Pop growth - what about decrease?

[CyberianK]

I think its better to be Xenophile and go for multiple species so that you can colonize 3-4 planets immediately and start an early growth boost. Also Xeno-compatibility FTW!

Yeah it might be better but I experienced theres often Migration to external Empires early game and also I want increased growth from day 1 on when I have not met anyone to have early snowballing. Plus I can Enslave all the pops I meet like for examples conquering MedievalCivs with few armies. Influence decrease for starbases is also very great and Migration is a bit of a mess but I will also try it just for giggles.

 

[Flame13223]

Oh yeah

Yeah it might be better but I experienced theres often Migration to external Empires early game and also I want increased growth from day 1 on when I have not met anyone to have early snowballing. Plus I can Enslave all the pops I meet like for examples conquering MedievalCivs with few armies. Influence decrease for starbases is also very great and Migration is a bit of a mess but I will also try it just for giggles.

Oh yeah I conquer primitives as xenophiles in the early game and dont even use Migration treaties until after I know I have a bigger pull than push.

 

[Kinkness]

Well if you want to bring in the real world, population is expected to stabilize soon at around 10 billion (depending on which model), and many countries already have low population growth. In fact some are already in the negative. The only reason western countries are growing in population is because of immigration.

So how would realistic population growth be in Stellaris? In 2200, Earth would have already stabilized, if not be decreasing. Please mind that in reality there probably wouldn't be many natural resources left as well, but let's ignore that for now. Earth's population would be the only growth factor for new worlds until either pro-child indoctrinment, forced childbirths or lab-grown children or clones became commonplace.

Let's just say machines and hive minds would be OP.

Hmm that's interesting.. I thought the reason for certain countries negative growth was only because of immigration, people leaving more than people are being born, but the whole worlds populations, and will always forever continue to grow.

I seriously doubt the world will just suddenly start having more people dieing than being born.

This of course isn't taking into account of technology allowing people to live longer which also would push this number up.

 

[Calvax]

If you want to compare this to the real world, it actually simulates exactly how it is irl. While yes people die of sickness, old age, etc. The population of the world is slowly and steadily growing. Just like it does in Stellaris, and since in Stellaris you're looking at the "big picture" Thats exactly what its doing.

Whilst true the rate at which the population is growing is decreasing due to the more economically advanced regions undergoing demographic transitions. Many wealthy nations only have positive growth due to immigration. There's a myriad of reasons for this that don't need to be simulated in stellaris (and wouldn't be fun to) but the idea of an advanced society naturally or with some effort trending towards stable growth isn't unreasonable.

 

[Kinkness]

Whilst true the rate at which the population is growing is decreasing due to the more economically advanced regions undergoing demographic transitions. Many wealthy nations only have positive growth due to immigration. There's a myriad of reasons for this that don't need to be simulated in stellaris (and wouldn't be fun to) but the idea of an advanced society naturally or with some effort trending towards stable growth isn't unreasonable.

It's also taking into consideration the time frame of Stellaris. While right now you and zukodark may be correct in what its like currently in 2018.. That doesn't mean in another 500 to a thousand years we won't have anything but over abundant growth everywhere due to cheap and easy health technology to extend your life by a few hundred years. Which is why I say the system currently in place for STellaris with only growth for the most part, and wars being the huge killer makes sense. (From a current, and possible future sci fi understanding)

 

[zukodark]

Hmm that's interesting.. I thought the reason for certain countries negative growth was only because of immigration, people leaving more than people are being born, but the whole worlds populations, and will always forever continue to grow.

I seriously doubt the world will just suddenly start having more people dieing than being born.

This of course isn't taking into account of technology allowing people to live longer which also would push this number up.

I think you are looking at this the wrong way. For population growth to be positive, each woman needs to give birth to 2,1 children. Yes, that means more women needs to get 3 or more children than 1 or 0 children. Since modernized countries tend to have a lot single women, as well as couples who marries late in life (you aren't going to get a lot of children after 40), negative population growth is natural. And it seems like this is a trend that happens to every country as it modernizes (after decades of rapid population growth).

For example Niger has the highest total fertility rate, at 7,2 children per woman. Korea is down at 1,2, Japan (which has negative total growth due to low immigration) is at 1,4 and Germany is at 1,5. US and UK are both 1,8 which still is negative.

It's also taking into consideration the time frame of Stellaris. While right now you and zukodark may be correct in what its like currently in 2018.. That doesn't mean in another 500 to a thousand years we won't have anything but over abundant growth everywhere due to cheap and easy health technology to extend your life by a few hundred years. Which is why I say the system currently in place for STellaris with only growth for the most part, and wars being the huge killer makes sense. (From a current, and possible future sci fi understanding)

The issue with that statement is that leader age is represented in Stellaris but has no impact on population growth. Anyways, I mentioned cloning, technology and robots as a possibility for higher population growth, as well as other possible reasons. In general we could say Stellaris might have experienced an unknown stage in the growth rate evolution, where a counterculture around actually making children become a thing.

