Ways to Mitigate Purge Penalties?

[Time for a Nap]

So, Commonwealth of Man is the only Xenophobe default empire in the base game. It makes sense from a roleplay standpoint that you purge the Xeno Scum from the galaxy. But there are a lot of downsides to that. Captured planets with large original populations will go from 30+ to 5 people, leaving lots of jobs unfilled and unused districts that cost you overhead.

Every time I play CoM, I always have to deal with the above, and probably other penalties I'm not even aware of. What are the most effective ways to purge? I used to try setting every species to Undesirable, thinking I need to get rid of them and their stability and happiness penalties as quickly as possible. Now I go one at a time, purging the smallest populations first.

Is there a more effective way to do this? Should I be using Displacement instead of Undesirables? What are the pros and cons of each? The internet is only able to tell me how to purge but not how to purge effectively. Thanks in advance.

[Elitewrecker PT]

The biggest difference between the purge types is speed and opinion penalty with other Empires. Displacement are still undesirables, it just takes longer and has a smaller penalty with other Empires.

[Exothermically Eclectic]

The most effective way is to not purge, because pops are power. But if you must purge, then purge fast; the longer you leave them, the bigger the problems will be.
Purging 10 pops from one planet takes quite a while. Purging 1 pop each from 10 planets is much faster. Divide and conquer applies to more than just conquest.
Displacing pops does exactly that, displaces them; that means they're going somewhere else, and that somewhere else is another empire that will be competing with you. Since pops are power, that means that unless you can totally overwhelm their infrastructure with sheer volume of displaced pops (not likely unless you're playing in a small galaxy or massively outclass most other empires to the point where you can rapidly roll over a bunch of them, in which case it doesn't matter anyway) you're weakening your own economy and strengthening your competitors, so if you absolutely must take that shortcut then be prepared for the consequences.

[Time for a Nap]

Hmmm. So in order to counter the non-diplomatic effects of purging (i.e. losing that population), I have to maximize my own population growth. I know a few ways to do that. Some early techs, the Habitability tradition, and the gene clinic building line. Thanks for the tips.

[Ryika]

引用自 Amicably Atrocious：

But if you must purge, then purge fast; the longer you leave them, the bigger the problems will be.
Purging 10 pops from one planet takes quite a while. Purging 1 pop each from 10 planets is much faster. Divide and conquer applies to more than just conquest.

This is literally the opposite of what you should do. You want your Undesirables to be stacked up and on Forced Labor, because the game only ever purges 1 pop at a time, so all the other pops will continue producing purge resources until it's their turn.

The more spread out they are, the less overall resources they will produce for you.

[mss73055]

If you don't like the climate on a planet stop Land Appropriation before invading.
Saves you 200 influence to abandon the planet and makes terraforming easier.