Terra Invicta – What Regulates Population Growth?

Explanation of Population Growth

Population growth is calculated by region, and as far as I know there are six factors:

1. The Nation that owns the region.

Each nation has a base population growth rate, reflecting the recent history of that nation. China for example, has -1% base pop growth because of its one-child policy.

2. The GDPPC of the region.

(This can differ from that nation’s GDPPC).

Richer regions attract more immigrants, increasing population growth by 1% for every 300k GDPPC.

3. The Education/Government of the region.

Lower government and education scores prevent access to birth control and so increase the pop growth rate. The pop growth from this factor is calculated as follows:

100% * Min(0.035, Max(10 - Govt,0)^2 / 1000, Max(10 - Edu,0)^2 / 1000).

4. The Cohesion and Development of the region.

A region is developed if it has at least two regions (or contains a special merged region) and its education + government + GDPPC/4000 is at least 25.

Developed regions gain a pop growth bonus for having moderate cohesion, representing a diverse and non-segregated population. This pop growth bonus is calculated as follows:

100% * (5 - |5 - Cohesion|) / 7.

5. The Xenoforming in the region.

Dangerous alien lifeforms increase the death rate of people living in the region.

If a region contains xenoflora, then population growth is decreased by max(0.375%, xenoflora growth % / 2).

Xenoflora growth % is how far along the xenoflora is to spawning a megafauna.

6. The nukes used on the region.

Nuclear fallout contaminates a region permanently, causing deaths and fatal birth defects and so reducing population growth by 4% ADDITIVE for every nuke previously dropped on the region.

These six factors are simply summed up.

Then if the result is positive, it is multiplied by 0.95. Otherwise if the result is less than -95%, it is replaced by -95%.

The final result is the annual population growth rate of the region.

There is also a small amount of randomness added in when calculating how many people a region actually gains/loses each month.