Anyways, it is a game, doesn't need to be realistic.

 

[djvandebrake]

Posted this in another thread, thought I'd repost here to back up what zukodark was saying. If it were not for immigration, many countries in the developed world would actually be seeing shrinking population.

https://en.wikipedia.org/wiki/Sub-replacement_fertility

In fact, Japan is approaching a demographic bomb because their immigration is so low that in the coming years they won't have enough workers to provide for all the elderly they have.

 

[Sarmatian]

I think you are looking at this the wrong way. For population growth to be positive, each woman needs to give birth to 2,1 children. Yes, that means more women needs to get 3 or more children than 1 or 0 children. Since modernized countries tend to have a lot single women, as well as couples who marries late in life (you aren't going to get a lot of children after 40), negative population growth is natural. And it seems like this is a trend that happens to every country as it modernizes (after decades of rapid population growth).

For example Niger has the highest total fertility rate, at 7,2 children per woman. Korea is down at 1,2, Japan (which has negative total growth due to low immigration) is at 1,4 and Germany is at 1,5. US and UK are both 1,8 which still is negative.


The issue with that statement is that leader age is represented in Stellaris but has no impact on population growth. Anyways, I mentioned cloning, technology and robots as a possibility for higher population growth, as well as other possible reasons. In general we could say Stellaris might have experienced an unknown stage in the growth rate evolution, where a counterculture around actually making children become a thing.

Anyways, it is a game, doesn't need to be realistic.

I think you're looking at it the wrong way. Population can increase even with less than 2 children per woman. Especially if were talking about a future setting where people can live a 100 or 200 years.

Couple A has 1 child when they're 30.
Their Child has 2 children by the time he/she is 30.
of their 2 children, one has 1 child, the other 2, when they both reach 30 years of age.

That is very well below 2 children on average treshold, yet, it couple A is still alive in their 90's, it's a significant population increase. From 2 persons, 60 years after their single child was born, their is now 6 descendants in total, and looking just at Couple A, there's a net gain of 300%

 

[djvandebrake]

I think you're looking at it the wrong way. Population can increase even with less than 2 children per woman. Especially if were talking about a future setting where people can live a 100 or 200 years.

Couple A has 1 child when they're 30.
Their Child has 2 children by the time he/she is 30.
of their 2 children, one has 1 child, the other 2, when they both reach 30 years of age.

That is very well below 2 children on average treshold, yet, it couple A is still alive in their 90's, it's a significant population increase. From 2 persons, 60 years after their single child was born, their is now 6 descendants in total, and looking just at Couple A, there's a net gain of 300%

I think you missed something here. The children will have spouses, and those antecedents. So yes, couple A will have three great-grandkids... but those great-grandchildren will have more than three great-grandparents. When the oldest generation dies, there are fewer grandkids around to replace them.

 

[Bezborg]

I agree that a population of a world should stabilize around a number that is defined by a planet’s total capacity (depending on development of course)...

Infinite pop growth (however slow) eventually consuming the entire universe with overpopulation should not be in the game.

No matter how gloriously and beautifully nihilist that sounds

 

[Sarmatian]

I think you missed something here. The children will have spouses, and those antecedents. So yes, couple A will have three great-grandkids... but those great-grandchildren will have more than three great-grandparents. When the oldest generation dies, there are fewer grandkids around to replace them.

No, I didn't. Do it with 2 pairs, you'll reach same conclusion. Population will become older on average, that is true, but in pure numbers it will rise... In China, during one child policy, population actually increased. In 1960's, there was 2 child policy - China's population increased from almost 0.7 billion to about 1 billion in 1979 when when one child policy was introduced. From 1979 to 2015 (when it was abolished), China's population increased from 1 billion to 1.4 billion.

It becomes even more evident with longer average life expectancy. In Stellaris life expectancies can be rather long, so it wouldn't be uncommon for pops to be alive when they have grand-grand-grand-grandchildren.

 

[Kinkness]

I agree that a population of a world should stabilize around a number that is defined by a planet’s total capacity (depending on development of course)...

Infinite pop growth (however slow) eventually consuming the entire universe with overpopulation should not be in the game.

No matter how gloriously and beautifully nihilist that sounds

This, I agree with.

 

[djvandebrake]

No, I didn't. Do it with 2 pairs, you'll reach same conclusion. Population will become older on average, that is true, but in pure numbers it will rise... In China, during one child policy, population actually increased. In 1960's, there was 2 child policy - China's population increased from almost 0.7 billion to about 1 billion in 1979 when when one child policy was introduced. From 1979 to 2015 (when it was abolished), China's population increased from 1 billion to 1.4 billion.

It becomes even more evident with longer average life expectancy. In Stellaris life expectancies can be rather long, so it wouldn't be uncommon for pops to be alive when they have grand-grand-grand-grandchildren.

Okay, let's consider a population where everyone reproduces at 20 years old, and dies at 80 years old. Assume an initial population of 100 20-yr. old people in the year 2000 - 50 men and 50 women. We will assume each couple has 1 or 2 children, perfectly balanced so the average fertility rate is 1.5. In case of decimal numbers we will round up.

