What does the ethics divergence value actually mean?

Question

How should the ethics divergence value be interpreted? I understand that negative values means that the pop is more likely to change their ethics to be in line with the empire's values (presumably with larger negative values meaning faster convergence), but what exactly does a smaller or larger positive value mean? What does a value of 0 do? If I want a pop to change their ethics, particularly without caring about what they change it to, how should I try to affect ethics divergence?

Background: My game had a fanatical xenophobe empire going around conquering their neighbors and exterminating their populace. I didn't like this very much, so I declared war and took over a bunch of their worlds. Being fanatical xenophobes, the populace isn't particularly appreciative of my more "enlightened" rule, with a -40% Alien Overlords happiness modifier. This destroys their productivity and makes them join rebellious factions. Getting rid of their xenophobia is sufficient to make them happy and productive citizens again.

As such, I'm trying to get them to change their ways. I don't particularly care what they change to, just that they're no longer fanatically xenophobic. These planets are far from my homeworld, and the populace is "outraged", so the ethics divergence value is higher than the reeducation edict can handle. Furthermore, I don't particularly want them to adopt my ethics either, given that my empire is also xenophobic (though this lesser xenophobia is much more manageable than the current Fanatic, so it's still acceptable). To make them change, do I want to raise or lower ethics divergence?

Answer 1

Ethics divergence is either positive or negative.

If it is positive, it will push your pops' ethics further from your empire's. If it is negative, it will push their ethics toward your empire's. This has been demonstrated in another answer here and the Stellaris wiki.

So, if your empire is xenophobic, and these pops are fanatically xenophobic, then your empire is less xenophobic. Therefore, if you want them to become less xenophobic, you want to push their ethics toward yours. This would require a negative drift.

If you can't get negative, then at least less positive might work. It's not clear to me if the divergence applies equally to each pop, or if it might just be an average of a bell curve.

If you can get some of the pops down to xenophobic, then at some point they might end up less xenophobic than your empire. At this point, you would need a positive drift to continue to reduce their xenophobic tendencies and push them towards xenophilia.

Answer 2

It is extremely difficult for a Xenophobic empire to get much use out of Xeno pops; you almost want to have high ethics divergence because if you capture an alien pop and make them be Xenophobic, the happiness penalty will be crushing.

Fortunately, you do have recourse - slavery. Slavery gives bonuses to food and mineral production, and wipes out the negative penalty for happiness. The drawback, of course, is that slaves get huge penalties to energy and research production. Typically you would have to have planets dedicated to energy and research with your own species, and have planets dedicated to minerals with the other species.

Once you have the ability to modify alien preferred environments, you can enslave some alien species to do the food / mineral stuff on your own worlds, but note that modifying your core species will count against you for Xenophobia... Xenophobes need terraforming tech, and to use the cleansing war goal to be able to terraform.

Answer 3

There is another way to change the ethics of conquered planets - when declaring war instead for "capture" try aiming for "liberate". When you'll win the war a new empire will be created on the "liberated" planets that will have the exact ethos as yours. Whats even more important, they will love you and will be more than happy to became your vassal. And after few years you can integrate them without much resistance into your empire, without creating rebellious factions.

The are two drawback of this method:

1. It costs much more (about 20-30% more in the term of war goals) to liberate rather than conquer, so you can't capture as many planets in a single war.

2. You have to wait 5 (?) years before you can integrate your subject and it will take another few years to do so (draining 5 influence per month).

   So it is a slower way, but might be worthwhile, because instead of rebellious population you'll have a nice, happy vassal ready to be your meatshield in case of war, that you can additionally harass for a tribute.