Why do planets build pops? Why don't pops build pops?

[laptor]

This is perhaps the most counter-intuitive part of the game, and where the simulation parts hardest from reality. Each pop, if properly fed and housed, should generate its own offspring. Limiting pop growth to one at a time per planet makes no sense.

It warps the meta towards the current "grab every planet you can regardless of quality" because your growth is limited to one pop per planet. In reality, 20 billion people on one really nice planet would reproduce faster than 1 billion people on twenty crappy planets. But in stellaris that's the furthest thing from the truth.

True, and pop growth mechanic needs to be tweaked. But in terms of balance (or gameplay) the steady growth rate may be better.

 

[anamiac]

I would just have population growth rate be determined by the maximum of available housing and population.

Population_growth_rate = 3 + max(avail_housing, population) * 0.1

 

[strangebloke]

TBH, all they really need are some dynamic planetary growth modifiers.

IE, if the planet has really high stability, you get a +X% to growth, since historically birth rates plummeted in times of social unrest. If you have Y pops on a planet you get a +(Y/Z)% bonus to growth since obviously having more pops means more new pops. If you're missing housing/amenities, you get significant -Q% debuffs to growth. If a pop has low habitability, they get a malus to growth. Obviously you have to combine this with the 2.2.5 changes such that relatively low habilitability races grow less often. So if you've only low-habitability pops on a world, growth will be slow, but if you've several pops, one of which has high hab, it will grow relatively quickly.

The growth slowdown that's currently happening on earth is a product of higher education and the subsequent drop of utility of child labor. In places where child/uneducated labor is still valuable, the population is still booming. There's not really a good way of showing this, since Stellaris has as its baseline the creation of a massive, galactic economy which would completely throw all dynamics out of whack.

Anyway, with a few modifiers like this, we'd be able to see the "A Few Big Planets" playthrough finally gain some traction, I think.

 

[Zergor]

I would just have population growth rate be determined by the maximum of available housing and population.

Population_growth_rate = 3 + max(avail_housing, population) * 0.1

This doesn't solve the problem. Pop growth would still be determined by the planet except that bigger planets would grow pops faster.
Also there is no such thing as max housing. Housing is purely building and district dependant. And tech can also increase it.

 

[anamiac]

Also there is no such thing as max housing. Housing is purely building and district dependant. And tech can also increase it.

You do not understand me, and I also made a mistake. I meant to say min instead of max. What I'm saying is that if the unused housing is higher than the population, then we use the population. Otherwise, if there's more population than unused housing, then we use the unused housing rule. So if I've got a planet with 80 pops and 20 unused housing, then the formula becomes:
Population_growth_rate = 3 + min(avail_housing, population) * 0.1
Population_growth_rate = 3 + min(20, 80) * 0.1
Population_growth_rate = 3 + 20 * 0.1
Population_growth_rate = 5

 

[Four eyed fish]

Growth rate as an empire mechanic mediated by planetary modifiers may help tall play as tall and wide would both have the same growth potential.

 

[Nussor]

There are too many mechanical problems with creating a realistic growth model.

Pop growth is exponential IRL and world population doubles every 50 years. Exponential growth would break any game at some point and would break us too, if not for the things that keep us from having offspring: culture, wealth and contraceptives. But the things that keep pop growth in check are equally problematic. How do you balance your need for labour against people only making 1.x babies per couple? How do you factor in automatisation? How do you fit in this mess in an exponential growth model?

And now imagine having a hive mind insect species being able to double its population AT WILL.

 

[strangebloke]

Growth rate as an empire mechanic mediated by planetary modifiers may help tall play as tall and wide would both have the same growth potential.

This would work, except that it's kinda weird how robots work.

 

[AlanC9]

Pop growth is exponential IRL and world population doubles every 50 years..

Well, it's exponential until it isn't. In theory, you could design a system where economic incentives on more filled-up planets end up naturally capping growth, while frontier planets grow exponentially. Sort of a more extreme version of what we have now.

 

[anamiac]

Well, it's exponential until it isn't. In theory, you could design a system where economic incentives on more filled-up planets end up naturally capping growth, while frontier planets grow exponentially. Sort of a more extreme version of what we have now.

How are you defining this word 'Exponential'? You keep using that word, I don't think it means what you think it means. Exponential and Linear are mathematical terms. When related to population growth, linear growth is constant, regardless of population. Exponential populations means that it's more useful to talk about growth as a percentage of existing population.

For instance, New York City has a population of 8.6 million and gained 447,565 residents or 5.5% over the course of 7 years. If we believe human beings growth rates are linear then we can determine population growth as 63,937 per year and we estimate the 1919 population as 2.2 million. However as we go further back it gets ridiculous with NY having 1 person in 1884 but that person having grown to 64k people in 1885. The reason why the linear method fails is because it's unrealistic.

Suppose we take the exponent approach estimate how many people there were at a given date. If we extrapolate that New York gains .78% population every year then 100 years ago it had 2.75 million people. This is not only closer than the linear estimate (actual 1920 population was 5.6 million), but it allows us to go back in time further than the linear example. It allows us to guess population 200, 300, 400 years ago. It only fails insofar as the the exponent (the percentage) changes over time. But nobody said that exponential growth as defined mathematically means a constant exponent, or even a big one. The population dip in china was exponential, not linear. It just had an exponent that was smaller than 1. 98% and 115% are both exponential interest rates, even though the latter one will grow your money very quickly and the former will see your assets slowly shrivel and die.

So yes, human beings do grow exponentially, exactly like bacteria and any other lifeform. Do you know that you have several pounds of bacteria in your body at any given time? But you're not about to explode tomorrow. It's all growing exponentially, but that exponent is very close to 1. This is the most natural, most normal state of bacteria. Of course, if you stick it in an unnatural environment where there are no predators, no pesky white blood cells to enforce the law, and an unlimited amount of food, then it's going to grow much faster. Human beings could also grow much faster without limitations than we currently do. I knew a man with one wife and 16 surviving children. And yes, I realize that isn't socially normal in this day and age, but social norms are another one of those limiting factors I'm referring to.

 

[AlanC9]

Good points; lots of sloppy language in this thread.

Hey, how come nobody says "geometric progression" anymore?