Year 2000: 100 people initially
- 100 age 20.
- 75 children born.
Year 2020: 175 people initially
- 100 are 40.
- 75 are 20.
- 57 children are born.
Year 2040: 232 people initially
- 100 are 60.
- 75 are 40.
- 57 are 20.
- 43 children are born.
Year 2060: 275 people initially
- 100 are 80 - they die off.
- 75 are 60.
- 57 are 40.
- 43 are 20.
- 33 children are born.
Year 2080: 208 people initially
- 75 are 80 - they die off.
- 57 are 60.
- 43 are 40.
- 33 are 20.
- 25 children are born.
Year 2100: 158 people initially
- 57 are 80 - they die off.
- 43 are 80.
- 33 are 60.
- 25 are 20.
- 19 children are born.

Do you see what is happening? The initial population surges, but as the oldest generations die off it starts dropping again. You will find this same effect no matter when people start giving birth or how long they live - unless people are immortal, they will eventually die, and if they have left behind fewer offspring than is required to produce children, the population will decline. In a population with sexual reproduction, that number is 2, so a fertility rate below 2 cannot grow once older generations begin to die.

 

[Maal]

New resource : Manpower !
Decision on planets to convert 1 workable pop into 100 manpower.

Colony ships cost 100 manpower (200 with the tradition that increase new colonies size).
Each combat ship cost manpower, the bigger the ship the more manpower.
Outpost and other space stations also cost manpower.

Send your entire people to die in the empty void!

 

[zukodark]

No, I didn't. Do it with 2 pairs, you'll reach same conclusion. Population will become older on average, that is true, but in pure numbers it will rise... In China, during one child policy, population actually increased. In 1960's, there was 2 child policy - China's population increased from almost 0.7 billion to about 1 billion in 1979 when when one child policy was introduced. From 1979 to 2015 (when it was abolished), China's population increased from 1 billion to 1.4 billion.

It becomes even more evident with longer average life expectancy. In Stellaris life expectancies can be rather long, so it wouldn't be uncommon for pops to be alive when they have grand-grand-grand-grandchildren.

The problem here is that in Stellaris, life expectancy has no effect on pop growth. An empire which live with -10 life expectancy trait with no life bonuses grows as quickly as an equivalent empire with venerable trait, harmony and which is cybernetic. Really doesn't add up.

My question is if age-of-marriage is becoming higher and higher, wouldn't it increase even more by 2200? And probably would be higher when people life older, why not enjoy the single life without children until 50 if you're going to live to 200? Technology makes fertility last much longer at the same time if we factor it in, so I doubt population would grow very much anyways.

 

[zukodark]

As for how I'd like pop growth to work ingame: Make it based on total population instead of granting as much per-planet. I'd still keep the immediate boost to pop growth, but only for fledging colonies. It's not that strange to think people would have more children when populating an entirely new planet. However that "colonization fervor" bonus should go away eventually.

How it would work in effect:
Game start:
Capital - high growth: population

After colonizing second planet:
Capital - mediocre growth: population, emigration
Colony - moderate growth: colonization fervor bonus, immigration

After second planet has ~10 pops:
Capital - moderate growth: population, emigration
Colony - high growth: population, immigration

After second planet has grown:
Capital - high growth: population
Colony - high growth: population

 

[The Boz]

There are options to limit pop growth on a per planet basis right now but they're useless. More pops is always better than fewer pops. There's no situation where an empire with more pops will be worse off than an empire with less pops. Pops are the ultimate indicator of economic power in 2.2

Lategame unemployed and homeless pops are a HUGE burden on your economy, especially if playing tall.

 

[CyberianK]

Lategame unemployed and homeless pops are a HUGE burden on your economy, especially if playing tall.

Lategame you can just create a few Ecowhatsitcalledpolis. Or build artificial planets. Or conquer enemy territory.

If you are running out of planets you are either playing badly or intentionally don't want to win the game.

 

[Flame13223]

Lategame unemployed and homeless pops are a HUGE burden on your economy, especially if playing tall.

So just resettle them. You can do it right now with both Authoritarian and Egalitarians.

 

[#Tukuro]

Conclusion:
Better having a fertility rate instead of a persistent growth rate.

What do you think? Do I overlook something?

Isn't this already represented by pops growing at the same rate, regardless of population size?
At start - assuming you start with 24 pops and your default growth rate is 3 - your homeworld's population will grow at only 1.5%/y.
By the time your population hits >80, relative growth has plummeted to just 0.45%/y.

I find the current system easier to understand than the previous one, which did take total population into account. Linear growth makes it easier to predict what your population will be in the future.
In contrast, the old system had several (opaque - assuming you didn't check the scripts) modifiers attached to it, including food surplus, split growth, habitability, etc. So if you wanted to extrapolate population growth, you sort of had to grab a calculator and take into account diminishing returns...