if you consider a big metropolis (10 milions of people) you have after one year 500.000 more people, that can found 50 bases!
The risk with this model is to have a starting of game really boring and a continous famine problems in mid-late game.

Solution 1: Civ-like growth
Ok, it's totally unrealistic, but it's simple and well known from Civ-like games.

Solution 2: Ultra-realistic growth
It's possible to have a complex model that devide population in function of their age, stimating how many children are born and how many oldies has "becomed one with all the people"
Cons:lot of coding, huge memory wasting

Solution 3: Probabilistic growth
Not a lot realistic, but efficient.
First step:
We have 3 groups: Children, Adults and Oldies. Each group has these parameters: Min Age, Max Age, Num of people, Average Age.

Second step:
Each turn all groups' parameters are regulated by these formulas:
C_Num_In=f(A_Aa)*G%
where C_Num_In is the number of children born and A_Aa is the Adult Average Age.

Next_Group_Num_In=Num/Range*(1-(MaxAge+MinAge-Aa*2)/Range)
where Range=MaxAge-MinAge
This formula can be applied both for Children->Adult and Adult->Old.

O_Num_Out=f(O_Aa)*D%
where O_Num_Out is the number of oldies retired because of the age.

NOTE: an high death rate (D%) can be caused by bad health condition, famine or war and can provoke emigration/rioting.

Third Step:
This formula calculate the new average age for each group of people:
Aa=((Aa+1)*(Num-Num_Out)+MinAge*Num_In)/(Num-Num_Out+Num_In)
where Num_Out is the number of poeple that leave the group and Num_In is the number of people that enter in the group.

Fourth Step:
this is the formula to close the cicle:
[i]Num+=Num_In-Num_Out[i]
that must be applied on all groups

This method that seems pretty complicated can be "totally" masked to player.
I've tryed to use it in a couple of experiment and give pretty good results.
The thing that we must care about more are formulas for Growth and Death Rates.

Any comment/suggestion is welcome.

[Blake]

I dont see how exactly that fix's the percieved problem.
It is more realistic, which means you get even slower early growth because there will be primarly children grown for the first 16-20 years, this results in diminshing resources in those early years and a resource boom from 20-40 years.
This unstable resource output is why I think it's better to just use a stable growth of 5% and forget about age groups for the sake of gameplay. (such a growth model may be useful for a hardcore simulation of planetary colonisation, but not a strategy game)

Early game

Consider: In SMAC on poor terrain it takes about 18 years to grow from 1-2 then about 30 years from 2-3 (on the worst possible terrain that allows growth at all...)
Factions will start with 20000 population or more (fast start would be like 100000)

20000 grows another 10000 in 8.5 years which isn't too slow.
Bases will not require a full 10000 to found, they can be founded with a token population and immmigration will fill them.

Mid-game

In SMAC when pop-booming population growth %age ranges from 33% at size 3 to 8% at size 13 to 3% at size 30...
Considering rampant ICS employed by SMAC'ers and that StP will have less and larger bases mid-game growth will not be faster, but it will be more steady thanks to the elimination of hard pop caps and pop-booming.

Late game

In the late game crowding effects will come into play, particullary as the world population approaches the billions, the absolutele maximum population will be limited to around 10 billion (limited by the overcrowding factor and the amount of food that can be grown)
It will take around 300 years to reach that population size, which would be plenty long enough for a game... I expect most games will be over in the 100-150 years range.

The main difference is that while in SMAC populations stagment in the late game, they will boom in StP and resources will continue to grow at a phenominal rate.
* Note unhappiness due to population size will be on the whole eliminated, because it would be essentially unmanagable, and historically larger cities are not unhappier.

[Vultur]

Originally posted by Blake
I dont see how exactly that fix's the percieved problem.

The fix is in these formulas:
C_Num_In=f(A_Aa)*G%
Where f is a function of existing population (avoid risk of pop stagnation/eccessive overcrowing), of general level of education (more civilized nations has a near-zero growth while less advanced ones has pop-booming problems) and the Adult's Average Age.

and

O_Num_Out=g(O_Aa)*D%
Where g is a function of health value (modified by overcrowing, pollution, famine, wars, plagues...) and the Oldies' Average Age.

Originally posted by Blake
* Note unhappiness due to population size will be on the whole eliminated, because it would be essentially unmanagable, and historically larger cities are not unhappier.

I've never said that larger city is unhappier than a little one, but when your population growth there are more chance to creating Drones, that are not unhappy , but only with a low level of education, so less efficients.
In case of unemployement the Drones will be the first ones to lose their work, and, only if unemployed, become unhappy.
There can be other reasons of unhappiness, like famine, war, few health, overcrowing...